recently installed a power programmer and the car ran great and picked up power but not to long after that i noticed a engine light only when the accesories were turned on but not when the car is running, i checked the number (it only shows up on the programmer, not on a regular obd-2 scanner) and it said it had something to do with the B negative ground for the a/c, also after having had the programmer installed the oil pressure fluctuates when the a/c is on and the car runs hotter than normal and seems to have knock retard pulling timing away to lose power. i was wondering if anyone else has had these kind of problems

 

Can you post more info - type of programmer, "canned" tune or did you make additional changes, the DTC code, mods etc? You could try returning the PCM to the stock tune and see if alleviates any of the problems you're having.

 

Best thing to do with tunes like hypertech/diablo is return your car to stock, and use it only for adjusting tires/wheels/gears/automatic tranny shift points.

 

the programmer is hypertech, i'd like to return it to stock but i am waiting to put 3.73's in the car and it's got a shift kit in it, i'd like to just adjust those 2 things but it doesn't give you the option to only reset the computer with out tuning it too, to my understanding at least

 

When I had HPP3 I was able to adjust for gears, fans, shift firmness (no shift kit, don't do both) and shift points independent of their tune. I don't think the tune has anything to do with your fluctuating oil pressure and running hotter though. Try restoring your stock tune, then just changing the parameters you want. Should work unless the new units are different. If your SES light is on while running have the code read, something's wrong.

 

If I remember right, when I had my HPPIII there were two options to start. You could install the tune as is or modify the settings. If you chose the second, you could tell it not to install the performance tune and then go through all of the options (tire height, fan settings, shift firmness, etc.) and install the changes you made. Double check the instruction manual that came with it if you have it.