sbscott

I became a thrilled owner of a 1989 6-speed that was babied for years by a close friend in Texas. Bought it, drove it to Colorado and, a week later had an engine fire (leaking fuel pressure valve). Six weeks later with six new injectors, new distributor, new engine wiring harness, throttle/cruise cables, etc, I am back on the road...kinda.
I have an thermal ignition failure that occurs after it has been brought up to temperature driving 10 miles or idling for twenty minutes. Once I turn int off and wait for about ten minutes, it will turn over, but won't start, no spark. After five or six hours, starts and runs fine.

Any thoughts for a sad Vette owner

FASTAZU

How was the fire put out? Sounds like another component was damaged by heat of what ever was used to put out the fire.

don hall

Replace ignition control module... easy fix (if that is the problem).

Check other sources and prices.... posted for photo only:

http://www.ecklerscorvette.com/engin...trol-unit.html

sbscott

Water. The was localized to the back of the engine. I was able to put it out quickly. The whole distributor and coil were replaced with new plug wiring as well.

mmandley

I vote ICM as well. They get super hot when running and when mine gave out it would run for 20 minutes, then crank no start. After it sits all afternoon or all night fires right up like nothing wrong.

Its only 125, get it, install it, then let the car idle for 30 minutes. Bet she runs fine then.

sbscott

Thanks guys! Just ordered one. How, to figure out where it sits in the engine compartment!

JimGnitecki

The location of it was shown in photographs on this forum recently for another forum member. Just use the search feature with "ICM" or "ignition control module" as the search key. I'm sure it was within the past few days.

Jim G

sbscott

Ok, I am a bit confused. You have talked about the ICM (ignition control module). Is this the same thing as the ECM or electronic control module located inside the distributor? And then there is the ESC or electronic spark control...

JimGnitecki

You are going to need to learn a bit more about your car to understand what the more experienced forum owners are talking about here.

The ICM is NOT any of the things you mentioned.

The ECM is the computer for the entire car. It is located just under the hood, driver side, just in from of the windshield, above the battery.

There is NO regular "distributor" in the conventional sense like on a traditional Chevy small block. The Optisaprk replaces it. The timing of sparks to each cylinder is controlled by the "Optispark", which is unique to the Chevrolet LT1 and LT4 engines used from 1992 to 1996. It is NOT located above the engine. It is at the front of the engine, under the water pump (read elsewhere on the forum why this is a bad location for any ignition system ).

The ICM is a small electronic "black box" part located at the front of one of the cylinder banks (passenger side I think). I think maybe this u-tube video shows you where, and how to replace it:


This article, although written to sell an aftermarket market, describes how the LT1 ignition system, including Optispark, ECM, coil, and ICM work to create the sparks needed by the engine:

http://www.delteq.com/products_opti.htm


I don't criticize you for not knowing how the ignition system on an LT1 works (I don't know more than the most basic basics either), but if you are going to ask help here, you are going to have to learn at least some of the basics about your car. That means being willing to search on this forum AND do some googling.

Jim G

sbscott

Fair enough. I will do the research and I appreciate the feedback. Yep, I am new and a bit overwhelmed at this point. Time will help!

Thanks again.

smooth1990

The OP's car is a 1989.











No optispark there.

JimGnitecki

Sorry, I didn't look at his profile.

Jim G

smooth1990

I became a thrilled owner of a 1989 6-speed that was babied for years by a close friend in Texas. Bought it, drove it to Colorado and, a week later had an engine fire (leaking fuel pressure valve). Six weeks later with six new injectors, new distributor,*new*engine*wiring harness, throttle/cruise cables, etc, I am back on the road...kinda.
I have an thermal ignition failure that occurs after it has been brought up to temperature driving 10 miles or idling for twenty minutes. Once I turn int off and wait for about ten minutes, it will turn over, but won't start, no spark. After five or six hours, starts and runs fine.*

Any thoughts for a sad Vette owner

Don't have to. Its in the opening post on this thread..

JimGnitecki

Boy, I really wasn't paying attention. Sorry.

Jim G

383vett

Back to the subject, the ignition control module is in the distributor. Remove the cap and the rotor. The module has two wires on the right side and 4 or 5 on the left. Remove the connectors. I belive 1/4" headed screws hold the module in place. Replace this unit. Sometimes when they go out, they symptoms are what you describe.

Just BOB

Original post said "New distributor". If it is new as in purchased from a retail firm, I'd return it under warranty.

sbscott

Roger. That is my plan.

Thanks again. My journey is just beginning!