Jimmymike1

Yesterday I was driving 60 mph and the car cut off would not start after 10 minutes. I had it towed to my mechanic. It stated this morning but cut off again after 5 minutes and would not start. He says it is the opti spark but he did not check codes. Looks like the car shuts off after warming up. Any suggestions before I start buying parts.

Thanks much

Jim

93Rubie

If your guy is worth his salt. He will check codes. If he is REALLY worth his salt he will have a scan tool that can see the High Resolution and Low Resolution signals from the Opti-Spark. See if he can monitor those as the engine starts to run bad and quits. Then try to crank, see if you have those or not.

My ENTRY level Professional grade OTC Nemisys scan tool will do this.

Also what are you losing? Spark/fuel, etc...? What?

Just throwing Opti-Spark out there is BS. It can be a lot of things. Shouldn't take more than 1 hour to VERIFY your issue given its doing it often and easily repeatable. A little diag. goes a long way. Hold off on the ol' parts cannon.

Jimmymike1

Thanks for the input. We are checking codes in the morning. No spark after the car has run for 5 minutes and has warmed up. I will give him you input on the opti-spark . I told him NOT to purchase any parts until we have done a full diagnostic. I have fired that parts cannon on a previous restoration, it gets painful.

Thanks for the guidance.

Bandit's C4

Agree with a thorough diagnostic - a common symptom may have an alternate solution.
Been there myself with the 93 last Summer - http://forums.corvetteforum.com/1582073051-post34.html

Jimmymike1

The car threw a code 42. The shop is replacing the ICM module. Any thoughts? i will update this afternoon if repair works.
Thanks

Jimmymike1

The car is fixed. ICM module. Thanks for the input. Great site.

Pingman326

I'm also a 1993 Corvette owner, what is the ICM module and where is it located in case I ever have the same problem.

Thanks,
Steve

Bandit's C4

Common abbreviations -
ICM - Ignition Control Module (front face/right side engine block)
IAC - Idle Air Control
ECM - Engine Control Module (main engine computer)
MAP - Manifold Air Pressure
TPS - Throttle Position Sensor

Jimmymike1

Note..the coil is attached to the module. As noted by by Bandit and 93Rubie having the codes checked was the key to the repair. The mechanic I had(note had) was going to put a new opti spark(distributor) on the car before I stopped him and had him check codes. thanks to this forum.. Car is running great.

Drew

Wow Opti vs. ICM....You just saved yourself a TON of money. That mechanic was looking to Hurt your wallet......You would have had a new Opti but the same issue you had before and that would have sucked...Glad you did the right diagnosis.

93Rubie

Codes give you a place to start with. Glad to hear you got it going.
I suggest you get a FSM for your 93. Worth its weight in gold.
They have diagnostic flow charts for each code and such. Invaluable.

Jimmymike1

I will track a FSM down at once. Thanks

93VettePilot

Make sure the shop used the convective sealant behind the ICM and Bracket. If not it will overheat and you will be buying another ICM in short order.

Jimmymike1

To: 93 VettePilot. The part had the thermal grease which was used when instaling the new ICM. Is that what you are talking about?
Thanks