ICM, opti or coil problems
TECH Regular
Joined: Oct 2011
Posts: 407
Likes: 2
From: Keller Tx
I went ahead and toss in a new Coolant Temp sensor. I should have replaced it when I did the opti/water pump last year. I measured the old one it and it was around 2.3K at room temp. Maybe it worked but now I don't worry about it.
So i took the car out today with a pressure gauge. After 20 mins of driving around it started to stumble real bad and actually shut down. There was no change in psi. I pulled over for 5 mins tops restarted the car and drove it home just fine. It threw two codes tho 16, 36. Hi and low res failures. Does this prove the opti is bad, im going to go over the harness one more time. Any other suggestions?
check the harness again for breaks and opens...If all is good then YES your opti IS ****.
also did you check to see if the pump is putting out enough volume?
with the gauge connected it will have a psi relief valve on it. WHile its running open the relief valve it will start to dump out fluid. THe car should run like nothing ever happened. IF IT dies out or stumbles then your pump is bad!!! Just because its putting out the correct psi doesn't mean its the correct volume.
also did you check to see if the pump is putting out enough volume?
with the gauge connected it will have a psi relief valve on it. WHile its running open the relief valve it will start to dump out fluid. THe car should run like nothing ever happened. IF IT dies out or stumbles then your pump is bad!!! Just because its putting out the correct psi doesn't mean its the correct volume.
TECH Apprentice
Joined: May 2009
Posts: 323
Likes: 2
From: NW AR
To be honest and alot of folks on here agree to the comment "if it works dont touch it" when dealing with lt1s. Sometimes aftermarket coils, icms, etc can make it worse as there **** quality. Do the simple voltage tests to find the problem is and stop beating around the bush its very simple and will tell you wtf is actually going on. Maybe im just retarded for trying to help solve your problem cause you dont seem to be listening.
As for the parts I used, I used and MSD coil originally and it died, then new one I got kind of sucked too, and the third one finally worked. Even though they were all the same part number, every one of them was a different design. The ICM that I originally replaced was some knock off that like I said before lasted less than and hour, I replaced with an OEM unit. And the fuel pump was a Walbro 255 that quit working.
I know what your going thru,...here you go,...
https://ls1tech.com/forums/general-m...tarting-solved.
https://ls1tech.com/forums/general-m...tarting-solved.
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If i read everything correctly it almost seems like you had two problems. The switch and the opti. Im just going to swap my opti out this weekend and see what happens, its still under warranty so all ive got to lose is a few hours work. But i feel ya its super annoying not knowing if youre gonna make it home or not
FWIW....when my ICM took a dump recently, it took out my MSD coil too with it. It very well could be your opti however; always a pleasure to deal with
Had to get both new ICM and OEM replacement coil from autozone....works great now.
Had to get both new ICM and OEM replacement coil from autozone....works great now. For me it turned out to be the Opti,...heat soaking the opti module and it dropping out till cool again.
I have a new ignition switch now too. And a good used one if needed.
I have a new ignition switch now too. And a good used one if needed.
If i read everything correctly it almost seems like you had two problems. The switch and the opti. Im just going to swap my opti out this weekend and see what happens, its still under warranty so all ive got to lose is a few hours work. But i feel ya its super annoying not knowing if youre gonna make it home or not
