Results 1 to 7 of 7

Thread: LFX Swap Wont Start, what am I missing?

  1. #1
    Potential Tuner
    Join Date
    May 2017
    Posts
    9

    LFX Swap Wont Start, what am I missing?

    To be fair, i could be missing A LOT!
    This is my first GM/HPT swap and i couldnt find any good single source of info for the e39a so everything ive learned is pieced together.

    Recipient car is a 1987 Nissan Hardbody or D21 for whoever is wondering.

    So i hooked up for the first time(first time using HPT) and read the stock file, saved it for safe keeping. I have disabled both VATS Patch1 and 2 under OS(after i changed view to advanced)
    I have also disabled the clutch interlock and Starter Diag under Systems.

    Lastly i went to fuel system and changed fuel pump to none since mine is indepentedntly wired for now, and FPCM Fitted to No, since im using the ECM only, no BCM or FPCM or windshield wiper control module etc.

    Now when i try to start the engine i am watching for the injector pulsewidths to be anything other than 0. They stay at 0, and the rail has 2100 ish psi of fuel pressure. It would seem that the ECU isnt firing injectors and possibly plugs. Ill do a spark check tomorrow when i have a second pair of hands.

    However i can press the gas pedal and see the throttle open and close, so the ECU is letting me do some stuff(but it behaved that way even before i deleted the VATS)

    SO... What should i check or think of next? I attatched my current tune(stock except for the changes mentioned above) and a log of me trying to start it where you can see there is no injector pulsewidth.
    Im happy to take other logs and post them here, what should i look for in the logs?

    Startup3.hptlog1.hpl

    Thanks in advance!

  2. #2
    Potential Tuner
    Join Date
    May 2017
    Posts
    9
    Update, it does have spark. Still no fuel.

  3. #3
    i think you need to send a signal to the fuel pump ..i read somewhere about having a similar problem

  4. #4
    Potential Tuner
    Join Date
    May 2017
    Posts
    9
    can you elaborate? i am sending a signal to the nissan fuel pump via a switch but im assuming you meant the ECM needs to see that the fuel pump has been turned on?

  5. #5
    Potential Tuner
    Join Date
    May 2017
    Posts
    9
    figured it out a long time ago and never posted. So consider this thread closed, i still have other problems in other threads(btw it just wasnt cranking ast enough)

  6. #6
    Potential Tuner
    Join Date
    Mar 2019
    Posts
    8
    It would be awesome if you updated the thread with the fix so others can learn too.

  7. #7
    Tuner V8 Supra Builder's Avatar
    Join Date
    Jan 2007
    Location
    Florida
    Posts
    77
    Quote Originally Posted by Erik D_lux View Post
    It would be awesome if you updated the thread with the fix so others can learn too.
    Amen! Posts like that one are really irritating for those with the same initial problem.
    Currently (2020) swapping an LM4 5.3 and an older 4L80 into a Dodge Durango. My prior projects include Chevy Gen 1 V8 into an FB RX-7, Gen 3 V8s into an FC RX-7, a MK3 Supra, a BMW E34, and an LT1 into a 280Z. Still have the Datsun, a 383 LT4 Trans Am, and some bikes.