1Harley 1Vette

96 CE Vert.
Driving to work this morning on the highway the Vette just died at 65 MPH. I was able to put it in nuetral and coast off the road. $101 tow to a local Mechanic. He diagnosed it as having a Leaking water pump at the weep hole and a bad Opti. Now I just replaced the water pump and Opti several months ago. The car will start when its cool and after it runs for awhile it will spit and sputter and die. No visible anti-freeze leaking.The mechanic wanted $1200 for a new WP and Opti so I brought the vette home. I was able to drive it about 3 miles to get it home. I pulled the codes and was hoping to poll the forum on what I should look at before I rip out the water pump and OPTI again. Thanks for all your advice!

CODE: p1371-MANUFACTURER CONTROL IGNITION SYSTEM OR MISFIRE

CODE: P0372-TIMING REFERENCE HIGH RES SIGNAL A TOO FEW PULSES

Please help in directing me where do I go from here. Thanks. Gary

Railroadman

I don't have the answer but I think you did right by bringing it home until you're sure what the problem is. $1200 for WP and opti isn't something you do for the process of elimination only to find it's something else.

"No visible anti-freeze leaking" - hmmmmm.....is your coolant level OK? If it is, I'd question his diagnosis.

Good luck with it - someone here will have an answer. Let us know what it turns out to be so we can learn from it.

jonecap

Unfortunately, those are the exact same symptoms I had when my opti was bad. Put a MSD opti on it and don't worry about it anymore.

You might pull your opti and take it apart to make sure the optical wheel did not come lose. What type of opti did you put on it previously?

MMOCguy

I have a '93 and mine just died on me one day after I pulled into my garage. It turned out to be the ignition control module. They are a lot cheaper than a new opti-spark and water pump.

I believe that Kragen (AKA Checkers) has a relative imexpensive module for under $100.

I have Chilton manual and it gave me the troubleshooting sequences to isolate the problem. It took me right to the ignition control module.

I hope that this helps.

Norm.

jimg's'93

Does she still start? If so, I'd think you either have some severe arching or a coil/ICM overcome by heat.

If she doesn't start, then I'd be looking for signal at the test connector on the plenum, A good FSM helps

nobull66

I have a 93 and mine did the same thing on the highway it was the ignition control module.

93cruiser

I agree. Same thing happened to me.
93cruiser

merlot566jka

yeah, sounds like ignition control module or fuel pump. both typically fail due to heat, and will most of the time allow the car to restart and run until they warm up again.

test fuel pressure when the car dies
test spark when the car dies
test icm signal and spark output when the car dies.

you need three things for the engine to run; air, fuel, and spark. test and see which you dont have once the car dies. then troubleshoot further.

you need to duplicate the problem, so keep testing tools in car and make laps up and down your street and let it idle to get warm.


when my opti failed on my 2nd c4, it was noticed as a slight miss at idle and horrible misfires at wot and anytime the engine was under load. but it never died while driving.

and since you have the car, and obviously not going anywhere, its relatively cheap to pull the opti out and verify that it hasnt had coolant spray onto it. (if the weep hole was only dripping at higher rpm, it could have just sprayed right back onto the opti, but never left a drop on the ground). This would confirm the mechanics diagnosis as truth or assumption. Even though you just replaced the water pump and opti doesn't mean they wont fail again. Ive had brand new parts out of the box fail.
At the same time, I could think of better ways to spend 2 hours! If the opti is fine, you just narrowed down one part of the equation, at the cost of your time. I know my time is a lot cheaper than some other mechanics!

Suspect everything, test everything, find the problem, then buy parts to fix it.


(disregard the lack of capitalization and grammatical errors, I've been up for 40 some odd hours!)

TWISTERUP

I'd check the opti harness at both ends for corrosion and a good connection--but the high resolution code-- too few pulses sounds like the opti. I had a fairly new Accel opti fail (no start) on the highway with a high resolution code. The rotor screws were not loctited which allowed the trigger wheel to work loose and chew up the opti decoder. My 2 cents

Warren Seale

It is not detecting the high res timing pulses. When this happens the engine will run open loop (cold) but when it gets to operating temperature, the ECM needs to have those timing pulses. If it doesn't get them it shuts off the fuel pump and the engine goes kaput. This is all due to the optical sensor module in the optispark going bad. Do you have a Chinese knock off Opti? If yes, they are known to have optical sensor modules that fail early.

Warren

Matthews1stvette

From what Ive been told what makes your optispark go usually is the water pump leaking on it so both will have to be replaced. I had to do it. I got mine done at chevy dealer and it was cheaper than 1200 bucks.

1Harley 1Vette

Thanks for all your replies and please keep them coming. Is there a way to test the ICM after I remove it. Can Autozone test it? They have one for $80. If thats not the issue then I guess I will look towards the Opti.

TWISTERUP

Places like autozone--advance auto should be able to test --however sometimes the ICM cools off enough on the trip to the parts store they test good even though it has a problem hot. I suspect you'll be replacing the opti though, because I've never seen or heard of a ICM throwing a "high resolution" code.

onedef92

Check your coil and ignition control module (ICM). Both parts are cheaper (and easier to replace) than an Opti/water pump combo.

When my 'Vette flat-bedded me, it was caused by a bad coil, which took my ICM out with it. Immediate crank, no-start condition. I replaced the coil and ICM and it fired right up and ran like new money.

SwagonS

A friends neighbors vette died a month after he had a chinese opti put in. His ace Mech told him he needed an ECM, Fuel Pump and something else because his scanner told him so. We went over there rigged an "external opti" and got the car to fire. Replaced the opti and no probs since. Don't always trust the scanner.

1Harley 1Vette

OK so my cheep knockoff Opti must be the problem. If it is the Opti can I replace it with a Delphi from Napa or should I go with the MSD for $300 dollars more. It's a daily driver so high performance is not top priority. Dependable performance is a must. I will get the Delphi water pump replaced at no charge since it's still under warranty.Thanks

TWISTERUP

Delphi made the OEM optis for GM--seems to me like someone has a good or bad story about every brand out there. My last one was a Delphi which I bought from the "partsladi" on ebay---good price

kimmer

Had the same thing happen to me and it was the icm, got one at autozone and it is warrented for life, was about 80 bucks. I have a 92 and they could not test mine. Since I had that out I replaced the coil , its real cheap.

1Harley 1Vette

OK Folks, heres the update. I replaced all of the following with "NEW" Parts. Napa Water Pump, ACDelco Opti, Napa Coil and Napa Ignition Control Module. When I went to start it it would not start at all. I checked for spark and had NONE. I reconnected the old ICM and it would not start. I reconnected the old coil and it would not start. I reconnected the new coil and ICM and it started up. I started it in the garage and let it idle to normal operating temperature on 3 seperate occations over 3 days without it dieing. Last night I drove it for about 20 minutes around the neighborhood and it died. I reseated the ICM connection and still no start. I reseated the coil connection and still no start. After about 5 minutes of sitting, it started and got me home. NO CODES present. I am assuming since there was no spark after the original install that there was no spark last night but I could not prove it on the road. I am going to purchase an in-line spark tester tonight so I will be able to verify. I don't think it would be a fuel pump if I have no spark. Is that correct? I did purchase the 2 book set FSM on EBAY yesterday so I'm waiting for that to come in.

Any new advise would be greatly appreciated. Thanks

One more thing. When it Dies, It Dies. No sputtering or nothing. It just flat out quits.

aminnich

Check the short harness for the opti that runs under the pass side fuel rail cover. It gets brittle from engine heat and any poor connections can cause what you are experiencing.
Hope this helps.