AVID

Good morning all,

At the end of last month after a long day of driving around the state, when I went to start the car and go home it fired up and about two seconds later just instantly died. trying to start the car again the engine would spin for days but not actually fire up. After trying a handful of times and waiting around 5 minutes it started up and I started moving down the road. After going maybe a 1/4 mile down the road it died again and refused to start up. after trying a couple of times it started up again and I was able to go down the road and stop at a gas station. I filled it up since I was at about 1/4 tank and thought maybe my sending unit was lying to me and I was closer to empty.

The car started up after getting refueled and I left and started out on the highway and headed home. I made it about 40 miles from the gas station when the car died as I was rolling at about 70 down the road, pulled over tried to restart it and eventually started rolling down the road again. Repeat this process about 25 times until I made it to about 30 miles away from home and got a flatbed the rest of the way home.

Now, naturally when the flatbed came the car started right up just fine and was able to get into position no problem. The same thing happened when we made it back to get off of the flatbed. The car wasn't running rough, it would just die like hitting a kill switch and then just refuse to start for a minute or two everytime it happened. I had power to everything when it died, the engine would just stop.

This leads me to believe I'm probably looking at an ICM problem considering these problems happened after a long day of driving around and the engine being at operating temperature for a few hours, coupled with it being about 90 that day. The shop that I took it to doesn't have much experience with the LT1 so they didn't want to do much to it. The pulled I believe a code 41 which, if my memory serves me correctly, is Ignition Control Circuit Open. Which, points to the ICM. The shop believes the problem is the Opti given the advice they were given from someone with "more experience with that engine". I'm not buying it. I just replaced the damn optispark a little over a year and a half and 6,000 miles ago.

I'm going to pull the codes myself to see if there's anything else besides that code 41 (unless of course they did the courtesy of clearing the codes for me...) because if there's not a code 16 or 32 as well as the 41 I'm not inclined to believe it's the optispark, especially since the car was not running rough or misfiring. It was only dying like someone hit a kill switch.

Thoughts on this? Am I right to rule out the Optispark in this case or should I look at that as a possibility as well?


TL;DR Car continuously died while hot, didn't run rough, and set a code 41.

Kevova

ICM is not a bad guess, but with not diagnosis that's all it is. The 41 sets on start up or crank. If you choose to drive around with as I call it a "stall kit" consisting of: noid light, fuel pressure gauge, test light and spark tester. When it quits again you can see what your losing. Then evaluate what you need to do.

SJW

Far too many poorly trained technicians who can't troubleshoot their way out of a paper bag are all too quick to pin any and all problems that arise with the LTx engines on the Opti.

Nothing you describe points toward the Opti, other than the fact that a failing Opti can cause an engine to stall. So can dozens of other things. Stay away from that shop.

If you don't have the diagnostic tools and skill to DIY troubleshoot and repair this fault, enlist the help of somebody who does. Don't go down the rat-hole of throwing expensive parts at it.

Good luck with it.

Live well,

SJW

AVID

I'm going to attempt to do this once I get some free time. Thanks for the suggestion.

AVID

Thanks for the input, I'm going to try some troubleshooting that I know I can do and enlist some help for the actions that are out of my scope. I'm willing to lay blame at the ICM at this point, and will see if that pans out to be true after I go through the diagnostic procedures.

scrappy76

Every Icm I have had go bad or others I have known to go bad, They go dead, no restarts that I have ever seen. Now I have heard new ones getting hot and going out because of not being installed correctly but yours is not new. You say you would go 40 miles or 4 miles and it would die is to me odd for an Icm, but I could be wrong.

94corvetteC4

I had a similar issue yesterday. I started my car after work but with a cold engine. It ran for about 30 seconds then instantly died. I tried to restart it about four times right after it stalled but all it would do is crank and not even try to start. I went home then returned four hours later to see if I could figure it out. I decided I would see if it would start before I did anything else and it started and ran fine. I let it run for a few minutes then I shut it down.

I'm going back tonight with a friend who is a mechanic and he is bringing diagnostic equipment and a dolly incase it shuts down on the 5.5 mile ride home.

Richard Raichert

That is exactly how mine acted! Opti Spark.

AVID

Well, as an update: I got some time to do some diagnosing today and I started by checking for codes. I used the method of shorting pins 4 and 12 to get the CCM to spit them out. One single code, on module 4. H16. I just had the optispark replaced a year and a half ago, barely 5,000 miles thanks to northern winters. Is this really what the future is gonna hold? Optis that last barely 5,000 miles and need replaced every other year like it's just regular maintenance?


I just don't get it, car hadn't ran rough or struggled at all. It just died. The best part is I will go out there and start it up right now and it will start no with no problems and idle just fine.

I love this car, but it really doesn't seem to love me.

Richard Raichert

When mine acted that way, when it did run perfect I was always looking for a place to pull off if and when it would die! Not much fun in that.

94corvetteC4

I did the same jumping 4 and 12 on the ALDL. 4.1 had a H16 code. That was the only code.

I drove my car home from work the day after it shut down on me. I got 4 miles and it died going down the hwy. I pulled over and it started first try. I drove the remaining 1.5 miles with no issues.

AVID

the light is starting to fade at the end of the tunnel here. Are there no better options? I've researched this to death to try to find a good quality replacement optispark and apparently it just doesn't exist anymore. NOS Delco? Yeah right, those have dried up by now, and there is not a single solid replacement unit that I can find that isn't a roll of the dice.

This is insanity that a good unit is not in the marketplace, there definitely is a market for them. These cars will eventually be rolling bricks soon. I'm starting to feel like I've got no choice but to sell this car because I don't want to have to replace an Opti every year like it's regular damn maintenance. It was never intended to be that way, and I don't want being stranded on the side of the road one thousand miles away from home to be the thing that tells me "guess it's time to replace the optispark"

Dougs63

On a trip 2 years ago, it was August and really hot. I was driving my '94 down the interstate and it would run fine, then out of nowhere, the engine would "stumble" and die. I had to roll over to the shoulder, let the engine cool for 5 minutes.

After 5 minutes, the car would start up, and go for about another 10 miles down the road and then repeat the engine stumble and die.

I went about 80 miles this way until I go the car to the local Chevy dealer. There were no codes thrown and they couldn't get it to repeat the engine stumble in their shop.

So, we surmised that the heat had burned up the ICM (its attached with thermal paste) and they replaced both the coil and the ICM.

After that, the car ran fine and we drove it the remaining 200 miles home with no incident.

Not a fan of blindly replacing parts - on the other hand, the ICM is a pretty easy job and not too expensive to swap out. Might be worth a try before going down the OPTI path.

AVID

Bumping this thread up for a small update. Pulled the car out of the garage since it had been sitting for about 6 months at this point. drove around town all day yesterday and today. On the way home today it died on me again. After I got it started up and back home I pulled the codes as they had been cleared from memory. H16 on module 4 again. Looks like it's the optispark.

I'm looking into the new 24x option from torqhead, they just completed the kit for the corvette and this looks like the route that I'm gonna go. Anyone here have any experience going the 24x route? I'm gonna get this either way and will post an update after I get it installed and get the car rolling with it.

I'm done with optisparks.

TorchTarga94

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FAUEE

You had the same symptoms as me. My ICM was bad. They're easy to swap & test, not a bad idea to have a spare one to be honest.

94corvetteC4

I had those symptoms and it was my opti. Installed a Petris opti back in November and so far so good. I opted for the 5 year warranty since mine is a daily driver and I put a lot of miles on it. I expect it will fail again within the five year warranty period. If it does I will get the warranty replacement and sell the car. Changing the opti isn't that difficult and I'm no mechanic.