Firewalker11

Hi guys, I have a problem with my 1994 Coupe and I am hoping you can help me out. I took the old girl out today because it was mild in Ohio for a late November day. Everything was great until as I was driving around 50 m.p.h. and the engine simply shut off. The tachometer went to zero, and I coasted to the side of the road. I opened the hood, nothing amiss. I tried to start it and while the car tried to turn over, you could tell there was no spark whatsoever. Called AAA for a tow and waited. About 15 minutes later, still waiting for the tow, I tried to start it again and it fired right up. I tried to drive home and about 2 miles down the road the same thing happened, loss of power, coasted to the curb. I had it towed to the shop and here I am.

Any thoughts? Opti-spark? ECM? The car is a 1994 with 99k miles, 6 spd. Any ideas would be greatly appreciated.

Thanks in advance
Jeff

1993C4LT1

If you want, I can tell you how to test the opti. If opti is good, I think coil or ICM.

Firewalker11

That would be great. How do you test the opti?

1993C4LT1

Get the engine to shut off on you again. If you don't have the the LT1 noid light, get it. When it shuts off, pull off the driver side fuel rail cover, unplug the fuel injector connector. Plug the noid light in. Try and start the engine, keep an eye on the noid light. If it doesn't light up while cranking, opti is bad.

DanielRicany

My money's on the opti

lt4obsesses

Classic ICM issue.

1993C4LT1

Also a classic opti issue. I had the same experience as OP. Replaced ICM, damn thing turned off on me still

Firewalker11

I am leaning on the Opti but as others have said, ECM or ICM? I do appreciate everyone's input. The garage is to call me today and I expect them to say that the opti is bad. The garage does provide a 2 year warranty on parts and labor so that is good but I am expecting at least a $1000 repair...ouch.

Thanks again for the advice, I will update as the situation evolves so that others may benefit from my experience.

Jeff

seijack

At a shop the cost may be more like 1500-2000, maybe...When I did mine I did it myself and I had $800.00 in parts. But I did use an MSD opti, new waterpump and all new hoses. Let us know what the estimate is...

MRPVette

I replaced mine myself for for $525 with a new water pump and a Delphi opti not near as hard to replace as thought it would be can be done in a day no problem.

Firewalker11

I think I will try to replace the opti and water pump myself. The repair shop quoted $1930 to replace the opti and waterpump with ac delco components, $1400 with non AC Delco parts.

I simply cannot afford that right now. I may just bring her home, park her in the garage and replace the opti and water pump this spring.

Thanks again for all of the input!

Jeff

c92vette

I replaced the optispark distributor 2 years ago with one from eBay. Ran about $80 with shipping from a reputable seller. Mine went bad due to worn out bearings that seized up and cooked the rotor. I've got about 500 miles on the replacement part with no issues. It took me about 4 hours on a weekend to replace it. I got a lot of info on "how to's" from the members of the forum. Depending on how much of a chance you wish to take this might be an option you want to look into. Best of luck.

seijack

Firewalker11,

We don't have much more driving weather here in Ohio anyway, do a few searchs here on the Forum there are quite a few write ups with great pics. Definitely go with delco water pump, the opti is your choice, I chose an msd opti, but there are other options just make sure you go with a vented design. Jan or Feb is a good time to do this, there is nothing to do here then anyway. Its not a hard job it takes a litte time. It would be a good time to give the engine a good spray down and scrubbing as you do not want to do it after you put on the new opti. It would also be a good time to change the plug wires too.

lt4obsesses

You know the ICM,(ignition control module) is located on the passenger side head, just above the coil. It is mounted to the bracket by two 7mm bolts. It's removal time is all of about 5 minutes. It can be tested at you local auto parts store. I would at least have it checked before chucking what might be a perfectly good opti-spark.

Yes, opti's do go bad, but it seems that every time one of these cars has the slightest hiccup, that's the first thing people replace. Given the current hit or miss status of after-market opti's, i would work very hard to rule out everything else before just going off on whim and replacing a high quality part with a cheap aftermarket clone. Just me.

1993C4LT1

That's why I told the OP to see if opti is good or bad. Like you say, hit and miss. I didn't say replace your opti, I said test it first. No need to throw parts.

Firewalker11

The more I research it, the more I think the ICM may be bad. I took your advice, removed the ICM and took it to the auto parts store. The ICM passed the test but obviously the ICM didn't get hot during the test and THAT is when I experience the failure. I can get an AC Delco ICM for $70 so that is where I will start. That is a lot cheaper and easier than pulling off the opti. I will update once I receive and install the new ICM. Thank you so much for the information, I really appreciate it.

Jeff

HlhnEast

Jeff, you are right about getting the ICM hot. Most auto parts should know that. Take it back and make them run it about 3 times and that will get it hot enough to show an issue if it is the problem. Tell the folks to be careful because it will be damn hot, lol.

Good luck!

Firewalker11

UPDATE****

Since I hate it when people post their problems, and get a bunch of advice but never come back to share what they learned during the process, I am updating my post!

My 1994 coupe died while I was at cruising speed. It was if someone had flipped a switch causing me to coast to the side of the road. 20 minutes later it would start just fine only to stall again a few miles down the road.

On the advice from a fellow forum member (THANK YOU) I replaced the coil and the ICM. I used AC Delco parts and total cost was under $130. I did this even though the garage that I took it to said it was the opti and quoted me almost $2,000 in repairs. I figured I had nothing to lose by replacing the ICM and coil since they were inexpensive AND 20 years old.

Today she started up fine and ran down the road like new again! Moreover, the dash has never looked so bright, which I thought was kind of weird but anyway, so far, so good. I did let it idle for 15 minutes and drove around the neighborhood. I was too afraid to take it out too far in case it stalled again. Tentatively, I am calling this a success and will keep my fingers crossed that it holds.

Thanks much to all those that offered help and suggestions, you guys rock!

Jeff

MaxDaemon

I hate that too! Thanks so much for updating - and congrats! It's sure great that option number two was only a tiny percentage of the cost of the alternate!

Firewalker11

Since I thought I had my car fixed I took it out the other day for a winter drive. It drove great for the first 20 minutes. Once again, while driving at highway speeds, the car simply shut off, leaving me to coast to the side of the road and call for a tow. At this point I am going to have the opti, water pump and all heater/radiator hoses replaced. I have purchased the opti from SacCityCorvette and hope to get it installed soon.

I was hoping that replacing the coil and ICM would fix the problem but the hunt continues. I will update once completed so that anyone who experiences the same problem can find a cure.