I added a LT5 TB and I'm getting negative timing at idle. I did a search and some say to get the MAF and MAP side of things in order first before attempting anything else and I ran into another issue. MAF tuning went fine, got it within 1-2%. MAP tuning started out fine, it was very close to begin with at idle but after driving about 5 miles when I came to a stop at a light it started surging pretty good. I threw it in neutral and it still surged, drove fine home but started to surge again when I parked the car. I updated the tune with the log data I got and it still surged, the surging stopped once I turned on the MAF and put it back into closed loop and drives normal with an exception to the negative idle timing.
I'd like to see if someone could check out my tune and log file and see if there is a reason for it to start surging like this. I'd also like to see if someone can point me in the right direction to deal with the negative timing at idle and the TM going on at this time. I'm assuming the VTT needs adjustment but not sure if the MAF and MAP idle is in good shape.
Short log of surging attached and MAP tune and normal tune in closed loop
21-03-11 17-35-13.hplStep 2 MAP tuning mode.hptStep 2 back in closed loop normal driving mode.hpt