Saturn alternator swap causing fuel trims to be off?

[da_reeseboy]

My car has been mostly parked for the last 2 years, with me driving it only a little to keep the tires and drivetrain rotating. In that time, I have swapped the alternator, upgraded injectors, and reprogrammed my chip for the larger injectors. Now that I've finally got the car back on the road I'm noticing my fuel trims are off.

I used ecmlink wiki to base my injector settings - baseinjectordata [ECMTuning - wiki]
I have the PTE/Delphi 1000cc injectors and have repeatedly checked the settings.

The alternator swap leaves 2 wires for the ecu disconnected - pin 41 (Alternator FR) and pin 33 (Alternator G) http://www.dsmtuners.com/forums/new...4-pin-alternator-connector.html#post151624578

I have noticed my fuel trims adding a decent amount of fuel - short term up to 18 and long term up to 9. I noticed today as I made another chip that the injector latency is based on voltage, which has me wondering if the disconnected ecu wires on the alternator provide what the alternator bases its system voltage on and therefore are messing with the injector latency adjustments. I had to disable a check on the ecu that was causing a CEL with code P1500.

Thoughts?

 

[DIMONDSTAR77]

alternator might be bad, had a bad one on my car that caused my fuel pressure to jump 20 pounds, after replacing fpr and going all through the fuel system found out the voltage regulator was bad on the alternator. replaced it and fuel pressure went back to normal. just my .02

 

[da_reeseboy]

That's an interesting scenario - thanks for the input... I can't see how a bad regulator would cause a 20# jump in fuel pressure, but you can't argue with results . My fuel pressure is right on the mark, and when I check the voltage from the alternator its 14.5-15.1 depending on load and ambient temp... which is why I did the switch to the Saturn alternator.