Working on mystery issue truck.

[LSVolvo940]

Tried to stick a computer back in the truck that was not changed but reflashed cranks but no start. The truck is a 2003 z71 Silverado with a 5.3. Currently ripping the O?S with lsDroid. The truck would run with the computer that came in it when I bought it but runs richer than a can of corn and gets like half a mile per gallon. OS # READS 12579405, checked my recent bins and that os is 03 2500 6.0 lq4 2wd in the bin/xdf that i have for that OS. The question is though how did it even start before with that computer and cranks but no start with this other one,. Maybe i made a brick out of the p59 12597120 that I flashed here. My Volvo runs like a champ though throws a couple trans, an air and a fuel tank pessure code, might try that ecu in the truck but the flash is with a 4l80e so better leave that alone.

[Neukam]

Just guessing here, but could it be a security issue? Perhaps you need to do a security relearn if you didn't disable VATS. Also check to make sure that no pins backed out when you reinstalled it. Do you have any communication with the PCM? Any codes?

[LSVolvo940]

The truck runs now, I could not find an XDF file that matched my 03 file OS so I found a matching set and rewrote the OS and bin to some 04 files. It started up rough at first, no odometer or lights on stereo so I fooled around with it a little bit . Drove it around the Block for a minute, definitely seems more responsive than before and downshifts hard "doesn't Bog down like it did under heavy throttle". Flipped the headlight switch a couple times then the lights all worked, seemed dim, never did before I switched ECM though. I bought this truck with a blown trans, they completely raked the low planetary clear out of it. When I did the Trans I gutted the cats. I know it needs a little tuning but at least this bin runs, still have all of the stock sensors fully intact . Runs drives and no check engine lights besides abs. I have never seen a truck that ran this rich before in my life. It still puked out a bunch of black soot when I revved it up a little higher. May just need to take time to clear out. Way better than it was before.

[LSVolvo940]

Just guessing here, but could it be a security issue? Perhaps you need to do a security relearn if you didn't disable VATS. Also check to make sure that no pins backed out when you reinstalled it. Do you have any communication with the PCM? Any codes?

Completely neglected to delete vats when I re-flashed . This is all still in a stock original vehicle . It worked for me this time anyways.