tatasta
November 27th, 2009, 06:54 PM
Hello,
Recently, my stock fuel pump was going out and I ordered and installed a direct fit Racetronix fuel pump in my 99 A4 Trans Am. Prior to my old pump going out, the fuel presser ran at ~ 58# with a WOT AFR of 12.8:1. Also, my MAF calibration is spot on and my VE was working well.
Since installing the new pump, which went very well, my pressure at the rails is ~ 70 psi at idle and drops a few psi under a load. I am not using a Hotwire kit, still off the stock harness.
Anyway, the car still starts and runs decent except that my AFR has become too rich by 0.5 -0.6:1. I am assuming that the increased fuel pressure is causing this. So, the question is, what is the best way to fix this? I am not too excited about tweaking my VE or MAF calibrations since they are correct and help to make other tuning aspects accurate.
I am using FIC 33# @ 43.5# LS1 injectors that I had before changing out my fuel pump. I calibrated the IFR for them and had no problems at all except for rich off throttle coasting.
Is it possible to adjust/alter injector settings to compensate for the higher fuel pressure? And, if so, how would I go about doing that?
I have attached the tune that ran well at 58# of fuel pressure but is too rich at 70# and a log file of this tune running at 70 psi.
Thank you and any assistance would be appreciated,
Robert
Recently, my stock fuel pump was going out and I ordered and installed a direct fit Racetronix fuel pump in my 99 A4 Trans Am. Prior to my old pump going out, the fuel presser ran at ~ 58# with a WOT AFR of 12.8:1. Also, my MAF calibration is spot on and my VE was working well.
Since installing the new pump, which went very well, my pressure at the rails is ~ 70 psi at idle and drops a few psi under a load. I am not using a Hotwire kit, still off the stock harness.
Anyway, the car still starts and runs decent except that my AFR has become too rich by 0.5 -0.6:1. I am assuming that the increased fuel pressure is causing this. So, the question is, what is the best way to fix this? I am not too excited about tweaking my VE or MAF calibrations since they are correct and help to make other tuning aspects accurate.
I am using FIC 33# @ 43.5# LS1 injectors that I had before changing out my fuel pump. I calibrated the IFR for them and had no problems at all except for rich off throttle coasting.
Is it possible to adjust/alter injector settings to compensate for the higher fuel pressure? And, if so, how would I go about doing that?
I have attached the tune that ran well at 58# of fuel pressure but is too rich at 70# and a log file of this tune running at 70 psi.
Thank you and any assistance would be appreciated,
Robert