Sorry, long post but I've made several changes that might affect my problem.
Some time along the last couple of weeks, while wrapping up loose ends and tuning, I seem to have gotten the car so it doesn't want to start cold and idles roughly when in open loop. Once it warms up it starts and idles fine.
Recently I did replace the fuse box with one from a non-turbo car and had to swap one of the power circuits for the cam solenoids and turbo controls to a unused automatic transmission control module power pin, both ignition power circuits. This seemed to work fine for the first few days and I didn't notice any problems.
The first time I noticed the problem was 2 weeks ago and the car actually started and ran for about a 1/4 mile, cut off and wouldn't restart. I was trying out my obd2 speedometer for the first time so I unplugged it and after a couple of cranks it fired up and ran fine the rest of the day with me working on the MAF tuning. I did plug the obd2 speedo back in for a few minutes at the end of the day and everything worked.
Labor day weekend, it took a couple of cranking cycles to start and ran rough while cold idling. I thought maybe a tune tweak had loaded bad so I backed up a couple of iterations but it didn't seem to help the idle. I had lowered the idle quite a bit from the original non stock tune, so I bumped it back up some. Of course after playing with it a few minutes it had warmed up anyway and ran fine.
This past weekend it refused to start with the obd2 speedo plugged in, cranked over fine but wouldn't fire off. Disconnected the speedo , no change. Nothing looks funny when I plug in HP Tuners, and no DTC have popped during all this time except once a general misfire when it was barely running on idle. After a few basic checks and tries it fires off and runs roughly for about 30 seconds and then again won't start. Start to go over basic checks and several more tries of starting and still doesn't fire off. For some reason I pulled the CHMSL relay (which does happen to power a circuit to the ECM), plugged it back in and the car fired right off although the idle was a little rough and actually had to crack the throttle for a few second to keep it running. Again warmed up it runs and starts fine. Probably started it twenty times that afternoon as I played with the maf tuning, setting for over an hour one time with no problems.
Last night tried to start it completely cold , no obd2 speedo and again it won't fire up. After 3-4 crank cycles I unplug the CHMSL relay and plug it back in and it fires up no problem. Cut it off and it will immediately restart.
Spent the evening looking over the wiring diagrams to see if there is anything I missed on my fuse box swap and didn't find anything. The circuit I swapped in the fuse box runs off the crank/run relay and I couldn't track down the actual control for that relay so maybe that's the problem, although I can't see how the temperature would affect it.
Is it a tune problem? Right now I'm running basically the GM Performance stage 3 tune with torque management tweaks, but no spark/cam changes, just maf adjustments that seem to be getting close to final.
Again no DTC's other than the one misfire code from it barely running at idle. I even checked that nothing is turned off other than the downstream o2 sensor and evap codes.
Some time along the last couple of weeks, while wrapping up loose ends and tuning, I seem to have gotten the car so it doesn't want to start cold and idles roughly when in open loop. Once it warms up it starts and idles fine.
Recently I did replace the fuse box with one from a non-turbo car and had to swap one of the power circuits for the cam solenoids and turbo controls to a unused automatic transmission control module power pin, both ignition power circuits. This seemed to work fine for the first few days and I didn't notice any problems.
The first time I noticed the problem was 2 weeks ago and the car actually started and ran for about a 1/4 mile, cut off and wouldn't restart. I was trying out my obd2 speedometer for the first time so I unplugged it and after a couple of cranks it fired up and ran fine the rest of the day with me working on the MAF tuning. I did plug the obd2 speedo back in for a few minutes at the end of the day and everything worked.
Labor day weekend, it took a couple of cranking cycles to start and ran rough while cold idling. I thought maybe a tune tweak had loaded bad so I backed up a couple of iterations but it didn't seem to help the idle. I had lowered the idle quite a bit from the original non stock tune, so I bumped it back up some. Of course after playing with it a few minutes it had warmed up anyway and ran fine.
This past weekend it refused to start with the obd2 speedo plugged in, cranked over fine but wouldn't fire off. Disconnected the speedo , no change. Nothing looks funny when I plug in HP Tuners, and no DTC have popped during all this time except once a general misfire when it was barely running on idle. After a few basic checks and tries it fires off and runs roughly for about 30 seconds and then again won't start. Start to go over basic checks and several more tries of starting and still doesn't fire off. For some reason I pulled the CHMSL relay (which does happen to power a circuit to the ECM), plugged it back in and the car fired right off although the idle was a little rough and actually had to crack the throttle for a few second to keep it running. Again warmed up it runs and starts fine. Probably started it twenty times that afternoon as I played with the maf tuning, setting for over an hour one time with no problems.
Last night tried to start it completely cold , no obd2 speedo and again it won't fire up. After 3-4 crank cycles I unplug the CHMSL relay and plug it back in and it fires up no problem. Cut it off and it will immediately restart.
Spent the evening looking over the wiring diagrams to see if there is anything I missed on my fuse box swap and didn't find anything. The circuit I swapped in the fuse box runs off the crank/run relay and I couldn't track down the actual control for that relay so maybe that's the problem, although I can't see how the temperature would affect it.
Is it a tune problem? Right now I'm running basically the GM Performance stage 3 tune with torque management tweaks, but no spark/cam changes, just maf adjustments that seem to be getting close to final.
Again no DTC's other than the one misfire code from it barely running at idle. I even checked that nothing is turned off other than the downstream o2 sensor and evap codes.