300lsx

i have a stand alone lt1 based motor in my car, recently did a new build on the motor and a problem from the past has revived itself. The car ran great for about 15 minutes and then died. After letting it cool down for a few hours it will do the same thing. Last time it was the opti and I replaced the icm as well. I was using an accel opti and heard this could be the issue. I went ahead and replaced the opti and icm again because they were under warranty and ended up not resolving the issue. Any ideas on why it would keep shutting off after it gets warm?

mcclintock89

Sounds electrical to me for sure. Since you did a rebuild, I would suspect anything and everything that was in the car before and after. Anything show up on an OBD scan? If you've already replaced the opti and the icm, did you by chance replace the coil as well? It could also be that there is a short in any of the wires that control the primary ignition sources. (wire running to opti, icm, or coil)

You could also do a few other tests to see if you are indeed getting a spark when you hit your "engine dead" temperature. Take one of the spark plug wires from the opti and just connect it to a spark plug or multimeter and see if you are still getting a spark.

Just a few thoughts, hopefully it points you in the right direction!