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Thread: Runing lean at top of RPM before shifting

  1. #1

    Question Runing lean at top of RPM before shifting

    the issue is that when I go WOT, the wideband will go lean gradually to like 13.xx and sometimes 14.x at top of the gear (2nd gear) and once it shifts to 3rd, the AFR goes back to normal around 12.x before I let off around 110-120mph. I had only done this 2-3 times so hopefully my motor's not busted . btw no knock retard occurred when I did the pulls.

    currently running a used walbro 255lph fuel pump with ~15-20k miles (bought it from a member on here when it had 10k miles). gtp injectors and IIRC fuel filter prolly has about 20-25k miles on it.

    here's the link of my tune and a recorded run that I posted on ls1tech. I cant seem to upload it from there to here on this laptop for some reason, maybe security is set too high. its post #21. also heres what I had changed that had no affect:
    swapped out the walbro fuel pump with a spare oem fuel pump
    new ntk WBo2 sensor
    caspers electronics fuel pump rewire



    could a worn out alternator (original 151k miles) be a possibility because if the car would sit in the garage 7-14 days w/o driving it'll need a jumpstart (currently have a battery tender jr. to charge it on days of not driving the car). my fuel pressure gauge needs a new hose as I had to cut it for another project. the next thing I was thinking was fuel filter?

    TIA

  2. #2
    Advanced Tuner
    Join Date
    Feb 2015
    Location
    Perth, Australia
    Posts
    974
    check fuel pressure isn't falling off.

    if it isn't then I'm assuming you've tried adding fuel via the MAF and/or VE table? the other thing is in some vehicles under engine>torque management>general under max limit vs. RPM the "max torque" value on some vehicles when increased from stock value can reduce fuel pump voltage

  3. #3
    ok, i'll check fuel pressure when I get a chance. yes I tried adding loads of fuel in the 9K range in the MAF and it did not difference as well as added a bit more in the VE table. i'll have to check the engine>torque management>general under max limit vs. RPM the "max torque" value but I had installed a caspers fuel pump hotwire and it didn't make a difference fwiw. before I dropped my car off at the mechanic, I swapped out my GTP injectors and installed the factory ones as well as replaced the fuel filter. I was going to do another pull before dropping the car off but we had been hit recently with nor'easters and when it was over the schedule date for me to drop the car off came up. the car's currently at my mechanic getting a stall installed.