1993 Z28, Engine quits while idiling or driving. After getting towed home car will start. Codes are 16 and 41. I did not have diagnostic equiptment when I had the problem. Fuel pressure @ 43. Replaced coil because of age only. Opti 1 year old, Rock Auto supplied. Car will start now but am concerned about taking it anyware. Any suggestions? Thanks in advance with any suggestions .

 

Next time it shuts down, immediately check for spark.

Have the ICM (DTC 41) tested by an auto parts shop. Make sure they get is good and hot while testing. If it fails:

4th Gen LT1 F-body Tech Articles

What brand is the Opti (DTC 16)? Just about everything on the market now is cheap, unreliable Chinese crap. Even the MSD is not reliable. Only source that seems to be decent is....:

https://petrisenterprises.com/

....and they are often backordered due to high demand.

Shoebox has a procedure to test the circuit feeding the ICM, and Opt:

4th Gen LT1 F-body Tech Articles

 

Thanks for this information. Opti is a Cardone unit. Coil is a A C Delco. Sealed opti with R T V sealant before installation. Added the vaccume kit for ventilation of the distributer.

Three times recently the no start condition has happened. The first time it was 8 degrees F with windy conditions. Second and 3rd times car had driven normally parked for 45 minutes then tried to re start. Temp was around 60 F both times.

Eventually the engine restarted after letting it set for 15 minutes or more. I have Noid lights and a spark checker to bring with me (not driving far drive from home). Have AAA membership with 100 mile towing, if needed!

I have the original non working GM opti for this car.

Thanks again for your reply!
Ted

 

start, engine warms up then dies and won't restart until it cools is often failing ICM. Use heat sink paste on the back side of ICM before install. Most auto part stores have it for $1 in a single use pack

 

Funny enough, both Autozone and O'Reilly doesn't carry the thermal paste separate where I'm at. It comes with the new junk ICMs they have though.

 

Thanks for the suggestions! I think I will try the washer-spacer trick to keep the I C M away from the head for additional cooling.

This I C M is the original for the car.
Thanks, Ted

 

Update , The ICM was the cause problem!

Thanks for the help.