Dynomite

ZR-1 (90' and 91') Wilwood Rotors and C4 to C5-Z06 Front Brake Conversion with A-Molds

Specific Brake Parts by Wilwood

The KEY Element is the offset of the Rotor to match the offset of the Caliper Bracket.
This Wilwood Rotor with Z06 Caliper Modification described herein is IDENTICAL on BOTH the 90' ZR-1 and 91' ZR-1.

1. Rotors.
Wilwood SRP Drilled Performance rotors 12.8 inch diameter and 1.25 inch width with 12x7.06 Rotor Bolt Circle (160-7744-BK RH and 160-7745-LH).



2. Hats.
Two Wilwood Big Brake short offset (offset 1/4 inch) Hats (Aluminum Alloy) with 5x4.75 Wheel Stud Circle and 12x7.06 Rotor Bolt Circle (#170-7746) will fit the Wilwood SRP Drilled Performance Rotors.



3. Brake Pads.
Four (4) 15Q-8012K PolymatrixQ pads for a C5-Z06 (Wilwood is souce).

4. C5-Z06 Calipers and Brackets.


C5-Z06 Calipers Ebay
C5-Z06 Caliper Brackets Ebay

5. Bracket Bolt Kits.
#14121 (Caliper Guide Pin) and Brake Hardware Kit (Spacers and Seals) #H5634Q at O'Reilly Auto Parts.

6. Adapters.
(Corvette C4 to C5-Z06 conversion brackets, late spindle) C4 to C5-Z06 Conversion Adapters (Ebay)
(Note the countersunk surface for Bracket Boss)



7. SS Brake Lines.
C5 SS Brake Lines (Ebay)



8. Adapter Washer Spacer.
One Washers (about 1/16 inch thickness are used on each of two adapter bolts) between the Adapter and
Wheel Assembly. This setup centered the calipers on the rotors having 1/4 inch offset.

You can see the washer (one washer on each bolt) spacer between the adapter and wheel assembly. Used Red Loctite 262 on all adapter bolts.




9. Wheel Weights and Sensor Cable Bracket.
a. I had to move wheel weights as there is only 1/8 inch clearance between inside of wheel hub and C5-Z06 calipers.
b. The wheel sensor cable bracket was twisted just a bit. This assures clearance between the wheel sensor cable and the SS brake line at maximum steering angles.

Wheel weights that were between spokes moved .......Weel weights in line with a spoke moved inside spoke
inside two adjacent spokes


10. 91' Brake Upgrade to C5-Z06 with Wilwood Rotors.




11. 90' Brake Upgrade to C5-Z06 with Wilwood Rotors.




12. Performance of the Wilwood SRP Drilled Performance Rotors with Hats.
I have this same Wilwood SRP Drilled Performance Rotor brake set up on my 91' and I can tell you there is no fade.

Also the Bearing Hub does not see near as much heat on a high speed stop.

The trick with the Wilwoods is the Hat. As you can see there is limited transfer of heat possible from the Rotor to the Hat. That keeps the Hub cooler than a solid mass Rotor/Hub. So the front end Hub Bearings do not see near as much heat when I stop in my relatively short 1/4 mile runouts from 120 mph



13. Wheel Dimensions that will fit on this brake Set-Up.

This would be the limit of a wheel inner dimensions which would fit/clear the C5-Z06 Brake Caliper Set-UP.
Rather than try to measure the offset and the maximum radius of the Caliper it was easier just to measure the A-Mold wheel which just clears the spokes as well as the C5-Z06 Caliper outer radius as shown below. I would say this is Minimum Clearance. The clearances of this Set-Up is on the order of 1/4 inch on spoke and 1/8 inch on wheel inner radius so very close. There is slop in the Caliper pins riding in the bracket so this clearance is definitely required.



A. Spoke Offset.
The Spoke Offset from hub surface is 1 inch at the widest part (outer edge) of the Caliper.
The wheel weights are located on the inner rim and single stacked.



B. Wheel inner diameter.

Two Inner wheel diameters are shown. The one on the left is the wheel diameter at the hub surface which is 15.25 inches (this would coincide with the the radius of the outer part of the caliper) . The Second wheel diameter on right is the wheel diameter at 4.5 inches up from the spoke where the inner (larger radius) part of the caliper which is larger radius sits which dimension is 15.75 inches.



14. Will this brake Set-Up work with Stock Sawblades.

I measured a stock Sawblade wheel and found the inside diameter of Saw Blade Rims is about identical to A-Mold Rims at the two critical locations of the Calipers. I also measured the spoke Offset from the Hub and found it to be .75 inch as compared to 1 inch for A-Molds. When installing the Sawbade wheel the spoke of the Sawblade JUST came into contact with the C5 Z06 Caliper as shown. In other words I would say the offset of the stock Sawblade wheel is 1/4 inch short of what would be required (3/4 inch vrs 1 inch).



It would be easy to place a 1/4 inch spacer on the Hat of the Wilwood Rotor but you would then be 1/4 inch shorter on the stud length for the wheel nuts which you end up with 1/4 inch less than the bit over 1/2 inch threaded contact now (as I view my Hubs with the Wilwood Rotors installed with Hats).

Last UPDATE of post 41 Dec, 2017

Dynomite

Going from 3:45 to 4:10 Differential

I need Ratech 'Deluxe' Install kit-3012K from http://ratech.stores.yahoo.net/coax84d44.html

Mopar P5007043 viper gears, from http://www.trademotion.com/auction/i...50&catalogid=0 Call Jeromy for prices, under $300 shipped.

Spicer # 707018X from http://www.drivetrainspecialists.com...oduct-446.html

Marc Haibeck 13/43 speedometer gears from http://www.zr1specialist.com/HAT%20W...on%20Gears.htm

I convert the carrier caps from 1/2" bolts over to 1/2' ARP studs. ARP Part Numbers:
4 x Stud - AR4.060-LB
4 x Hex Nut - 200-8607
4 x Washer - 200-8514
To order I call ARP Order Desk & Technical Support: 800.826.3045
Use a 1/2"-13 bottoming tap to deepen the threads.

As long as I am there under the differential, Get a Denny's Driveshafts 1350 kit for C4 aluminum half shafts from http://www.dennysdriveshaft.com/p422...build_kit.html

Install the differential drain plug from Corvette Central
http://www.parts123.com/parts123/yb....Z5Z5Z50000050F

To permanently stop rust I use POR-15 Stirling Silver and Gloss Black paint
http://www.por15.com/POR-15-Rust-Pre...nt/products/1/


Last UPDATE of post 42 Aug, 2012

Dynomite

LT5 Final Inspection including Brake Tricks

1. Firing Order Check
a. 18436572
b. Drivers side bank from front of engine is 1357
c. Passenger side bank from front of engine is 2468

2. Oil Pressure check at 55 lbs...........................3. Fuel Pressure Test at 45 psi.


4. Compression Check
a. 220-230 lbs on all cylinders with throttle closed.


5. Leak Down Testers
a. Low pressure (15 psi) Leak Down tester....... b. High pressure (100 psi) Leak Down Tester (Longacre Racing Products).


6. Wilwood Rotors with C5 ZO6 Calipers
a. Wilwood rotors with C5 Z06 Calipers will stop a freight train.
b. Had to move wheel weights from Caliper area for clearance.



It is running perfectly idling at a smooth 850
All coolant hoses are hot so coolant refill trick is proven to work. NO issues after I finally got my SAMCO hoses to stay on...LOL.

7. Battery disconnect trick (rough cold idle)
Marc Haibeck descibed this unique situation regarding an initial rough cold idle. Fuel Trims are fueling data that are displayed on an engine data scanner. I have been disconnecting the battery several times during the day after each ride to correct a vibration issue I had behind the speedometer in the dash. The vibration was actually my top lose which telescoped down to the dash. I also did some wiring mods around the battery and installed a rebuilt BOSE system which I disconnected the battery several times.

Each time I disconnected the battery, I lost the system's learned fuel corrections (Fuel Trim). The system self tunes the low load fueling after it is warmed up. It then uses the learned values on the next cold start until it is warm enough to go into closed loop and resumes learning. Exactly what I was experiencing as it goes into closed loop around 167 deg engine temperature. Then ran smooth having to relearn low load fueling.

It has some heavy duty acceleration and it is smooth at any and all rpm. No hesitation at all. Unbelievably smooth and very very fast.......WOW!!!!


Last UPDATE of post 43 Dec, 2017

Dynomite

Accessories

1. Cobra XRS-9955 15 Band 360° Police Cop Radar Laser Detector w/DataGrafix Display.

But the mount that comes with Cobra is too small so get this mount.
Power Grip Suction Mount For the COBRA Radar Detector 9-15 Band & Recent Models



The Cobra's seem to catch everything including garage door openers
Still trying to get a range for a hand held radar gun....will confirm when I catch one.

And sometimes I get a message Rail Crossing and I should be looking for Trains
But you can tune most unnecessary things out with settings.

Just last night found five police/patrol cars I did not know were around until Cobra blasted me (I turned down Cobra Volume).

The Cobra will also tell you battery voltage (digital) on the fly.

The reviews of the Cobra XRS-9955 on line seem pretty good.
I have four Cobras including my wife's who needs a radar detector much more than myself just because she is not normally looking for "cops"

2. Suction Window Mount and C340 Garmin.

The mount which was ordered separately (Super Grip Suction Mount For the COBRA Radar Detector) is the same mount I use for my Garmin StreetPilot c340s. The C340s are a bit older technology but hot damn...they are good and very easy to use. I always have a C340 in the C4 Corvette.

3. USB Adapter.

And....last but not least........I use this USB adapter for the Corvette Cigarettes Lighter which is dual port and allows the cover to be closed.



Last UPDATE of post 44 Dec, 2017

Dynomite

Exhaust System Replace with Headers

On a 91' the CATS are welded to the exhaust manifolds and the mufflers are welded to the exhaust pipes. There is only one joint that is bolted with a flange between the CATS and the "pipes" on each side (you can see the flanges in the picture). The exhaust hangers are all bolted (two on the twin pipes and one each on the exhaust mufflers).

I am sure a 90' exhaust unbolts just like my 91' . Also got rid of the Air Induction System.



You need two new exhaust manifold gaskets and maybe a dipstick tube seal.
Exhaust Manifold Gasket
Dipstick Tube Seal

And Maybe Stage 8 Header Bolts.
LT5 Summit Racing 8905 LT5 8mm x 1.25 The underhead length is 25 mm or about .98 inches

1. Remove REAR innner wheel panels (Drivers side and Passenger side) first.
...a. Two Torx T15 to rear louvered side panel.
...b. Three Torx T27 to rear louvered side panel.
...c. Four 10mm bolts in vertical line attached to center panel.
...d. One 10 mm bolt under rear wheel panel attached to frame.
...e. Two 10 mm bolts lower rear attached to rear frame.
...f. Two 7 mm bolts along top edge drivers side of rear wheel panel attaching secondary injector module.
2. Remove 10 mm bolt that holds dipstick tube to manifold.
3. Remove Dipstick Tube. (plug dip stick tube hole temporarily)
4. Loosen exhaust connecting flanges just to the rear of the CATS (three bolts each) Use some WD40 to start with on all bolts.
5. Leave the CATS connected to the Exhaust Manifolds.
6. Remove Two Hanger bolts (Trans and Differential). Leave hangers in place.
7. Remove rear "L" Hanger on Stock Mufflers and drop mufflers a few inches supporting mufflers on blocks.
8. Finish removing 3 bolts from connecting flanges (step #4 above) and drop exhaust system to floor (drag out to rear).
9. Remove exhaust manifold tin heat isolation covers.
10. Remove Air Induction main tubes and rest of Air Induction system including pump.
...a. Associated with the Air Injection system is one vacuum line on the drivers side fender skirt above the shock tower.
...b. I eliminated the "T" and just moved the "Y" in front of "T" about 3 inches and plugged the "Y" back in where the "T" was.
11. Remove (I think 13 mm) nut on stud (stud may come out) in center lower of each Exhaust Manifold (90's - 92's only).
12. Remove exhaust manifold bolts (10mm) using various 3/8 inch socket extensions, universals, and flex head ratchet wrench.
Do NOT slip wrenches on the 10mm hex head of the exhaust manifold bolts when you try to first loosen them jimming the hex in any way!!!
13. Drop Stock Exhaust Manifolds with CATS to floor and slide out to side.
...a. Leave the CATS connected to the manifolds.
14. Remove old Exhaust Manifold Gaskets and clean exhaust surfaces on block.



I use the wobble extensions on almost everything. The wobble extensions are in first picture and flex ratchet combination wrenches in second picture.


You will notice what allows the wobble. A 3/8 inch universal in the second picture.



There are all sorts of socket combinations you can get but these four tools/tool sets will get er done assuming you have a good 3/8 inch and 1/4 inch socket wrench and set of metric sockets. The BIG problem in removing the exhaust manifold is getting wrenches in such a small space. I actually use 1/4 inch socket, 1/4 inch socket extensions, 1/4 inch socket wrench, and 1/4 inch universal as the 1/4 inch are much easier to work in tight areas. When you get to installing Headers....I sometimes use two universals and two extensions with one 1/4 inch ratchet wrench with Stage 8 Header bolts (it actually works).

Post 87 - Installing Headers and Exhaust

Now if you drop stuff....here is the tool.

A 16 inch straight Hemostat (Ebay has many). On the Ebay Search....just type in Hemostat and the length you would like and also type in Curved or Straight (Hemostat 16 straight for this one). The beauty in addition to being sleek to reach tight spaces is that it can be locked (ratched locked) once you get hold of what you dropped.


Particularily useful for Stainless steel and Aluminum Nuts, Bolts and Washers.

Last UPDATE of post 45 Dec, 2017

Dynomite

Exhaust Headers Locking Bolt Tricks

Use a bit of antiseize on Header Bolts with the Stage 8 Locks. Also use a bit of antiseize on all spark plugs.

Here are Locking Header Bolt Kits (LT5 and L98)

LT5 Summit Racing M-9432-A54
LT5 8mm x 1.25 The underhead length is 22 mm or about .87 inches


LT5 Summit Racing 8905
LT5 8mm x 1.25 The underhead length is 25 mm or about .98 inches

L98 Summit Racing 8911A
L98 3/8 x 16 the underhead length is 1.00 inches



Only works with Headers however as the individual locks use the header pipes as a stop. You do not need a Header Bolt in EVERY threaded hole. On my installation of SW Headers, removed the motor mount insulation each side as the insulation on top of mount was touching the headers.



Last UPDATE of post 46 Dec, 2017

Dynomite

Installing the LT5 with Headers and the O2 Sensors Functionality

1. The first two items to be removed before the engine can be lifted (with Headers Installed) are the Wiper Motor and AC Temperature Sensor (Passenger Side Fire Wall). The last items to be installed will be the Wiper Motor and AC Temperature Sensor. The LT5 was lifted with Headers, Injector Housing, Alternator, Pressure Plate, Belt Tensioner, and lower engine Radiator Hose installed. See How to Replace the Wiper Motor

A/C Temp Sensor........................Wiper Motor.........Do NOT use standard Lift Eyes installing LT5 with Headers


The Hood was NOT REMOVED for this installation of the LT5 with Fuel Rails, Plenum, and Bell Housing installed on the LT5 after the LT5 installation in the ZR1.

2. LT5 Lifting Attachments.

Make sure the LT5 sits level from side to side and a Leveler Bar is used to tip the engine to the rear. Do not use the standard Lift eyes (Passenger side rear and Drivers side front) because as you tilt the engine to the rear the load leveler will shift to the Drivers side rotating the engine lower on the passenger side. I use nylon straps around Harmonic Balancer (front) and Pressure Plate (rear). The LT5 then does not rotate from side to side with each Header remaining at the same height. The LT5 can be tilted to the rear with the Load Leveler.

See Lifting the LT5



3. The Installation and verification of O2 Sensors Functionality.

A. O2 Sensor Wiring and Codes.
1. The O2 sensor uses two wires for a heating circuit.
2. The third wire is for voltage generated by the O2 sensor transmitted to the ECM.
3. Codes:
Code 44 Oxygen Sensor (Left Bank Lean)
Code 45 Oxygen Sensor (Left Bank Rich)
Code 63 Right Oxygen Sensor Circuit Open
Code 64 Right Oxygen Sensor (Right Bank Lean)
Code 65 Right Oxygen Sensor (Right Bank Rich)

B. O2 Sensor Functional Requirements.
The O2 sensor readings are not used at first until the O2 sensor becomes heated and functional which it will then generate a voltage of which .45 volts is average for optimum oxygen. The two heating wires will show a resistance of .40 ohms more or less when functional.

C. Verifying the Oxygen Reading Functionality of the O2 Sensor.
1. The O2 sensor can be checked by removing it from the vehicle.
2. Connect a digital voltmeter to the sensor;
3. Use a propane torch to heat the sensor element.
4. With a zirconia O2 sensor, connect the positive test lead to the O2 sensors lead wire, and the negative test lead to the sensor housing or shell (ground).
5. Hold the sensor with pliers, then use the propane torch to heat the sensing element.
The flame consumes most of the oxygen, so the sensor should generate a “rich” voltage signal of about 0.9 volts within 60 seconds or less.
6. Next, remove the flame while observing the voltmeter. The sensor reading should drop to less than 0.1 volt within three seconds if the sensor is good.

D. Verifying the Functionality of the O2 Sensor Heating Circuit.
1. To test the sensor’s heater circuit, connect an ohmeter (set on low scale) across the sensor’s two
heater wires.
2. If the heater circuit is okay, the meter will register a resistance reading. The actual reading is not important so long as the meter registers
something other than an open circuit.
3. Marc Haibeck suggests An easy way to test the heating Circuit of the O2 Sensor is to turn the ignition on with the engine off and the engine cold. After two minutes you will be able to feel the sensors warming up with your hand.

E. Verifying the Continuity of the O2 Sensor Connections to the ECM.
1. Marc Haibeck suggests The O2 Sensor voltage can be measured at the ECM pin A16 for the right side and Pin C15 for the left side.
2. One can Test the Voltage Output of the O2 Sensors on a warmed up and Running Engine (after the O2 Sensor has warmed up from its Own O2 Sensor Heater or by Running the Engine for a short time).
3. Stick a needle in Pin A16 or Pin C15 at the ECM with a Volt Meter attached and read .45 volts for a normal running engine or up to .9 Volts for an Engine Running Rich Situation and less than .45 Volts for an Engine Running Lean Situation.

NOTES:
Originally Posted by XfireZ51
Originally, O2 sensors were single wire with no heating circuit. Heating was included strictly as a means of "lighting" the O2 sensor quicker rather than wait for the Hot Exhaust to heat the O2 Sensor up to operating temperatures (Get into Closed Loop operation sooner). Most of the emissions happens in start up and warm up. The sensor ground is internal to the ECM. The ECM reads the signal coming through the Pins A16 and Pins C15 wire at the ECM which is white wire or terminal C at the sensor. More than .45v and its an engine rich situation and less than .45v an engine lean situation. The 2 black wires at the sensor (terminal A&B) are strictly for the heating element (power and ground).

The variation in voltage comes from the outside air versus the air within the sensor. That is why it is important NOT to cover up the wires as they go into the O2 sensor. Essentially, the outside air is reference.

Last UPDATE of post 47 Dec, 2017

Dynomite

1990 and 1991 Fuses/Additional 12V Connector

1. 1990 Primary and Auxiliary Fuse Panel.
The Primary Fuse Panel is located on the passenger side to the right of the glove box and can be accessed by opening the passenger side door. The Auxiliary Fuse Panels are located under the passenger side dash. Remove the hush panel two screws (7mm heads near front of black plastic hush panel and one 7mm head screw located inside the passenger side Primary Fuse Panel Cover). The Primary Fuse Panel Cover frame has three screws (either Torx (91') or 7mm hex head (90')).



3. Changes to the Fuse Panels in 1991.
In 1991 some changes were made to the Primary Fuse Panel and a second Auxiliary Fuse Panel was added.
1. The L INST was added to the 1991 Auxilary Fuse Panel. The INST on the 1990 Primary Fuse Panel was relabled to R INST on the 1991 Primary Fuse Panel.
2. The CRUISE amps was increased from 3 amps (1990 Primary Fuse Panel) to 10 amps on the 1991 Primary Fuse Panel.
3. The A/C amps was decreased from 25 amps (1990 Primary Fuse Panel) to 10 amps on the 1991 Primary Fuse Panel.

On the 1991 Aux 2 Fuse Panel (The 1991 Auxiliary Fuse Panel is located under the passenger hush panel).
10 AMP is radio, B CONV is lighter and B+ for the accessory harness in console, I CONV is switch wire in console.

10 AMP top is L INST......left door courtesy, LH window switch, Heater and AC control, DIC. Power mirror and radio control lamps. There's a R INST 10 AMP in the main block.

1991 Primary and Auxiliary Fuse Panels.



4. Marc Haibeck and Electrical Issues.

Marc Haibeck Checking Injector Resistance With Plenum In Place
Marc Haibeck Checking Secondary Operation Plenum In Place
Marc Haibeck and the ALDL Connector

5. 12V Swivel Lighter Plug with 2 Outlets and USB Port

The RoadPro RPP2SWVUSB 12V Swivel Lighter Plug with 2 Outlets and USB Port provides additional 12v power (Cobra and Garmin for example) as well as USB power for charging cell phones.



The RoadPro easily fits into the existing and only 12v Auxiliary receptacle and is on a swivel so can be tilted as required. Also the RoadPro has a green light when powered. I use the coiled charging cords on everything for a cleaner installation.



Last UPDATE of post 48 Dec, 2017

Dynomite

Backup Tail Light Switch and Alternators

1. Backup Tail Light Switch.

Sources.....
Backup Tail Light Switch



I think the backup tail light switch is that connector on the top left
You would have to remove the Clutch Slave Cylinder to get to that switch for sure.

The switch is 22mm and I could get a 22mm box wrench on it even though the switch is recessed a bit (I am not sure if you can sneak a box wrench up there with transmission installed). The electrical plug to the switch has one tab you have to disengage to remove the electrical plug.



2. Alternators.

The Ultima 124 Amp Alternator - Remanufactured R111799A from O'Reillys fits the 1990 ZR-1 perfectly. This Alternator costs $100. The Ultima is a bit heavier with the body a bit larger in diameter with identical mounting points as the stock Alternator. The Ultima 124 Amp Alternator fits perfectly under the Plenum of the LT5.

I have taken this #72 ZR-1 with Phil's Improved Fuel Pressure Regulator and the Rebuilt Ultima 124 Amp Alternator on several Quarter Mile Runs and one 100 mile round trip with NO ISSUES. I have yet had to replace any Rebuilt Alternators from O'Reillys



3. Installing All Aluminum Alternator Pulley.

Both the bottom and top Alternator Mountings and the threaded hole at rear of Alternator that excepts the bolt from the small angled brace that attaches to the Injector Housing Bolt are ALL identical to the stock Alternator. The Hot wire can be seen just above the rear mounting bolt and is actually better positioned on this Ultima 124 amp alternator than the stock alternator.

See All Aluminum Alternator Pulley



4. Minor Modification of Air Horn.

The smaller single vacuum port (nipple) on the Air Horn pointing back under TB on 90' (90' only) is for vapor Canister Control and which vacuum line is connected to the Charcoal Vapor Canister control valve under the Drivers Side Headlight (on the 90'). This single Vapor Canister Control vacuum nipple almost touches the Ultima 124 Amp Alternator body and has to be bent just a bit as shown in the second photo. This assures the Alternator is not touching the rubber vacuum connector that fits on the vacuum nipple of the Air Horn.




Last UPDATE of post 49 Aug, 2020

Dynomite

Replacing the Windshield and Wiper Motor (ZR-1 #72)

A. Windshield.
I bought a New Windshield and weather stripping for a 1990 ZR-1 (#72) and had the Windshield replaced by Safelite (I specifically said I did not need a warranty since I was furnishing the molding as well as the windshield).

Windshield BEFORE Replacement showing severe Delamination.


Safelite Just installed a Windshield and Weather stripping in a 1990 ZR-1 for $150. I furnished the Windshield and Weather Stripping

This is number 72 one of the first 1990s built.
I also have the last 1990 ZR-1 sold to public (#3032) and it has no windshield issues.

This is BEFORE and AFTER photos

Safelite did a Perfect Job

I got the Windshield and Weather Stripping from David Johnson and have to say the Windshield is perfect in every way as is the Weather Stripping. Safelite was pleasantly surprised how good this Windshield Installation ended ....and they have done other Windshield Installations on Corvettes with Windshields and Weather Stripping they have provided themselves (This was the best they had seen).




B. Wiper Motor.
I remove the wiper motor when removing and installing the LT5 engine.
Have a Magnetic Pick Up Tool handy as you may drop nuts or the Wiper Motor Arm as you remove the Wiper Motor.

REMOVAL of Wiper Motor
1. Reach through Windshield Wiper Grille (the small removable access cover above windshield wiper motor arm connection should pop off using a flat screw driiver). See Left Photo below.
2. With socket wrench just loosen the two 10 mm nuts on each (left and right) windshield wiper arm (DO NOT REMOVE THOSE NUTS).
3. Slide both windshield wiper arms off the Wiper Motor Arm sockets Relube those windshield wiper Arm sockets when reinstalling the windshield wiper arms.
4. Remove the 13 mm nut holding the Wiper Motor Arm to the Wiper Motor and remove the Wiper Motor Arm (The Wiper Arm should be pointing toward the Drivers Side).
5. Remove the three Wiper Motor bolts (10 mm socket using 1/4 inch socket wrench) holding the Windshield Wiper Motor in place on the Fire Wall and Lift the Wiper Motor.
6. With the Wiper Motor lifted, disconnect three electrical connections to the Wiper Motor and Remove Wiper Motor.

INSTALLATION of Wiper Motor
1. Connect the Lower Electrical Connector to the Wiper Motor and position the Wiper Motor on the Fire Wall.
2. Install the three Wiper Motor Bolts (10 mm Socket using 1/4 inch socket wrench).
3. Locate the Wiper Motor Arm pointing horizontally toward the drivers side and install the 13 mm nut on the Wiper Motor Drive Shaft (the Wiper Motor Drive shaft is keyed to match a slot in the Wiper Motor Arm).
4.To reinstall the wiper arms reaching through the removable access with a long needle nose pliers and slip the arms back onto the Wiper Arm sockets.
5. Position each wiper blade at the bottom (stored position) and tighten each pair of 10 mm nuts on each Wiper Arm. (this is an adjustment if after testing the Wipers you find they Swing too far off the windshield or do not return to their proper resting position).
6. Connect the two remaining Wiper Motor Electrical Connectors.
7. Test the Windshield Wipers for total Swing (a wet windshield will make a difference) and adjust as cited in step #5 above.
8. Snap the small Windshield Wiper Grille back in place.

Front and Back of Windshield Wiper Motor, Wiper Motor Arm, 13 mm Wiper Motor Shaft nut


Windshield Wiper Grille........................................ .....Magnetic Pick Up Tool just in case you drop anything


Notes:
1. You want to remove the wiper motor if you are removing the engine to gain adequate clearance between the drivers side Cam Cover and Firewall.

Last UPDATE of post 50 Dec, 2017

Dynomite

1. CMHSL LED install on my ZR-1

Ecklers has the chrome billet louvers and they are not cheap...but then again...they are billet 3D and very very nice.



Ecklers has the LED tail light kit (48 LED per light)
I assume you have the 48 LED per tail light?

CorvetteHID has both the LED tail light kit (30 LED per light) as well as the CHMSL LED (3 LED per bulb). CorvetteHID will send a (6 LED per bulb) CHMSL kit as long as supplies last even if you buy the 3 LED bulb CHMSL kit shown on their web site. CorvetteHID suggests 30 LED tail lights are as bright as 48 LED tail lights which I am not sure.



2. Full Power Key Reconditon

Great work Kevin

Kevin......I have used your write up to rebuild three 1990 Power Keys so far and they ALL function perfectly.....You DA MAN

Especially the use of Channel Locks to remove the locking ring :thumbsup:

Using needle nose pliers I bent the "blades" shown in red to their new position shown in yellow (the bending taking place at point A and point B). This allows the cam of the switch to fully contact the yellow "blades" while fully closing the silver contacts located in the top right corner of the photo of the Full Power Switch.

The original position of the "blades" shown in red actually did not stay in contact with the cam requiring jiggling the switch back and forth until contact was made of the cam with the "blades". Then vibration would break that contact and you have a non working Power Switch or intermittent working Power Switch in which the silver contacts on the top right would not stay fully closed. You could feel that the Power Key was loose with no resistance in the Full Power Mode indicating there was no contact with the "blades".

I used a bit of white grease on the cam and cam pin.



I think this applies to a 1990 ZR-1 only.......


3. Calculating Alternator Pulley Diameter for various current loads related to engine rpm.

We first calculate diameter of belt surface on Harmonic Balancer to convert rpm to surpentine belt speed?

The Harmonic Balancer diameter is 7-1/8 inch to outer lip (90' ZR1). The surpentine belt riding surface is about 1/8 in less radius so surpentine belt riding surface diameter would be 6-7/8 inches (6.875 inches).

If the alternator puts out 150 amp max and 120 amp at idle....the question is at what rpms is alternator spinning when the engine is idling at 850 rpm with a surpentine belt speed of 18,349 inches per minute. (6.875 inches x 3.14) in per rev x 850 rpm = 18,349 inches per minute.

My alternator pully is about 68mm (2.7 inches) diameter (I just bought two new alternator pulleys recently).



At a Surpentine Belt speed (idle) of 18,349 inches per minute, that alternator would be spinning at (18,349 inches per minute)/(2.7 inches x3.14) = 2,164 rpm (alternator spin rate) at idle (engine idle speed 850 rpm).

Or...just divide the Harmonic Balancer Diameter by the Alternator Pulley Diameter and multiply by engine idle speed to get Alternator Idle speed.

So the question might be at what Alternator idle speed the alternator still puts out the current needed to keep up with ZR1 current usage at idle (assuming you are not sitting there with head lights on at idle). Size that alternator pulley accoringly and then see what the maximum alternator rpm might be at 7,000 rpm engine speed (making sure you are not overspinning the alternator). If you are overspinning the alternator and do that often, get a larger alternator pulley and suffer the consequences when sitting at a stop light with lights on loosing battery charge as your alternator cannot keep up with current load.

After figuring out the alternator pulley size required, get a surpentine belt length accordingly.

4. Perfect Size identical to Stock Billet Aluminum Alternator Pulley.

See Also a Perfect Size identical to Stock Billet Aluminum Alternator Pulley All Aluminum Alternator Pulley



Last UPDATE of post 51 Aug, 2019

Dynomite

Starter, Starter Relay, Wiring Harness, Battery, and Plugs Tricks

1. Starter Contacts.

I had a NO START condition on a 90' and after I towed it for a start....got home and it fired right up. I would have liked to hot wire the starter (purple wire) when that happens to see if it is the starter or starter ground circuit. Or check that purple wire for 12 volts when I turn the switch to start. I lean toward ground circuit or sticky starter solenoid. Another indication would be if when you turn the ignition key to start do the lights dim for example indicating a current draw to the starter solenoid/starter.

If the solenoid does not move (no clicking indicating the Starter Solenoid moved) as in my case then a sticky Solenoid or Solenoid Ground Connection. If the Solenoid clicked/moved...then bad Solenoid contacts or bad connection Battery cable (Positive) to starter/battery or bad ground (Negative) engine to battery. The moving Solenoid contacts can be easily wire brushed and the fixed contacts can be easily shined up with emery cloth.

The Starter Solenoid is shown in the left photo with slight burnt contacts in right photo.


The Solenoid contacts in left photo were wire brushed clean in right photo.
Also use a bit of emery cloth on the two fixed contacts.


Photo provided by mgbrv8 Complete starter rebuild by mgbrv8 (Dave)

Check the two bearings on each end of the Armature for roughness by spinning with your fingers. If any roughness, replace with new bearings (pulling the bearings with a small bearing puller).



2. Starter Relay Tricks.

See Item #2 Electrical Ground Connections and Installing Starter Relay

60 / 80 AMP RELAY SPDT SINGLE POLE DOUBLE THROW NEW 654
Installed under ECM and in slot between brake booster and fire wall (perfect place for location of Relay).

Wiring modified a bit to assure Pin #87a is not hot at any time.
Pin #30: Purple wire to starter (use 3/8 inch connector on relay).
Pin #87: Red wire battery positive 12v use 3/8 inch connector on relay
(Same gauge wire as purple wire connected to battery positive multiple connection post).
Pin #86: Battery ground (1/4 inch connector on relay connected to ground where battery 12 gauge wire grounded).
Pin #85: Purple wire from clutch switch in wire bundle under ECM use 1/4 inch connector on relay (Red wire on early 1990 ZR-1).
Pin #87a: Not hot at any time and not used.


Insert a short 1/2 inch long section of plastic hose
over the center connector on the Relay which is NOT
used in this application.


3. Primary Front Wire Harness Relocated Tricks.
The Drivers side wire harness to the front (lights, fans, etc.) has been relocated UNDER the Drivers Side A Arm cleaning up that area near the Oil Catch Can.
a. Jack Drivers side such that front wheel is off ground (free spinning) and remove disconnect upper "A" Arm.
b. Slide large wire harness below "A" Arm sitting directly on frame rail and reconnect "A" Arm.
c. I disconnected wire going to front wheel from small frame bracket and used that bracket to attach the larger wire harness under the "A" Arm.

Passenger Side HVAC Wire Harness...............................Drivers Side Wire Harnes to Radiator Fans


4. Battery Disconnect for Storage.

I am the only one that disconnects the battery negative cable
Just like ALL the batteries on the Walmart shelf

I used to use battery tenders (many of them) on tractors, ATVs, trucks, cars and had electrical extension cords running all over in the shed. I figured there was more chance of fire than damage from a sulfated/dead battery.

I finally got rid of all electrical extension cords and just disconnected the battery negative terminals. I have found that over winter storage (including the Z) and even compared to a week of leaving the battery connected there is a BIG difference in battery condition (with disconnected negative battery cable) with all batteries now fully charged condition all the time with the Disconnect Switch (I make sure the battery is FULLY CHARGED before disconnecting the battery negative cable)

From experience I get normal battery life using the battery negative cable disconnect method with no issues (not even an issue of wearing out the battery side connect stud on the Z)

Even after several months of battery disconnect I can reconnect the battery and the Z (as well as all other tractors, ATV, trucks, cars) start normally. And....I have NO battery cable connection corrosion and have possibly reduced corrosion of ALL ground connections on frame and engine block.

The Battery Disconnect Switch TIPS



5. Spark Plugs Tricks.

For my 91' NGK Iridium BKR5EIX Eagle
Gapped .043".

I will use anti-sieze on stainless steel bolts, spark plugs, and header bolts (Permatex Anti-Sieze 133A).




Last UPDATE of post 52 Dec, 2017

Dynomite

Electrical Grounds and Installing Starter Relay

1. Electrical Ground Connections.
There are two engine block ground connections (multiple grounds each) located just above the Bell Housing (rear of engine block) one on each side of the engine. There are several ground connections on the chassis near the battery frame rail and other ground connections near chassis components. There is also an engine to chassis ground strap from drivers side of engine block (on side rear of engine block) to drivers side frame rail. The main Battery negative cable attaches to the side of the engine block just in front of the Bell Housing (primarily for the starter ground).

Check for ground continuity of any suspect component using an ohm meter. With one probe on the negative battery terminal and the other probe on the negative terminal of the suspect component you should get zero ohms with ignition key off as most components are not grounded through any switch.

Loosening those two engine block connections will not be easy as I mistakenly left the HVAC fan ground disconnected when installing the engine last time from the passenger side engine ground connection. I tried to get at the passenger side block ground connection from underneath (It could be very difficult) and I have Headers which makes the underneath approach considerably different.

I decided to connect that HVAC fan ground to the rear most Plenum bolt instead which works perfectly as it helps keep that passenger side wire harness in place.

Disconnect ground wires, clean surfaces, clean grounding bolts or screws, use star washers if applicable.

As an aside.....and I am prolly the only one on this Forum......I do NOT use trickle chargers but rather disconnect negative battery connection if ZR-1, Toyota Truck, JD Tractor sits for a period of time without starting. When I reconnect the negative battery connection (even when sitting disconnected over winter) the ZR-1, Toyota Truck, JD Tractor fires right up. I do not have power leaking through all the ground connections or trickle chargers powered up with wires strung all over. Disconnecting a trickle charger takes longer than just reconnecting the negative battery connection.

In one of the photos below there is a Green Ground Wire to Chassis.
that Green Wire is the New Starter Relay Ground Wire Starter Relay, Wiring Harness, Battery, and Plugs Tricks

Ground Connection from Bat and Engine to Chassis .............................Ground Strap Connection to Engine
(green wire is NEW starter Relay ground)



Ground Connections Bolt to Engine Pass Side....................Ground Connections Bolt to Engine Drivers Side


Torx #30 to remove Drivers side Batt Panel....................5/16 inch Flex Ratchet to remove Negative Batt Terminal
SS Allen Head Bat Hold Down bolt shown..........................I remove if ZR-1 left sitting for more than two days


2. Starter Relay Installation.

Marc Haibeck describes the electrical schematics and further identifies that "in ’93 GM improved the starter solenoid circuit wiring. The clutch switch connections were moved to the armature side of the start relay. This reduces the load on the clutch switch from 30 amps to .2 amp. It also eliminates the approximately .050 volt normal voltage drop across the clutch switch and its wiring at 30 amps". See Starting Issues by Marc Haibeck

Look at this on eBay:
60 / 80 AMP RELAY SPDT SINGLE POLE DOUBLE THROW NEW 654

I have had several types of No Starts in 1991s and 1990s and the Starter Relay in conjunction with Starter Solenoid Restoration cured them all.

Keep in mind the starter Solenoid wiring in this very early 1990 is 12 gauge red (NOT PURPLE) which is rare.

I will start here but keep in mind these posts will be deleted in a day as I do not want to Hijack this thread with a No Start Relay Detailed Installation Discussion.

Remove ECM Top Cover and two 10 mm Nuts holding ECM in place.
Remove three Torx T-30 Fender Bolts holding the side cover in place.



Remove Top 10 mm Bolt holding Side Cover in place.
Loosen (do not remove) lower 10 mm bolt in the slot provided.


The side cover will slide out as the lower bolt pad is slotted.


Remove the battery Hold Down Bolt (I modified that bolt with an 8 mm Allen Head Stainless Steel bolt).


Remove Battery Connections using 5/16 Flex Ratched Wrench. Remove two 10 mm bolts from Battery Platform.



Remove cable tie which is inserted in hole in plate securing bottom of Battery Platform.
Remove two lower 10 mm screws holding Battery Platform.


Remove second 10 mm screw using open end 10 mm wrench. Remove Battery Platform.



Use 12 gauge wire and 12 gauge 3/8 inch female and 1/4 inch female Connectors which connect to the Relay.
Use 1/4 inch Connectors for Battery and Ground Connections. All 12 gauge Connectors.


Insert a short 1/2 inch long section of plastic hose
over the center connector (87a) on the Relay which is NOT
used in this application.


The ground wire for the relay will be attached to the frame rail just behind the battery
(behind the INFL REST Sensor) in the same location as the Battery 12 gauge Ground wire.
Make two 24 inch 12 gauge wires with the 1/4 inch bolt connection on one end.
One wire will have the 3/8 inch 12 gauge female connector on the other end and
one wire will have the 1/4 inch 12 gauge female connector on the other end.

Use a couple cable ties to secure the two 24 inch 12 gauge wires away from the battery
but secured to existing cables. Paint with Black Rustoleum over the frame rail ground connection
to provide a moister barrier.


Locate the 12 gauge purple wire (red 12 gauge wire in my case of the Early 1990 ZR-1) and
cut the wire such that the end leading to the starter Solenoid sticks our far enough that
it can be connected directly to the Relay. Solder a 4 inch 12 gauge wire extension to the 12 gauge
purple wire coming from the Clutch Switch making it long enough to reach the Relay being installed.
Install a 3/8 inch 12 gauge Female Connector on the wire leading to the starter Solenoid.
Install a 1/4 inch 12 gauge Female Connector on the wire coming from the Clutch Switch Installed
on the end of the 4 inch wire added as an extension.

The Hot wire is attached to the Junction Block with a 12 gauge 1/4 inch connector
(one of the 24 inch wires made up with a 3/8 inch 12 gauge female Connector) and
secured to the top of the Junction Block as shown with a 10 mm nut).
The other 24 inch wire made up with a 1/4 inch 12 gauge Female Connector is secured
with a bolt to the same location as the battery 12 gauge ground wire (bolted to the frame rail
just behind the INFL REST Sensor).


We now have four 12 gauge wires (two with 3/8 inch 12 gauge Female Connectors and two with 1/4 inch
12 gauge Female Connectors shown.

The 12 gauge wire with 3/8 inch 12 gauge Female Connector going to Starter Solenoid
connects to post #30 of the Relay. The other 12 gauge wire with 3/8 inch 12 gauge
Female Connector connects to Post #87 of the Relay (this is always HOT when the key is on).
The 12 gauge wire with 1/4 inch 12 gauge Female Connector coming from the Clutch Switch
connects to either of the two smaller connections on the Relay. The second 12 gauge wire
with 1/4 inch 12 gauge Female Connector (one of the 24 inch wires) which is connected to ground
connects to the other of the two smaller connections on the Relay.
Make sure the clear plastic hose section is secure on the middle post (#87a) of the relay as an insulator.
This post is not hot at any time if wired correctly.


Tape the Relay and connectors secure with black electrical tape and tuck away down and under
(between large wire cluster and fire wall) under the ECM. The Main Junction Block is shown
located between the Battery and Fire Wall.



Summary of Starter Relay Installation on a 1990 and 1991 ZR-1

On the Early 1990s the wire to cut is RED (there is no 12 gauge purple wire)

Starter Relay, Wiring Harness, and Plugs Tricks

I locate the Relay UNDER the ECM which is right next to the wire harness/wire to be cut.

60 / 80 AMP RELAY SPDT SINGLE POLE DOUBLE THROW NEW 654
Installed under ECM and in slot between brake booster and fire wall (perfect place for location of Relay).

Wiring modified a bit to assure Pin #87a is not hot at any time.
Pin #30: Purple wire to starter (use 3/8 inch connector on relay).
Pin #87: Red wire battery positive 12v use 3/8 inch connector on relay (connected to battery positive multiple connection post).
Pin #86: Battery ground (1/4 inch connector on relay connected to ground where battery 12 gauge wire grounded).
Pin #85: Purple wire from Clutch Switch in wire bundle under the ECM use 1/4 inch connector on relay (Red wire on early 1990 ZR-1).
Pin #87a: Not hot at any time and not used.



3. Start Switch on 1990 (L98).

On my 90' (6 speed transmission) the clutch start switch linkage tab wore so I could not depress the clutch far enough to activate the starter selenoid. I finally (today) took a torch to it

I removed the clutch start switch just North of the steering wheel in line with the clutch pedal (corvette facing east). I also removed the linkage (about 2 inches long).

I heated the switch end of the linkage with a torch and straigtened out the first L (there are two Ls on that end). I then heated cherry red the linkage end again and created a new L making the straight part of the linkage effectively 1/8 inch shorter. Then reinstalled the clutch start switch and linkage.

Works great as I can now start the engine with the clutch depressed about 1/2 the way to the floor board.

Last UPDATE of post 53 Dec, 2017

Dynomite

Ignition Key Codes and Clearing 1990 INFL REST Codes

It appears if you have your own original key, you can for maybe a total under $30 buy a correct blank from MidAmerica (or Ebay) and go to WalMart and get that blank key cut as a spare key.

So....where can I get key blanks for $25?

MidAmerica http://www.mamotorworks.com/corvette?frame=1.1033

1. Key Codes.

Ohms-----------------------------------------------VATS Key Code #

402 ohms pellet----(acceptable range 386-438 ohms)----------1
523 ohms pellet----(acceptable range 520-564 ohms)----------2
681 ohms pellet----(acceptable range 650-728 ohms)----------3
887 ohms pellet----(acceptable range 850-942 ohms)----------4
1130 ohms pellet---(acceptable range 1085-1195 ohms)--------5
1470 ohms pellet---(acceptable range 1411-1549 ohms)--------6
1870 ohms pellet---(acceptable range 1795-1965 ohms)--------7
2370 ohms pellet---(acceptable range 2275-2485 ohms)--------8
3010 ohms pellet---(acceptable range 2890-3150 ohms)--------9
3740 ohms pellet---(acceptable range 3590-3910 ohms)--------10
4750 ohms pellet---(acceptable range 4560-4960 ohms)--------11
6040 ohms pellet---(acceptable range 5798-6302 ohms)--------12
7500 ohms pellet---(acceptable range 7200-7820 ohms)--------13
9530 ohms pellet---(acceptable range 9149-9931 ohms)--------14
11800 ohms pellet--(acceptable range 11328-12292 ohms)------15

2. Clearing 1990 INFL REST Codes.

For the 1991 through 1993 the Air Bag Sensors do not have to be grounded to work in a crash....they DO need to be attached to the Frame Rails however. The Grounding on the 1990 was set up to assure the sensors were attached to the Frame Rails. If the bolts were removed from the sensors the sensor would pass as air bag deployable but would not actually deploy the air bag for obvious reasons. This explains why I got NO INFL REST warning on the panel when I totally removed the 1991 Sensor from the Frame Rail in my test.

I am now thinking the Air Bag Sensors on the 1990 ZR-1 will function and Deploy the Air Bag even if not grounded. The 1990 Air Bag Sensors will only appear not grounded/not connected on the panel as INFL REST indicating/suggesting the Air Bag Sensors are not installed when in fact they ARE Installed. To get rid of that INFL REST Indication on the Panel (as well as the Red Seat Belt Indication) requires the Air Bag Sensors be Re-Grounded. I am not going to jar the Air Bag Sensor to see if the Air Bags Deploy to test that theory.

a. Make sure the ignition is off before you start.
b. Ground the ALDL Termal A to K. A is the grounding terminal BTW.
c. Turn the ignition on and wait for the INFL Rest light to start flashing (It should take about 5-7 Seconds).
d. When it starts flashing unplug the A-K for about 3 seconds then ground it again for an additional 3 seconds.
e. Remove and wait about ten seconds and ground it once more.
f. You should see a code 12 flashing 6 times indication the codes have been cleared and the DERM is operating normally (Dignostic Energy Reserve Module).
Note: The Fault Code Reader/Eraser described in the next post #55 can be used to Erase INFL REST Fault codes as described in steps a through f above by pushing a red button on the Fault Code Reader/Eraser. The SIR is NOT available using a Flash Code Reader on the 1994-1995 ZR-1s and The RED BUTTON is NOT used on the 1994-1995 ZR-1s.



Do Both Drivers Side and Passenger Side Accelerometer Sensor for Infl Rest.

Yep.....I just did this successfully on two 1990 ZR-1s. I used two alligator clipped leads and grounded A to K. I tuned the key on and watched the Infl Rest light disconnecting the leads from each other when the Infl Rest blinked....then one thousand 1, one thousand 2, one thousand three connecting the leads grounding A to K one more time and counting one thousand 1, one thousand 2, one thousand 3 disconnecting the leads from each other.

I did this several times and finally found my panel clear of the Infl Rest light once and for all.

And....the Seat Belt red indicator light on the panel also disappeared

3. Remove, Clean Contacts, and Re-Install Accelerometer Sensor for Infl Rest Codes (1990 ZR-1 ONLY).
Remove both right and left sensors and re-ground both then spray paint over each sealing the moisture access to the grounding surfaces.

For the Drivers side 1990 Accelerometer Sensor for Infl Rest Code 16.
Remove side panel. Leave tire and wheel well in place.
Remove Battery.
Remove battery platform (4 bolts and allows access to frame/sensor).
Remove Sensor (one 10 mm bolt and one 13 mm bolt).
Use Emory Cloth and sand contact surfaces on Frame Rail and Sensor
or best......use 1/4 inch drill with small (1 inch or 2 inch wire wheel).
Replace sensor (10 mm and 13 mm Bolts).
Spray Paint with Black Rustoleum all around sensor and sensor Bolts.

For the Passenger side 1990 Accelerometer Sensor for Infl Rest Code 26.
Remove the side panel. Leave tire and wheel in place.
Remove wheel well (rear of front wheel.....all 10mm bolts (three on slider, one below slider, two lower middle, one under wheel well)
Remove Windshield Washer Bottle (three 10 mm bolts).
Remove Sensor (one 10 mm bolt and one 13 mm bolt).
Use Emory Cloth and sand contact surfaces on Frame Rail and Sensor.
or best......use 1/4 inch drill with small (1 inch or 2 inch wire wheel).
Replace sensor (10 mm and 13 mm Bolts).
Spray Paint with Black Rustoleum all around sensor and sensor Bolts.

4. Details on how to remove Drivers Side 1990 Accelerometer Sensor.

Remove three Torx T-30 Fender Bolts. .....................Remove Top 10 mm Bolt holding Side Cover in place.


Loosen (do not remove) lower 10 mm bolt in the slot. ..The side cover will slide out of slotted bolt pad.


Remove the battery Hold Down Bolt (I modified that bolt with an 8 mm Allen Head Stainless Steel bolt).


Remove Battery Connections using 5/16 Flex Ratched Wrench. Remove two 10 mm bolts from Battery Platform.



Remove cable tie which is inserted in hole in plate securing bottom of Battery Platform.
Remove two lower 10 mm screws holding Battery Platform.


Remove second 10 mm screw using open end 10 mm wrench. Remove Battery Platform.



The INFL REST Drivers Side Sensor can be seen as it looks re-installed bottom of photo with 13mm bolt next to loose Lock Washer.

Temporarily remove the top assembly with the tip up red nozzle from a can of WD-40. Remove the white top spray nozzle from the top of a can of Black Rustoleum. Place the WD-40 top on the can of Black Rustoleum (it snaps perfectly in place identical to the top of a can of WD-40). Spray Black Rustoleum in those tight areas around the Sensor (Infl Rest Accelerometer) sealing the sensor contact areas in contact with the frame rail.



5. Clearing SIR Codes using the ALDL.
Ground K to A (I actually grounded K to the Seat Frame).
Turn on key to ACC
Wait for Infl Rest to flash and remove ground for 3 seconds. (I actually waited for the Code 26 (or code 16) to start flashing).
Re-apply ground for 3 seconds.
After removing ground wait 10 seconds.
Turn key off and remove ground to K.
Note: The Fault Code Reader/Eraser described in the next post #55 can be used to Erase INFL REST Fault codes as described in Item #2 steps a through f above by pushing a red button on the Fault Code Reader/Eraser. The SIR is NOT available on the 1994-1995 ZR-1s and the Red Button is NOT used on the ALDL Code Reader when using the Adapter for the 1994-1995 ZR-1.

6. If Codes 16 and 26 cannot be cleared on the 1990 ZR-1.....check the yellow Crash Sensor Connectors INSIDE the car.
AFTER Re-grounding the INFL REST Crash Sensors on both Left and Right Frame Rails the Code 16 could not be cleared until the Crash Sensor Connector Inside the Car was Disconnected and Re-Connected.

The air bag wiring is connected with a three pin yellow round connector (One on Drivers Side and One on Passenger Side). The Drivers Side is located just in front of Left Speaker at the same level as the top of the speaker. All you have to do is disconnect the Connector (round yellow plug type Connector with three pins inside) and reconnect the Connector. Code 16 goes away after resetting codes. The Yellow Plug Type Connector is about three inches long and 1/2 inch diameter. The same applies for Code 26 which yellow connector is on passenger side front floor carpet.

To Reset SIR Diagnostics Codes using ALDL connect A to K and turn key on. When you see INFL REST flash disconnect A to K for 3 seconds.....then reconnect A to K for 3 seconds then disconnect A to K.

Last UPDATE of post 54 Dec, 2017

Dynomite

ALDL Fault Code Reader/Eraser

The ALDL Fault Code Reader/Eraser Module can be plugged into the present ALDL Socket under the Drivers Side Panel. The ALDL Fault Code Reader/Eraser will ground the appropriate connectors of the ALDL when depressing and holding any of five Buttons depressed and turning the ignition key ON....(not all the way to START). The Fault Codes are flashed on the Panel just above the Bose Radio and the CCM Fault Codes flashed on the Speedometer Cluster. This ALDL Fault Code Reader/Eraser Module has a 12 Pin ALDL Connector which is compatible with 1990, 1991, 1992, and 1993 ZR-1s. An Adapter is available such that the 12 Pin ALDL Code Reader/Eraser can be used on the 94'-95' ZR-1.



To use.......connect the ALDL Fault Code Reader/Eraser to your ALDL Connector while sitting in the Drivers Seat (in front of your right knee) with Ignition OFF. Push/Hold Green, Yellow, Black, or White Button and then turn on Ignition (Do NOT start the engine). The Codes will Flash (Code 12 will flash for three times first followed by three flashes of each Fault Code) on the Panel just above the Bose Radio (ECM, SCR, ABS, SIR) and within the Speedometer cluster for the CCM.

1. ZR-1 12 Pin ALDL.
The ZR-1 Assembly Line Diagnostic Link (ALDL) pins are configured like so:



Pins F, -, -, J, L, and M are removed from the ALDL Molded Connector attached to the ALDL Fault Code Reader/Eraser as they are NOT used in this Application.
A Photo of the Five ALDL Fault Code Reader/Eraser Buttons is shown just below the Modified ALDL Molded Connector.



2. ZR-1 16 Pin ALDL.

An Adapter that connects to the 16 Pin ALDL ZR-1 Connector found on the 94'-95' ZR-1 with 12 Pin Connector on the other end that is identical to the 12 Pin Connector located on the 90'-93' ZR-1 has been developed. There are NO CHANGES in the EXISTING 12 Pin ALDL Fault Code Reader/Eraser when using the Adapter described here. The Adapter you can make yourself as described here as you like.

An Adapter that connects to the 16 Pin ALDL ZR-1 Connector found on the 94'-95' ZR-1 with 12 Pin Connector on the other end that is identical to the 12 Pin Connector located on the 90'-93' ZR-1 has been developed. There are NO CHANGES in the EXISTING 12 Pin ALDL Fault Code Reader/Eraser when using the Adapter described here.



Existing ALDL Code Reader for 90'-93'.........................ALDL Code Reader used with Adapter for 94'-95'



For the 16 Pin ALDL.......
Ground is Pin 4
Ground to Pin 6 is LTPWS/ECM
Ground to Pin 8 is PKE (Alarm System)
Ground to Pin 12 is CCM
Ground to Pin 3 is SRC


The 16 Pin Adapter has Pins 1 - 8 on bottom row from left to right as shown and Pins 9-16 on top row as shown.

So....in the adapter if I Connect the 16 Pin end to the 12 Pin end as follows:
16 Pin (94'-95')......12 Pin (90'-93')
Connect Pin 4 to.... Pin A [[B]Black Wire]
Connect Pin 12 to.. Pin G (White Button) [[B]Blue Wire]
Connect Pin 8 to.... Pin H (Black Button) [[B]White Wire]
Connect Pin 3 to.... Pin C (Yellow Button) [[COLOR="Red"]Red Wire]
Connect Pin 6 to.... Pin B (Green Button) [[COLOR="Yellow"]Yellow Wire]

Rear view of 12 Pin ALDL Connector.


Ebay Sources for 16 Pin OBD1 and 12 Pin OBD1 Connector
16 Pin OBD1 Connector
12Pin OBD1 Connector

We still have Pin K available (Red Button). So we could cover the CCM, PKE. SRC and ECM of the 94'-95' ZR-1 with the existing ALDL Code Reader as used on the 90'-93' ZR-1s using the Adapter.

3. ALDL Fault Code Reader/Eraser Buttons.
Green is ECM the one you are mostly interested in for Engine Issues.
Yellow SRC or Ride Control....FX3 shocks are Yellow.
Black is ABS....Wheels are Black.
CCM is White Elephant.....as the codes are read on the Speedo Cluster....
Red is SIR or INFL REST .......the HOT Button.....or the Button to check the Issues related to Safety (Not used on 94'-95').

A. ECM (SERVICE ENGINE SOON on Panel) Green Button.
B. SRC (SERVICE RIDE CONTROL on Panel) Yellow Button.
C. ABS (SERVICE ABS (PKE on 94'-95') on Panel) Black Button.
D. CCM (CCM Codes on Speedometer Cluster) White Button.
E. SIR (INFL REST on Panel) Red Button (Not used on 94'-95').

The ALDL Fault Code Flasher/Eraser Module has 5 colored mini switches (Push Buttons Close when depressed and held) mounted on a Billet Aluminum small block (5 inches x 1 inch x 3/4 inch) connected to an ALDL Connector (24 inch lead) that plugs into the ALDL under Drivers Side panel. All Buttons are Push and Hold completing the Grounding Circuit as long as the Button is Held.

4. ALDL Construction for ease of maintenance.
The Nut on each Button is to hold the Brass Washer in place. DO NOT tighten the nut more than finger tight. The purpose of the Nut is to also PULL the switch loose from the Aluminum Socket should it have to be removed. All switches and main line into the Aluminum Block are NOT GLUED for ease of maintenance such that the switches can easily be pulled from the Aluminum Block and the ground pin bent if the contacts have been moved in any way (The main line can be pushed into the Aluminum Block to provide slack for removal of the switches just in case a switch fails to ground the circuit provided).

There are 5 colored mini switches (Push Buttons) mounted on a Billet Aluminum small block connected to an ALDL Connector (24 inch lead) that plugs into the ALDL under Drivers Side panel. For the 94'-95 the Red Button is NOT used.

5. INFL REST appears on the Panel with engine running and does not go away.
A BIG thanks to Marc Haibeck for answering my questions regarding the SIR for 1990-1995 (The Red Button)

This from Marc.......
For the 1991 through 1993 the SIR Air Bag Sensors do not have to be grounded to work in a crash....the Sensors DO need to be attached to the Frame Rails however. The Grounding requirement (Code 16 and Code 26) of the Air Bag Sensors on the 1990 was set up to assure the sensors were attached to the Frame Rails. If the bolts were removed from the sensors the sensor would pass as air bag deployable but would not actually deploy the air bag for obvious reasons. This explains why I got NO INFL REST warning on the panel when I totally removed the 1991 Sensor from the Frame Rail in my test.

I am now thinking the Air Bag Sensors on the 1990 ZR-1 will function and Deploy the Air Bag even if not grounded. The 1990 Air Bag Sensors will only appear not grounded/not connected on the panel as INFL REST indicating/suggesting the Air Bag Sensors are not installed when in fact they ARE Installed. To get rid of that INFL REST Indication on the Panel (as well as the Red Seat Belt Indication) requires the Air Bag Sensors be Re-Grounded. I am not going to jar the Air Bag Sensor to see if the Air Bags Deploy to test that theory.

If any of the listed faults 21 - 26 for the 1991-1993 were detected in a self test the INFL REST will appear on the panel.

21 Steering Column Resistance Too High
22 Steering Column Resistance Too Low]
23 Steering Column Circuit Voltage Too High
24 Steering Column Circuit Voltage Too Low
25 Short to Battery in Steering Column
26 Open in Steering Column

Now for the 1994-1995 since two air bags are used has different codes and there is NO diagnostic terminal as indicated.
The design requires a TECH 1 diagnostics because the data is sensitive as a result of Government Regulations. On the 1994-1995 ALDL Code Reader when used with Adapter I have noted SIR diagnostics is NOT used. All other Codes are readable using the 94'-95' Adapter with the ALDL Code Reader.

Marc Haibeck ALDL Connector Functional Description

To Read the Fault Codes while sitting in the Drivers Seat......just plug the ALDL Fault Code Flasher/Eraser into ALDL and push/Hold Green Button for ECM (Yellow Button for SRC, Black Button for ABS, White Button for CCM, Red Button for SIR then turn the ignition switch ON (Do NOT start the engine) and see the Fault Codes flash on the Panel above the Bose Radio.

6. Fault Codes are Flashed on Panel above Bose Radio (except for CCM Error Codes) for the 90'-93' and 94'-95'.
All Codes (ECM, SRC, ABS, SIR) will Flash in Yellow on the Panel (90'-93') above Bose Radio when either the Green Button, Yellow Button, Black Button, or Red Button are depressed (turn the ignition key ON but do NOT Start the Engine). The ECM, SRC, ABS Fault Codes Flash on the Panel in Yellow and the Flashes must be counted to determine the Fault after an initial Digit 12 (One Flash followed by Two Flashes) is flashed three times for the ECM, SRC and ABS. An Example is the SERVIDE ENGINE SOON light which is always on when you are checking ALDL Fault Codes.

The CCM Codes will show on the Speedometer Cluster when the White Button is depressed and ignition key turned ON.
A CCM Code C12 indicates No Fault Codes are present.

For the '90-'93
ECM........................................ .....................................SERVICE RIDE CONTROL


SERVICE ABS ........................................ .....................................CCM Fault Codes


INFL REST


For the '94-'95 Using the adapter
LTPWS/ECM........................................ ............................SERVICE RIDE CONTROL


SERVICE PKE ........................................ .....................................CCM Fault Codes


7. How To Erase ALDL Fault Codes.
To Erase Fault Codes....Depress/Hold the appropriate Diagnostic Button and turn the Ignition Key ON....(not all the way to START). Wait for the Diagnostic light to start flashing for the Button Depressed. Release the Button for 3 seconds and then Depress/Hold the Button for about 3 seconds and Release. Turn the Ignition Key OFF.

To check that Fault Codes are Erased Depress/Hold the appropriate Diagnostic Button and turn the Ignition Key to On (do NOT Start the engine). The Code 12 should appear continuously indicating ALL Fault Codes are cleared.

8. How To diagnose the ALDL Fault Code Reader/Eraser.
Using an Ohm Meter, connect red wire to Pin A and black wire to Pin B. Do you get Zero Ohms when pressing Green Button.
Using an Ohm Meter, connect red wire to Pin A and black wire to Pin C. Do you get Zero Ohms when pressing Yellow Button.
Using an Ohm Meter, connect red wire to Pin A and black wire to Pin K. Do you get Zero Ohms when pressing Red Button.
Using an Ohm Meter, connect red wire to Pin A and black wire to Pin H. Do you get Zero Ohms when pressing Black Button.
Using an Ohm Meter, connect red wire to Pin A and black wire to Pin G. Do you get Zero Ohms when pressing White Button.
If zero ohms as indicated above, the Code Reader is reading correctly.



9. How To Obtain the ALDL Fault Code Reader/Eraser.
The ALDL Fault Code Reader/Eraser is $50 shipped anywhere in USA.
My PayPal is Dynomite07@prodigy.net
When you PayPal....let me know your Shipping Address and your Registry or CF ID in the PayPal Notes.

For those that are not regulars here....the ALDL Fault Code Reader/Eraser is also on CF ALDL Fault Code Reader/Eraser on CF.

See Last Post or close to Last Post for List of those Interested ALDL Fault Code Flasher/Eraser.

Those Interested (Reg and CF)
Paid-P, Shipped-S. Received-R
Kevin (PSR)
GOLDCYLON (PSR)
HAWAIIZR-1 (PSR)
93 Vette (PSR)
MysticZR-1 (PSR)
PhillipsLT5 (PSR)
diamond zr1 (PSR)
RussMcB (PSR)
G8nightman (PSR)
Scrrem (PSR)
Agpilot1 (PSR)
Andy (PSR)
Racinfan83 (PSR)
z proud (PSR)
Billy Mild (PSR)
LT5Vette (PSR)
FI250 (PSR)
BlackZR1 (PSR)
edram454 (PSR)
George Maz (PSR)
32valvesftw (PSR)
spork2367 (PSR)
txtode (PSR)
jmglyder (PSR)
Geezer (PSR)
jrd1990zr1 (PSR)
KFoster (PSR)
Halinmontana (PSR)
KGV (PSR)
IMZZ (PSR)
steve1263 (PSR)
MuRCieLaGo (PSR)
Intruder (PSR)
goriffle (PSR)
rush91(PSR)
Xdt (PSR)
Chedberg(PSR)
apbreg(PSR)
G-Sting (PSR)
Johnny5 (PSR)
garyhugo (PSR)
Dds1990 (PSR)
jcruz (PSR)
ZR71Blackbird (PSR)
max76 (PSR)
TX '90 ZR1 (PSR)
NJVII (PSR)
Dustin Koppit (PSR)
Marshall Neel (PSR)
mrimd (PSR)

Each ALDL Fault Code Reader/Eraser shipped will include ALL the information shown in the ALDL Fault Codes Thread.

Note: A Code 12 indicates No Fault Codes are present with the exception of the SIR.

SIR Code 13 will be displayed (In addition to Code 12) only if no history codes are in memory. To read history codes, a SCAN/TECH tool must be used. Read more: The Seat Belt Question

See Fault Codes and post any questions regarding any Fault Codes in the Fault Codes Thread as that is a great question regarding the SIR Codes.

Last UPDATE of post 55 Nov, 2020

Dynomite

1. ZR1 ABS Code - Definition

1990 Service Manual:

(* = Requires Tech 1 Daignostic Tool)

12 - Diagnostic System Operational

21 - RF Wheel Speed Sensor Fault
22 - RF Toothed Wheel Frequency Error
25 - LF Wheel Speed Sensor Fault
26 - LF Toothed Wheel Frequency Error

31 - RR Wheel Speed Sensor Fault
32 - RR Toothed Wheel Frequency Error
35 - LR Wheel Speed Sensor Fault
36 - LR Toothed Wheel Frequency Error

41* - RF Solenoid Valve Fault
45* - LF Solenoid Valve Fault
55* - Rear Solenoid Valve Fault

61* - Pump Motor or Motor Relay Fault
63* - Solenoid Valve Relay Fault
71 - EBCM Fault
72 - Serial Data Link Fault

75 - Lateral Accelerometer Fault (Short to B+ or Ground, or Open Circuit)

76 - Lateral Accelerometer Fault (Signal Out of Range or Incorrect)

Clearing Codes

The fault codes in the EBCM's memory are erased in one of three ways:

1. Diagnostic Enable Line Procedure
2. Tech 1 "Clear Codes" Selection
3. Igniton Cycle Default

Whichever method is used, be sure to verify proper system operation and absence of codes when clearing procedure is completed.

2. ZR1 Ride Control (SRC) Codes.
12 = Start of sequence
13 = Left rear time out
14 = Right Front time out
21 = Left Front time out
22 = Right Rear time out
31 = Left Front out of position
32 = Right Front out of position
33 = Left Rear out of position
34 = Right Rear out of position

Out of position codes are triggered if the computer senses that the actuator has not found the end stop position on the shock. Remove actuator at the indicated shock. Turn the valve gear on the shock stops after about 3 / 4 of turn, then you have a bad actuator. If it spins around continuously then it is a bad shock

41 = Selective ride control switch short to voltage
42 = Selective ride control switch open contacts
You can have a code 42 if you leave the switch in between indented positions
43 = selective ride control switch circuit open.

23 = If you start the car more than 3 times and do not move the car this code will set. Drive 3-6 feet and the light will go out.

The ride control controller is located in the bin behind the drivers seat mounted with the ABS controller.

3. ZR-1 CCM Codes
Code Definition
1.1 DISPLAY CCM fault codes
12 On-board diagnostics no codes (this is a good thing: no problem found)
13 DIC switches open or shorted to battery
14 DIC switches shorted to ground
16 Ignition 3 fuse circuit open
21 Horn relay coil shorted to battery or CCM internal open circuit
22 Rear defogger relay coil shorted to battery or CCM internal open circuit
24 Courtesy lamp relay coil shorted to battery or CCM internal open circuit
25 Courtesy lamp relay coil circuit open or shorted to ground
26 LCD blanking control circuit shorted to battery or CCM internal open
27 LCD blanking control circuit open or shorted to ground
31 LCD data circuit shorted to battery or CCM internal open
32 LCD data circuit open or shorted to ground
33 Data clock circuit shorted to battery or CCM internal open circuit
34 Data clock circuit open or shorted to ground
35 Data strobe circuit shorted to battery or CCM internal open circuit
36 Data strobe circuit open or shorted to ground
37 M clock circuit shorted to battery or CCM internal open circuit
38 M clock circuit open or shorted to ground
41 Loss of ECM serial data communications
51 Pass-key invalid key detection
52 Pass-key key detection circuit shorted
53 Pass-key – key detection circuit open or shorted to battery
54 FEDS fuel enable failure
61 Pass-key – key #1 programming resistance out of range
62 Pass-key – key #2 programming resistance out of range
63 Pass-key – key #2 programming resistance low
71 LCD dimming output circuit shorted to battery or CCM internal open circuit
72 LCD dimming output circuit open or shorted to ground
73 LED display dimming output circuit shorted to battery or CCM internal open circuit
74 LED display dimming output circuit open or shorted to ground

4. 1990 SIR Codes
For 90-93 Cars jumper A to K on the ALDL and the INFL REST light will flash

1990 SIR Codes
14 Front Sensor #1 (LH); Short to Ground
15 Front Sensor #1 (LH); Open Circuit
16 Front Sensor #1 (LH); Sensor Fault
24 Front Sensor #1 (RH); Short to Ground
25 Front Sensor #1 (RH); Open Circuit
26 Front Sensor #1 (RH); Sensor Fault
31 Inflator Squib; Current leakage to Battery
32 Inflator Squib; Current shorted to battery voltage
33 Inflator Squib; Current leakage to ground
34 Inflator Squib; Current shorted to ground
35 Inflator Squib; Open circuit
36 Inflator Squib; Squib fault
41 Indicator lamp circuit; Shorted to battery or ground
42 Indicator lamp circuit; Open circuit
51 Diagnostic unit faulty
52 Firing sequence confirmation set
53 Firing current confirmation set
54 Squib current has flowed

5. 91 & 92 & 93 SIR Codes
21 Steering Column Resistance Too High
22 Steering Column Resistance Too Low
23 Steering Column Circuit Voltage Too High
24 Steering Column Circuit Voltage Too Low
25 Short to Battery in Steering Column
26 Open in Steering Column Circuit
31 Open 36 VLR to Deployment Loop
32 Grounded 36 VLR to Deployment Loop
33 Diode B Shorted in Wiring Harness
34 Open in Ignition 1 Feed to Deployment Loop
35 Discriminating Sensor Open
41 Deployment Loop Energy Reserve Voltage Fault
42 Deployment Loop Energy Reserve Voltage Fault
51 Accident Detected
52 EEPROM Accident Data Area Full
61 Force Low or “INFL REST� Warning Lamp Circuit
71 Internal DERM Fault

6. 94 & 95 SIR Codes
For 94-95 Cars, jumper Terminal 4 to 12 on the ALDL and enter the CCM diagnostics, or use a Tech1

14 Dual Pole Arming Sensor Disconnected
15 Passenger Initiator Circuit Resistance High
16 Passenger Initiator Circuit Resistance Low
17 Passenger Initiator Circuit Open
18 Discriminating Sensor Interconnect Open
19 Passenger Initiator Circuit Voltage High
21 Driver Initiator Circuit Resistance High
22 Driver Initiator Circuit Resistance Low
23 Driver Initiator Circuit Voltage High
24 Driver Initiator Circuit Voltage Low
25 Initiator Circuit Short to Ignition
26 Driver Initiator Circuit Open
28 Current Sink or Source Failure
31 Driver Loop Energy Reserve Feed Open
34 Dual Pole Arming Sensor Ignition Feed Open
35 Discriminating Sensor Open or Missing
36 Passenger Loop Energy Feed Open
42 Loop Energy Reserve Volatage Low
43 Driver Source Feed Low
44 Passenger Source Feed Low
51 Frontal Crash Detected
52 Data Area Full
53 Driver Side Low High Resistance
54 Passenger Side Low High Resistance
55 DERM Incompatibility
61 SIR Indicator Circuit Failure
62 Redundant Indicator Circuit Failure
71 and or 75 Internal DERM Fault
81 Driver Ignition Diode Open
82 Passenger Ignition Diode Open
83 Driver Reserve Diode Shorted
84 Passenger Reserve Diode Shorted

Last UPDATE of post 56 Sep, 2015

Dynomite

1. ZR1 90'-95' ECM Interchangeability'

2. CODES 90' TO 92'.

Code #12: Normal No Codes.
Code #13: Left Oxygen Sensor Circuit.
Code #14: Coolant Temperature Sensor Circuit High.
Code #15: Coolant Temperature Sensor Circuit Low.
Code #16: Direct Ignition System (DIS) Fault Line Circuit
Code #21: Throttle Position Sensor Circuit High.
Code #22: Throttle Position Sensor Circuit Low.
Code #23: Manifold Air Temperature Sensor Circuit Low.
Code #24: Vehicle Speed Sensor Circuit.
Code #25: Manifold Air Temperature Sensor Circuit High.
Code #31: Camshaft Sensor Circuit.
Code #33: Manifold Absolute Pressure Sensor Circuit High - Low Vacuum.
Code #34: Manifold Absolute Pressure Sensor Circuit Low - High Vacuum.
Code #36: Direct Ignition System (DIS) Circuit (missing or extra EST signal)
Code #41: Cylinder Select Error (Faulty or Incorrect Mem-Cal)
Code #42: Electronic Spark Timing (EST) Circuit.
Code# 43: Electronic Spark Control (ESC) Circuit.
Code #44: Left Oxygen Sensor Circuit Lean.
Code #45: Left Oxygen Sensor Circuit Rich.
Code #46: Vehicle Anti-Theft System (VATS)(PASS-Key) Circuit.
Code #51: Mem-Cal Error.
Code #52: Engine Oil Temperature Sensor Circuit Low.
Code #53: System Voltage.
Code #54: Fuel Pump Circuit (Low Voltage)
Code #55: System Voltage
Code #56: Vacuum Sensor Circuit.
Code #61: Secondary Port Throttle Valve System.
Code #62: Engine Oil Temperature Sensor Circuit High.
Code #63: Right Oxygen Sensor Circuit Open.
Code #64: Right Oxygen Sensor Circuit Lean.
Code #65: Right Oxygen Sensor Circuit Rich


3. ECM Related Explanations.

31 LCD Data Circuit-Circuit shorted to battery voltage or CCM driver open
33 Data Clock Circuit-Circuit shorted to battery voltage or CCM driver open
35 Data Strobe Circuit-Circuit shorted to battery voltage or CCM driver open
37 M Clock Circuit-Circuit shorted to battery voltage or CCM driver open
72 LCD Dimming Open Circuit-Circuit open or shorted to ground (radio & Climate control)
H History code. May be intermittant.
Code 31, 33, 35 related to the circuit from the CCM to the Instrument panel LCD.
CCM 74 is also a lighting circuit problem.
CCM 41 is loss of communication with the ECM.

4. ECM Code #52 Engine Oil Temperature Sensor Circuit Low Explanation

The Oil Temperature Sensor Terminal B or circuit B discontinuity would prevent Full Power operation it would appear.

"When the key is in “Full” power position, the ECM enables the secondary operation only if no trouble codes are stored and other criteria are met such as; engine oil temperature (not too hot or too cold)."

Basic Conditions that allow Secondaries to open:
"In order for the Secondary Port Throttle Valves (Secondaries) to open, the following parameters must be met:

Coolant Temperature 20 Deg C (68 Deg F) or above
Oil Temperature 20 Deg C (68 Deg F) or above See ECM Code #52 Item #3. ZR1 ECM CODES 1990 TO 1992
System Voltage 10 V. or above
Trouble Codes (SES Light) None
Power Key On"



Last UPDATE of post 57 Dec, 2017

Dynomite

1. R12 compared to R134a.

Now since I have R12 Adapters and R12 I (and my EPA certified technician) are ready for 90' and 91' (LT5) and 90' Corvette (L98) if they ever need an AC boost for almost nothing additional over what I have for an older Toyota and GMC AC system.

R12 and E134a Connectors.
I know the Connector for R12 is different than the Connector for R134a.
On the Can end as well as on the AC end.

Freon R12 and R134a Adapters


R12 Engine End ........................................ ..........R12 Can End


R134A Engine End........................................ ........R134a Can End


Adapter Connections R134a to R12.................................R12 Can Connector and Gauge


2. Vacuuming an R12 System and installing a New Drier.

The technical information in this post is provided by VetteVet VetteVet How To Evacuate and Re-Charge A/C System on C4 ZR1.

I have a vacuum pump with an R12 fittings (actually two fittings) and a set of gauges (red and blue) with R12 adapters. I also have a new Accumulator/Drier (not installed yet as I assume I do not want to expose that to air). Have a few cans of R12 and a couple cans of R12 plus oil.

Vacuum the A/C System and check for leaks.
1. The A/C connector on the passenger side with black cap (just inside of shock) is High Side.
2. The A/C connector on the Accumulator/Drier is the Low Side.
3. Connect gauges to the Vacuum Pump (yellow line center of Manifold).
4. Connect Low Side (Blue Line) to Accumulator/Drier connection.
5. Connect High Side (Red Line) to High Side connection just inside passenger wheel well (lower line on Evaporator Housing).
6. Open both High Side and Low Side Manifold Valves and turn on Vacuum Pump for 60 minutes.
7. Shut Manifold Valves (then shut OFF Vacuum Pump) and make sure Vacuum does not leak down indicating a System Leak.
8. If NO LEAKS, Install New Accumulator/Drier and repeat this process.

A/C Connections for Vacuum and Leak Test System....Vacuum System Setup with Vacuum Pump Connected


Stage Vacuum Pump........................................ ..........Manifold and Gauges


ZR-1 R12 Freon Connector (Low Side)..........................Accumulator/Drier


3. Charge the A/C System.
1. With both Manifold Valves closed, hook up a can of R12 to the yellow middle hose (see Note #1 below).
2. Turn the can valve fully counterclockwise to open the valve.
3. With the can upright, crack the fitting on the yellow hose where it attaches to the gauge manifold to purge the air out of the hose, then retighten it.
4. You can now invert the can and crack the blue Low Side valve and charge until the pressure equalizes between the can and system (no more flow is felt or heard). Never open the Red High Side valve during the Freon Charging process.
5. Now start your car and set the climate control for Max cooling with blower on high. Ensure that the compressor clutch is engaged at this point (see Note #2 below). You can now charge the remainder of the first can with can in an upright position. Always charge with can upright when compressor is running.
6. Once the first can is in, (you'll know it's all in when you can shake the can and not feel any liquid sloshing in it) you can shut the low side valve and swap to the second can.
7. Remember to purge the yellow line again prior to charging.
8. Continue this until you have added the correct amount of Freon, per the FSM. Once the sytem is fully charged, shut off the compressor and allow High Side and Low Side pressures to equalize before disconnecting the gauge manifold from the system.
9. Once the manifold is disconnected, cap the high and low side fittings, reconnect the pressure cycling switch and you're done.

Notes:
1. Prior to connecting the valve to the freon can, unscrew the valve stem fully(you will see the needle in the valve retract up into the body). Then screw the valve onto the can. Now turn the valve fully clockwise to puncture the can.
2. If the compressor clutch is not engaged, you will have to pull the connector on the pressure cycling valve in the low side line and jumper it. The compressor clutch should now engage.
3. The better you vacuum the system, the better it will perform. You won't hurt the vacuum pump if you want to let it run for 5 hours.
4. Always purge the air from the charging(yellow) line when you connect a can of Freon.
5. When the compressor is running, always charge to the low(blue) side with can upright.
6. NEVER, EVER open the high side valve when the compressor is running. That flimsy Freon can will not contain the pressure(can you say SHRAPNEL!!!). I've never done it and don't want to try.
7. If you follow these Notes, no harm will be done.
Thank you VetteVet (Jep) for the "How To" including these Notes.

4. AC Cycling Switch.

Check your AC cycling switch. Disconnect the AC Cycling Switch connector and with engine running and AC on see if you have 12 volts to one side of the connector. Then measure the resistance between the two pins of the AC Cycling Switch. If there is NO resistance and you have 12 volts to one side of the connector your compressor clutch should engage.

If you do not have zero resistance between the two pins of the AC Cycling Switch you either have not enough Freon in your system or a bad AC cycling switch. I am thinking with 65 psi on the low side with engine off the AC Cycling Switch should be on (Connectors/points closed or zero resistance between Connectors/points).

I am thinking the cycling switch should turn off at 25 PSI (compressor clutch disengaged), and back on at 40 PSI (compressor clutch engaged) low side pressure. I am thinking greater than 400 psi on the high side will turn off the compressor (disengage compressor clutch).
See AC Normal Low and High Side Pressures TIPS

It is my understanding that moisture gets trapped in the oil (compressor lubrication) and you have to pull a significant vacuum to rid the oil of moisture. It is also my understanding that the Accumulator/drier should always be replaced if you open up the AC system to atmospheric pressure.

Make sure one Female Contact of the AC Cycling Switch Connector has 12 volts with Key On and Air On.
The AC Cycling Switch on the Low Pressure Side of the AC System is shown in the background in this photo. With engine running, the shorting across the connector should engage the AC clutch if the AC compressor is functional.



Last UPDATE of post 58 Dec, 2017

Dynomite

1. Crankshaft Sensor Testing/Replacement by Alberta ZR1.

I figured I would do a quick write up on my recent no start concern with my 93. The engine would turn over but would not fire and it turned out to be the crankshaft sensor.

There were no codes during the final failure of this part and I was having the following symptoms prior to complete no start failure.
A.) The car had a hard time starting when it was hot
B.) The car quit for no reason when driving, but would re-fire after extended cranking
C.) The car finally quit and would not start again

If you run into a similar situation where the engine turns over, but does not fire, there are few things to consider before looking at the crankshaft sensor. However in my situation, when I was doing the preliminary checks, I determined that all my other systems were working correctly, and I simply had no spark.

Crankshaft Description (As noted in 1993 GM Service Manual)
The magnetic crank sensor is used to determine engine crankshaft position. The sensor is mounted inside the block near a nine slot wheel on the crankshaft. The rotation of the wheel creates a flux change in the sensor which produces a voltage signal. The ignition control module processes this signal and creates the reference pulse needed by the ECM to trigger the correct coil at the correct time.

Step1: Removed the crank sensor connector/harness from ignition control module and probed terminals A and C on the connector of the wiring harness with an ohm meter. You are looking for a reading of 800-1200ohms. I had an open circuit indication.
(Note: To access this sensor, you need to remove the MAP sensor and bracket as well as the PCV hoses from behind the intake.)




Step2: The FSM says less than 800ohms means the sensor leads have shorted together or the sensor is faulty. If you have a reading greater than 1200ohms, there there is an open sensor circuit or faulty connection at the sensor, or faulty sensor.

Step3: Since the crankshaft sensor is so inconvenient to get to, I decided that I would purchase a new one to replace it with since I would be under the car anyways. I went to Napa and picked up the sensor (Part# CSS109)



Step4: As soon as I attempted to remove the sensor, the head broke off leaving the rest of the sensor inside the engine block. I attempted to extract the remaining piece of sensor with epoxy and a bolt, a screw, and o-rings piks. The sensor would not move, so I ended up having to drop the oil pan and punch the sensor out from the inside.

Step5: After replacing the sensor and buttoning everything up, the car started and all systems checked out!



2. Camshaft Position Sensor Failure by Marc Haibeck.

"The Camshaft Position Sensor has a very low failure rate. I have replaced about three bad ones in 20 years. After a lot of exposure to heat it can leak oil due to a crack in the case. However, leaky ones continue to operate correctly.

The most common cause of a code 31 is a worn out battery not filtering electrical noise as it should. A defective crankshaft sensor can cause a false code 31. The ECM can fail and cause a false code 31.

The engine will start and run normally with the Camshaft Position Sensor disconnected. It is used for emissions purposes.

They are very hard to find. It's a simple Hall Effect sensor.

Marc"

P.S. Jagdpanzer on the ZR-1 Registry Forum has built a successful Replacement Camshaft Position Sensor Replacement Camshaft Position Sensor

Last UPDATE of post 59 Dec, 2017

Dynomite

BOSE Speaker Amp Options for 1990 and 1991 ZR-1

Thanks Mike
I picked up some more 975 Bose Amps from 1995 96 97 98 99 Nissan Maxima and Infiniti I30. I also picked up some 075 amps which also work from Nissan Maxima and Infiniti.

I just disconnect this connector (shown in photo) and plug and Play New (used) Amps into the 1991 ZR-1 (the 1990 ZR-1 has soldered connectors on the Bose Amp so have to get the pigtail with white connector for 1990 ZR-1s)....they ALL sound great (I have 975 Front and 975 Rear).

Just be careful you do not break two little white tabs on the Amp that catch and hold the Connector in place. You can usually wiggle the plug loose without breaking the tabs.

Doctor Don has extra Pigtails with connector and wire harness plug on other end for $5 (the short wire harnes that is mounted on the speaker frame attaching the Amp to the ZR-1 wire harness (two different lengths for Front and Rear the Front being longer).



I now have more amps (975s and 075s) which both work plug and play perfectly in the ZR-1. The 928s and 984s do NOT function in a ZR1. You can plug either Front or Rear Amps in the ZR-1 rear speaker board for testing and yes....there is a bit different tuning as Mike pointed out. What you are really looking for is the 1995 96 97 98 99 Nissan Maxima and Infiniti I30. Just make sure you are pulling a 975 (Front and Rear) Amps.

The 1995 96 97 98 99 Nissan Maxima and Infiniti I30 Front and Rear Bose Speakers PAIR Sigma 975' look like this.....

1995 96 97 98 99 Nissan Maxima Front Speakers..........1995 96 97 98 99 Nissan Maxima Rear Speakers


To Remove the Front Amps On the Maxima...
1. Remove three bottom phillips screws on door panel.
2. Remove little button in bottom of ash tray and remove that phillips screw.
3. Pop out ash tray.
4. Pop out side of door panel as the sides are held in with plastic expanded plugs which pop loose.
5. Remove trim around door latch and pull out trim a bit so it does not get caught on door latch.
6. Lift door inner panel and remove...there are some electrical wires but you can now set the door panel aside.
7. Remove the four small phillips screws on the Amp Cover.
8. Slip the amp out and disconnect the amp electrical connector shown above.

To Remove the rear Amps On the Maxima...
9. In the trunk.....remove three small 7 mm head screws from plastic cup tabs holding Amp under speaker.
10. Disconnect electrical plug from cup or cut electrical wire.
11. Remove 4 small phillips screws holding the Amp inside the cup.
12. Disconnect the electrical connector shown above but make sure you do not break the two little plastic latches holding the plug in place.
13. Most the time you can just wiggle the plug and the plug will come free without breaking the latches.
14. If the rear glass is broken out.....just remove the 4 phillips screws holding the speaker down and lift the speaker up and out with the plastic cup attached.

When at Pick UR Parts
All one needs is a bucket for the amps and three or four tools.

A nice small shaft (and one larger shaft) phillips screw driver, a medium flat head screw driver, a 1/4 inch socket wrench (with 3 inch extension) with 1/4 inch socket, 7mm socket (maybe a 6mm socket) and a small electrical wire cutter just in case.

Oh....and do NOT call the Amps ....AMPS as they have a listed parts prices and Amps are more expensive meaning the main audio Amps.
Call the Amps switches or Tuners.....and offer $5 for each (you definitely should not pay more than $9 each) as they are not a HOT item ....UNTIL NOW....

Just ran into an experience where the Pull UR Parts gal wanted $22 for Nissan Maxima Speaker Amps.....when in fact the whole speaker with Amp (Amp is part of same plastic speaker case) would cost $16. Then she called the Amp a Relay and Relays cost $19. I explained that several of the Amps came from cases in which the speaker was already taken. I left that place with their Amps on the counter. Went down the street (competitor Pull UR Parts) and explained several of the six Amps I found at that Pull UR Parts came from cases with no speaker.....Amps cost $5.50 at the Pull UR Parts down the street





Oh......There are no more 975 Bose Speaker Amps in Fresno.

Thank You mike100 for that Superb Information on ZR-1 Speaker Amps.

NOTES:
Background Diagnostics Information.

Did the sound deterioration start all at once?
Do you get any sound at all?
Did this happen on all four speakers at the same time?
Does it happen with CD as well as AM/FM?

I usually start at the speaker amps (exchanging Nissan Max 975s or 075s).
If one speaker amp exchange for a known good amp does not work...then Bose or CDM.

Last time I had issues I exchanged Bose for a known working Bose....found I had no sound after switching in a good Amp and good Bose. So exchanged CDMs and got all the sound back in great order.

If you have someone near by with a good Bose....it is about a 10 minute job to exchange a known working Bose for your Bose.

Same goes with amps....use the rear drivers side amp and exchange that for a known good amp.

Start with the easiest replacement and that be an amp....then the Bose.

Now if nothing as suggested above works.....have fun removing and exchanging the CDM

See Bose Speaker Amps and CDM Replace

The usual problem with Bose is the CD player does not take and run a CD.....that is Doc Dons department.

Last UPDATE of post 60 Apr, 2018