shep28

iTrader: (4)

After gunning the car a little at idle I noticed my fuel trims went from 0 to like -23 when I let off the gas. I just installed new injectors a day ago. What would cause this spike?

txhorns281

iTrader: (12)

Have you inputted the correct IFRs for your injectors? And also, do your rpms dive below idle for a sec (as if bogging) when you release TPS?

shep28

iTrader: (4)

#1- I have a 99z and installed svo30lb injectors. I multiplied the IFR table by 1.33 using HP tuners.


#2- Do you mean does it dive below idle when you unplug the tps sensor? If so, then I have not tried this.

txhorns281

iTrader: (12)

no i mean does your car surge in an out when you let off TPS and your motor speed returns back to running idle. As in, your trims indicate a rich condition, but does your car behave like it as well?

shep28

iTrader: (4)

no, the car does not surge

Another_User

I noticed some weird stuff yesterday too. I got negative spikes deep in the -40s a few times. The O2s were showing low 800s all of a sudden, no major changes in airflow, no major changes in MAP, and no change in FTC. After I drove for awhile it did not happen any more, and I never noticed while I was driving, just in the logs. It was really weird. My issues were at light cruise though. Sorry...not trying to hijack the thread.

shep28

iTrader: (4)

interesting

Another_User

I will post a log later tonight if anyone wants to take a look at this oddity in action. It's strange. Never felt a thing.

MIGHTYMOUSE

iTrader: (59)

when you let off the gas you pull a lot of vaccum.. your ifr table is not correct for these injectors at this manifold pressure.

Another_User

That sounds reasonable for his problem.