Ok,
I have installed a new opti spark, ICM, coil, wires and plugs. Car will run for about 10 minutes then die. Will not start up again for several hours. Sometimes, it wont start until the next day. It is a 1995 C4 LT1.
It's my first Corvette and I've always wanted one. Now, I feel it may just be my last one.

 

Have you checked the PCM for fault codes? Link here shows how to do that.http://www.digitalcorvettes.com/foru...56&postcount=9
Are you certain it is losing spark and not fuel pressure? Do you have a Factory Service Manual to troubleshoot any codes you may find?

 

Thanks for the link. I'll give it a try.

 

Steven Ox,

Sounds like the ol' vapor lock problem cars in the 70's had with carbs when the fuel line ran too close to a heat source.

So after checking for codes, if none, after the engine shuts down, consider checking for fuel pressure in the fuel rail (turn off key, pack with rags, and then depress the fuel pressure schrader valve (or first attach a fuel pressure gauge if you have one).

if none, or low, check the fuel pressure regulator and/or fuel pump.

Hint, if smelling fuel (exhaust or worse in the intake), could be a bad pressure regulator --- which when the diaphram fails, can allow fuel to enter the vacume line -- so pull its vacume line and check for fuel.

Might also be related to the O2 sensors -- 10 minutes might be roughly when the engine might try to enter 'closed loop' operation (uses O2 sensors to judge fuel quantity).

If you have the FSM (factory service manual), use its diagnostics section to troubleshoot the O2s.

 

http://www.mainstreamtopics.com/foru...rt-diagnostic/

 

Did you put enough thermal grease under the ICM?

 

Ok,
I put the entire amount of grease that came with the ICM on it, I also have good fuel pressure. I'm not getting any codes on the ECM and still have no spark at all. Thank you all very much for your help but, I am just going to get rid of the car (scrap or fire), never buy another Chevy/Corvette. This was my dream car and it turned into a nightmare quickly! I'm going back to Mustangs.... at least they start.

 

So are you troubleshooting the no spark condition? That really shouldn't be too hard to pin down if you follow the tree in the FSM.

 

And throwing parts at a car whether it is from GM or Ford simply doesn't work. Particularly if you end up replacing only the good parts.

 

In lieu of a FSM , the link I posted above has very good diagnostics for a no spark condition on a LT1

 

Use the link vetteoz posted and also get a Factory Service Manual (FSM). Throwing parts at a problem usually doesn't fix it and it also gets expensive quickly.

You have posted no other info other than it is a 1995. Things like how many miles; the condition it was in when you bought; what problems it had when you bought it; what other repairs and/or changes you made to it; and what the original problem(s), if any, that caused you to start throwing parts at it.

In addition, what brand opti did you install - some are half dead out of the box.

And ICMs from some of the aftermarket companies are crap and do not work very well or for very long.

Now you have replaced the ICM, opti and coil at the same time without a resolution so none, one, two or all three could be causing problems. It could also very easily be something other than the parts you changed.

But the only way to figure it out is to diagnose properly it using the link kindly provided by vetteoz and using an FSM. Not to be mean but if you or someone you know can't do that then get rid of it to someone who can. In the right hands these are fun, great and usually reliable cars. In the wrong hands, they are unreliable, aggravating, money pits.

In either case, good luck.

 

Well, guess they're not for everyone. It's probably something pretty simple, coil, coolant temp sensor, maf connection. Perhaps install issue with the opti, coil, wires. Maybe it is the fuel regulator. Never really said if the engine stops abruptly, or misses and sputters before dying.

Anyways, nothing wrong with Mustangs, it's what you know and what you're comfortable with. You'll find a buyer for the Vette, if it runs well for 10 min. it's a simple fix from running well period.

 

Bye!

 

Given his apparent determination, I would suggest perhaps something with a warranty.

 

=

Good luck selling or trading it as is.

 

Hey Steve hang in there. Don't throw the towel in just yet.My 92 LT1 doing almost the same thing. Going to a specialist over the weekend to figure it out. I'll post up the results. Maybe it will help your situation.

 

I can see it now.

Buyer shows up with a new ICM, FPR, with him. Or perhaps in the walkaround sees a loose connection or something. Buys the car for dirt cheap from our frustrated brother, signs the title. Goes out, hooks up the loose connection or whatever in about five minutes and drives off in the car like a bat outta he$$.

 

Why would you give up so easily when we have so many people with knowledge of these cars willing to help you out. If you decide to dump the car sell it here to a member so they can fix and appreciate the car ! Good luck

 

(0) Troubleshooting = (10) frustration..

 

I wonder what he will do if his Mustang doesn't run one day.