Hello. So as many of you know I have been dealing with a broken corvette for a year and a half now. I've dumped a ton of money in a brand new engine and a lot of diagnostic problem eliminating work.

The engine is supposedly A ok
The electrician I hired has gone through every single wire we've replaced everything even the computer. yet the gremlin still lives.

We have done EVERYTHING except for 2 more things.

The ignition control module or the distributor.

He basically said if this isn't it, he's hit a brick wall and there is nothing else he can do.

My symptoms are this. The car runs GREAT when it is cold. It runs good for about 5 min and then degrades until about 20 min when it just completely goes to hell. It is not firing the injectors correctly and I am getting jerked forward with power and then it bogs down throughout the RPM range. By 20 min the car is only running on 4 cylinders. The electrician said the computer is shutting down the passenger side fuel bank. But remember this only happens when the engine gets hot.

Now through my research I've discovered the ICM usually shows itself when the car is hot, however most times it shows itself by not allowing the car to start or it shuts it down. So its an on or off type thing.

The distributor I would feel shouldn't be affected by temperature?
However I heard current is affected by heat so i really don't know.

What do you guys think? This problem is electrical.

 

The electric control module is only a few bucks. Why hasn't he replaced this earlier given your symptoms?

 

Because he said it is an on off type thing. It either works or doesn't. It wouldn't half way work ect..

Is it the ignition control module or Electric control module??

 

At least your will start and run for a few minutes, the one I am working on does not have power to the ECM. The iginition module in the distributor you can get it check at your local autozone for functionality. At least you can narrow that one down.

 

what year?

 

1989

 

L98 unless the injectors are shutting down on that one side it doesn't make sense. Is fuel pressure ok after the 20 min ? Have you checked the fuel filter, it could be filled with crap and takes some time to clog under pressure. Take the pressure off and the sediment unclogs itself. The module in the distributor could be getting hot, those are cheap and easy to do.

 

Pick up coil in distributor failure would car engine to stall may or may not restart until it cools. Ignition module normally will cause a loss of spark vs injector pulse. I'm not sure it would turn off half the injectors. It seems a DTC would set 41,42,43,44, or 45... MAF can also cause similar conditions many times maf relay(s) will fail. Are you using scanner to monitor data? I mistakely thought this was a 89 from previous treads Is this your modded 94 LT1?

 

I would connect a fuel pressure gauge and monitor pressure the whole time it's running.. tape it to the windshield!

 

it is a 1994

 

yes that is right it is a 1994

 

The fuel pressure was tested at the engine rebuild shop, or so they say. The fuel gauge I have on the car is reading 5 psi but that is impossible right? the car wouldn't even run at 5psi. I think the gauge is just broken and i can't afford to buy a new one, i've run out of money lol. But if there was a problem with the pressure i don't think the car would run while its cold and not hot. I will check the fuel filter ASAP but again

at 5 psi... the car can't run can it?

 

From reading August thread, did you ever get a custom calibration. If engine was built and installed with all those mods it won't run right with stock ecm, and what you describe could happen when the computer took control over the preprogrammed start up functions. 5lb fuel pressure car shouldn't run but with the oversized injectors it could. I don't think a stock fuel pump would be able to supply the volume of fuel to allow injectors to spray properly.

 

tested the fuel pressure and it is ok

Kevova remember I ran these injectors on a stock ecm for 4 years with no problems.

There is a disruption in the circuit that controls firing the injectors.

Seeing that the distributor sends the signal to the computer and the computers send the signal to the injectors, a bad coil pack could be messing with the computer and the computer shutting off the injectors.

 

94 has sfi - injectors turn on one at a time vs tpi or mpfi - 4 injectors at a time on each branch. to lose 4 injectors with sfi the 12v supply circuit is suspect, there are 2 fused circuits ecm applies ground to each injector . You have a few different threads relating to mods and how your car runs it gets confusing.

 

So you are reading 5psi but you are not sure. You want to fix the car but not willing to pay for a 30 gauge to see what your fuel pressure really is. At this point not being smart I would just stop till you can afford what you need to try to get it strighen out

 

Read.

I just told you two posts up I had the pressure checked and it came out ok.

 

Check the plug on your Opti and make sure all 4 wires make a good clean connection. There is, Low reference, Ignition feed, and a High & Low resolution signals. If the low res signals don't make a good connection, the spark crank position gets lost along with the correct injector reference. It won't find it's orientation until the crank position mark comes around on the next revolution. The car will load up, struggle and quit. Heat will change the resistance across a corroded connector and raise hell with trying to trace the problem. A bad or cloudy sensor inside a failing Opti will do this too and mine didn't ever throw a code except "misfires detected" until it finally failed completely.

 

How did he determine this? Did he use a Noid light test?