Tom454

Replaced Fuel Injectors (needed- they were leaking)
Replaced & Adjusted TPS (needed- it was intermittent)
Replaced Plug Wires (needed- they were melted)
Removed Cold Start Injector (just because it might be leaking)
Replaced Plugs (had wrong plugs)
Replaced Rotor
Replaced Distributor Cap
Replaced Timing Chain & Gears (needed- totally shot)
Rebuilt Fuel Pressure Regulator
Replaced IAC (made a slight difference.. was not adjusted correct
1-3/16)
New IAC set to 1-1/8" pintle depth
Distributor blueprinted (includes shimming endplay)
Fuel Pressure is correct
Timing Set

Not touched:
MAF
Ign Control Module
Distributor Module
ECM/ECU

It was difficult to start but ran "okay" when warm before I started all of this.

Now:
Won't start when hot
Won't run above 1800 rpm (misfires/shakes)
Won't idle below 900 rpm (stalls)

Oh.. I also purchased the Moates cables and ProTumer 5 and can't get it to work so I gave up on that.

I see a carburetor in my future..... LOL

Can I temporarily drop in a 1 wire HEI distributor (Accel 59107) to see if it eliminates the rpm issues? I.E.- will the ECM be able to control the injectors etc. without a factory distributor installed?

Kevova

You will need to stay with a TPI GM distributor. Did you check timing after installing timing chain? It should have been fairly close to spec. If it was/ or is way off timing chain could be a tooth off. Did you get this car this way (buy a project) or did it gradually get to the point where it needed some maintenance? Verify plugs are routed correctly? Codes? Check ground wires. mods? vacuum leaks? When it's running what are MAP,MAF, and O2 reading? Does it still have cat conv?

s carter

Years ago I had an 87 that was giving just about the same Grief I looked at the cat's and fuel pressure and so, Car was hard starting If you Tried to get over 2000 RPM Engine would miss Horribly.

Turns out it was the coil

Tom454

Had me all excited there.... had a new spare coil.... ran right out there and installed it... no difference.

Tom454

Set the timing today... twice.
Second guessed myself on the TC set install when I installed it (months ago) and ripped it all apart to check it.... yup... was installed 100% on the money. Big waste of time that was.

Plug wires verified correct multiple times.

Can't get any codes... my OBD1 scanner is a POS.
Dash is erratic. Flaky.
Will go over some vac lines before I try the other dizzy. They are definitely rotten. I already replaced a bunch. I don't intend to drive it with the substitute dizzy, just want to find out if it will run without EFI computer interference.
Too bad I can't get Tuner Pro working.

VikingTrad3r

ignition control module.

Tom454

That's the next purchase.
This is silly.
I refuse to buy new tires to get it to run right.
That's where I draw the line.

Cruisinfanatic

unplug MAF and see if it makes a difference

Joe C

quick question - have you adjusted the valves lately?

personally, i'd be looking at that distributor, and FWIW, quit throwing parts at the thing.

xrav22

When you are adjusting timing are you unplugging the advance wire (tan one) because if you don't your engine will shake like crazy above 2000 rpm. I thought I ruined my engine but turned it off unplugged tan advance and reset timing and it was purring like a kitten again.
Good Luck

bjankuski

It will not run without the distributor, the computer senses the engine rotation with the distributor and that is how the spark and fuel are controlled. Wrong distributor and the computer will not know the engine is cranking over.

-Is the firing order correct?
-what size are the replacement injectors?
-Did you reset the valves?

It seems like something basic is missing, check for spark, fuel (too much too little), compression.

Matatk

So you have an 85-88. What year specifically?

Are there any codes/CEL present?

This is one issue that having a scanner (or working laptop/software) comes in handy to monitor sensor values, etc.

I would second the recommendation to unplug the MAF and see how it runs.

Another sensor that affects fuel, etc is the coolant temperature sensor. It is located on the front of the intake. Quick and free to check, ohm the value and compare to the chart in the FSM or you can find the values online.

You also mentioned fuel pressure is good, but what is the actual pressure you read and what is the value under load?

If none of those, I agree it could also be ICM related, but I like to test the free stuff, first.

Let us know how testing goes.

Tom454

It runs great between 1100 ands 1900 rpm. So that's why I'm thinking it might be the tires. ha ha

Since it does run great between 1100 ands 1900 rpm, that rules out firing order, spark etc.

The valves do not have to be readjusted when changing the Timing chain & gears... not since the last time I checked anyways.

Injectors are Accel #150824, 24lbs/hr

It has to be something with the electronics.

p.8A-20-8 FSM has the schematic.

The ICM (passenger side fender well) seems to be simply a knock sensor interface to the ECU... i.e.- it's not connected to the dizzy.

The EST module inside the distributor feeds to and receives from the ECM. I think I have a bad ECM or a bad EST module, or both.

Tom454

No difference. First thing I tried.

Tom454

The connector is tan... the wire is white. Yes.... unplugged it to set timing.

Edit: Brain Fart Alert... the wire is tan as you said. The connector is black.

I was thinking about the TACH wire. Sorry.

Tom454

I drove the car home with the stereo, A/C and the cruise set. Valve lifters are factory rollers and were fine. Car ran smooth on the highway. Just rough to start and keep idling.

Matatk

The ICM (ignition control module) is a solid state electronic located on top of the distributor underneath the cap.

Tom454

Studying the schematic now.

Matatk

No scanner required to check codes, just a paperclip or jumper wire.

http://www.corvetteforum.guru/module...post_id=248955

Matatk

What are the actual fuel pressure values? Key on and running.

Here is another thought:

Did you verify top dead center when everything was apart? I mean mechanically by pulling the #1 spark plug? The reason I ask is because the harmonic balancer on these can separate at the rubber portion and allow the outer timing ring to slip. That will give false values for setting timing. Happened to me personally, that's how I know.