Basics: 94 Trans Am 6.0 LS swap
L92 heads, LS3 intake, fairly big cam, long tubes...
I can't get this thing to run consistently. One day it works great, idles, all that. Don't even TOUCH it, the next day it won't fucking run right. Basically the left bank (Bank 1) is not firing. I've verified injector pulse at all injectors. I've change coils from another motor I have laying around. Power at the coils. I traced all the wires back to the computer, those are good and in the right position. I've checked everything I could think of. Problem is I can't check spark when it's running bad since my timing light took a shit. The times I've checked, I have spark during crank. But here's the deal...
Sometimes when it starts I can see O2 signals, then you can hear the engine change pitch and see the Bank 1 O2 drop to lean. I'm assuming that I'm losing spark, with no help here (just myself) and no timing light I have no way to verify loss of spark during these conditions. What I do know is the left bank is fouled out with fuel (need to change plugs again) and the right side is fine. Also, during this time the left bank header primaries are dead cold and the other side is 150-200 depending on how long it runs.
After an hour or so I gave it another go. This time I had help to crank while I did a few tests. It fired right up and idled for a few seconds then started running like shit again. Bank 2 wasnt firing this time and bank 1 was (opposite of before). By not firing, I mean no spark... Do I have a bad PCM? WTF would cause it to jump banks, still throwing no codes.
Attached are log files, config, and tune. Log files are dated. 6-22 was when it was running good, a bit rich but idled very well. 6-26 is today obviously, 2 separate "runs". I didn't get a chance to log the other run that I did last (when it switched banks).
ANY IDEAS???? Bad PCM? I'm at a loss. NO DTC's thrown.
Please help before I push it off a cliff.
Anything you think I'm missing, please let me know.
Thanks everyone,
Jeremy
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