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16 Mustang GT P1X lean tip in problem

Discussion in 'The Blower Bistro' started by Evan601, Jan 5, 2019.

  1. Evan601

    Evan601 Member Established Member

    Feb 22, 2008
    P-Dale, Cali
    Hello all,

    Im getting back into the mustang game with a newer car. I bought it used with a gt350 intake manifold, gt350 TB, 47# injectors, and magnaflow cat backs running a Lund N Gauge with a 91 tune, 91 and e85 tune, and straight e85 tune. Car ran fine before the install and I never felt or saw any lean issue at any point on the car.

    I have since installed a P1x stage 2 kit on it with the red race bov, Id1050x injectors, JMS pedal activated bap(50%), it now has the blowfish adapter for a stock 5.0 TB on a gt350 IM and the stock TB on it.

    The tuner is having a problem with a lean condition on tip in. From a stop in first taking off, the car goes lean (as much as 17-18:1AFR) and then comes back to 14.7 or so and when engaging into each gear there after.

    I have pressurized the system and corrected 2 leaks and now the intercooler system and engine side hold pressure. I took the pump out of the tank, clean some debris out of the fuel pump basket, checked the fuel pump filter sock, and put it back in. I have checked voltage off the wires from the JMS to see if it is sending increased voltage and gone through the JMS BAP install with a JMS tech and all are good.

    Now the car ONLY has a lean issue when starting from a stop in first gear and occasionally when at a slow roll and engaging from 2nd or 3rd gear but always when starting from a stop. When data logging for WOT pulls the car holds AFR in the 11s and 14.7 while normal cruising.

    My tuner from Lund feels its an issue with a weak pump or fuel slosh causing an initial prime issue for the pump. I have a DW400 pump on the way but I wanted to reach out to the community to see if anyone has experience any similar issues.

    I have attached data logs showing the lean tip in issue for any curious.

    log36 has 2min idle, slow rpm increase at a stop to 5500rpm, then a 3rd gear wot pull from 3000rpm to 6500rpm three times (too large for server, will upload on a file host)
    Log39 is with JMS BAP hooked up and shows lean tip in
    Log41 is with the JMS BAP unplugged and still has a lean tip in


    Attached Files:

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