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Topic: Engine Stalling Issues on '93 Base LT1.

in Forum: C4 Electrical

Engine Stalling Issues on '93 Base LT1.

Posted: 5/8/17 8:58pm Message 1 of 7
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Joined: 6/4/2016
Posts: 16
Vette(s): 1993 Chevrolet Corvette Base Edition. Exterior Color is Polo Green with Tan interior. 5.7 LT-1 V-8 with 4-speed automatic transmission.
I have stalling issues on my 1993 Chevy Corvette 5.7L LT1 w/ auto. It would run for a minute. Then it will shut off all of a sudden. Sometimes, it will fire right back up and stall out again, or it will keep cranking and won't fire up for about 5 minutes or so. I check fuel pump pressure and it was good. It sounds like the common symptoms of a faulty ignition control module. So, I went and bought one from Auto Zone and installed it. It's still stalls out. I checked for spark and there was none when it stalled out. I scanned the ECM for trouble coded. They were 16 & 43. I noticed on the Opti-Spark distributor lead circuit from the ECM, there was a voltage reading of 8.9 volts. It supposed to be a 5 volt reference. I also noticed a low voltage reading of 0.5 volts on the ICM circuit coming from the ECM. Could it actually be a bad ECM that is causing me this grief, or bad ECM ground or bad ECM wires touching each other. I don't want to spend money on a ECM if I don't have to. I want to make sure that I cover all based before I even buy a ECM. If anyone has any suggestion, I would appreciate it. Thanks.


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Re: Engine Stalling Issues on '93 Base LT1.

Posted: 5/19/17 10:55am Message 2 of 7
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beaufort, SC - USA
Joined: 9/1/2009
Posts: 39
Vette(s): 1990 Turquoise Corvette (his) & 1990 Turquoise Corvette (hers)indy festiville car for sale
LOOK AT THE IDLE AIR CONTROL VALVE,IF IT GOES BAD THE WON'T IDLE.


Re: Engine Stalling Issues on '93 Base LT1.

Posted: 5/31/17 8:58am Message 3 of 7
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decatur, AL - USA
Joined: 4/3/2014
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Vette(s): 1st and only Vette so far. 1994 Polo Green Matallic base coupe. Bought in November 2013 with 200,000 miles on odometer. Runs great and almost everything works.
Check the throttle position sensor, that was the problem with mine. 

I have a 94 base coupe, Polo Green with tan interior just like yours. 

When it just cranks without starting, play with the gas pedal moving it a little at a time. That might hit a spot where it catches the signal and starts right up. 

On mine, the first time it happened I pumped the gas over and over til it started. I figured if I could hit the mark on the TPS, I could get it going.

Hope that helps.



Re: Engine Stalling Issues on '93 Base LT1.

Posted: 5/31/17 9:10am Message 4 of 7
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Former Member
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Joined: 6/4/2016
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Vette(s): 1993 Chevrolet Corvette Base Edition. Exterior Color is Polo Green with Tan interior. 5.7 LT-1 V-8 with 4-speed automatic transmission.
Thank you.


Re: Engine Stalling Issues on '93 Base LT1.

Posted: 6/1/17 11:18am Message 5 of 7
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El Paso, TX - USA
Joined: 7/22/2015
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Vette(s): 1963 1987 1994
You hit the nail on the head when you said you lost spark.  Had the same problem with my 94.  Mine turned out to be the ignition module but you have already replaced that.  Look for things that affect timing.  Cam position sensor, crank position sensor, etc.  It could be the ECM, but that's an expensive diagnostic tool.


Re: Engine Stalling Issues on '93 Base LT1.

Posted: 6/6/17 9:14am Message 6 of 7
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I have a 1991 L98. I had the same problem. Ended up being the EGR ELEC VACUME VALVE. And ECM.


Re: Engine Stalling Issues on '93 Base LT1.

Posted: 6/6/17 4:41pm Message 7 of 7
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Former Member
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Joined: 6/4/2016
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Vette(s): 1993 Chevrolet Corvette Base Edition. Exterior Color is Polo Green with Tan interior. 5.7 LT-1 V-8 with 4-speed automatic transmission.

First of all, I want to thank everyone who replied back to my post. I want to say that I ended up taking my Vette to a shop out past Murrysville, PA. that one of my friends from the United Rays Corvette Club has recommended. They found the problem. It was a bad optical sensor in the Opti-Spark distributor. For what I’ve been hearing, this is a common problem on the LT1 V-8s from 1992-1994. When moisture and dirt get inside the actual distributor assembly, it creates various symptoms such as stalling, erratic idle, and miscellaneous engine malfunction codes (GM OBD1 as well as OBD2). It’s a big bill, but hopefully it’s worth it. I figured that I would share this information with you guys if you have a 1992-1996 C4 Vette with a LT1 350 V8. I don’t believe in keeping any information on the solution. Hopefully, I’ve helped someone who is having the same problem. Once again, thanks.




in Forum: C4 Electrical


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