Started with previous owner carried on to me. Previous owner was BIGSHAFE if you want to look up the threads he posted on it.

Basically I got the car and rebuilt it New rings bearings Oil Pump Stock cam and Lifters.

Something in the ingnition or soemthing when the motor gets warm starts to make it misfire. We had thought it had something to do with having a chewed up cam, well now that thats not it were stumped.

So my question is what is there that could malfunction when its hot that works fine when its cold. Coil, Optical Sensor, Coil Plug wire, Cam sensor, any thing along those lines that anyone can think of.

I,m at my wits end to fix this. If I have to I,ll just do the OTHER opti delete and get a WHOLE new wire harness for the car. I dont want to spend that kind of money but the car just wont run right after youve driven it a while and gotten things nice and warmed up.

Misses, backfires things like that.

 

checked that yet?

 

Ok I,m semi NEW to LT1s I know what PCM is what is ICM??

 

Here is what a Haynes manual says to look for on backfiring....

• EGR system not functioning properly.
• Ignition timing incorrect
• Vacuum Leak
• Damaged valve springs or sticking valve.
• Intake air leak(falls under vacuum leak).

I will do some looking to see what my GM manuals say about it.

 

Ignition control module. It is mounted with the coil(driver's head). From Shoebox's page.....

 

Sounds like the opti. Mine did the same thing. when i replaced it the car feels like new. I opened up the old opti and it was rusted and everything in the back.

 

I just installed the EFI 24X opti delete kit on my car. I would recommend you do that instead of buying a new opti. You can make your own harness to. They sale a kit to do it with for an extra 100 bucks.

 

How many miles are on the opti? It sounds like a bad opti to me. Wierd that its only a problem when its hot though.

 

If you all havent noticed I have LTCC, So I have 8 coils not one. I dont even think I have that module, '

The Opti is used but the only thing that is being used is the optical sensor.

I Like the idea of doing the 24x conversion as that one deletes the opti all together.

 

Man all you need is the 24X kit and a LS1 pcm and all your problems will go away.

 

I know I know, but what is something like that going to run me if I got the coils and I make the harness myself which I really dont want to do??

 

I have since removed the LTCC and reverted back to stock with a NEW rebuilt Opti and everything is great now. Must have been a short somewhere in the LTCC setup or abad COIL or something.

 

You mentioned that you suspected the optical module or the "cam sensor" (which is the optical module). It isn't unheard of for the optical sensor to heat soak and falter under high heat conditions. How did you determine that it wasn't the Opti, and decide to blame it on the LTCC?

 

Well we switched out the Optical sensor with a different one (NOT NEW) and the car wouldnt even run. So we swapped it back to the one that was in it. It ran but still with the miss. So my friend was like, I got a NEW REBUILT OPTI we can try to see what happens. So we did, no go still missfired. So I said &^%^ it, and reverted it back to stock since I had the ICM and the COIL. I had to order the Pigtails for both those and get new wire but it was worth a try.

So either there was something wrong in the LTCC control module or a coil went bad or something. Ive ran it for two days like this with no issues whatsoever.

So what Im thinking is that the problem from the original owner was different from what I was having after the rebuild or something. I dont really know I just know it works.

 

Unless you tried with a NEW (not new rebulit) AC or Delphi unit I would say it was the signal and not the LTCC.