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Thread: No Fuel Injection on Warm Startup

  1. #1
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    Question No Fuel Injection on Warm Startup

    I have a Gen 5 LT1 that I have swapped into a C3. The engine runs great and starts when it is cold, but will not start when it is warm unless I spray fuel to get a running. After that it runs great. I am just wondering if I missed something in the HP Tuners editing menu or if somebody has run into this problem.

  2. #2
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    What fuel system are you using? Is the LT1 stock? Stock calibration? You're going to have to elaborate and share tune files if you want help.
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  3. #3
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    Quote Originally Posted by TriPinTaZ View Post
    What fuel system are you using? Is the LT1 stock? Stock calibration? You're going to have to elaborate and share tune files if you want help.

  4. #4
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    The fuel system is a pwm pump controlled by the fpcm. The ecm is unchanged from stock with the exception of vats removal and disabling the starter diag and the clutch diag. I am just unsure about what controls the injectors at startup. I have combed through alldata with no luck. I am hoping that someone has seen this issue. Thanks

  5. #5
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    Quote Originally Posted by mhassell View Post
    The fuel system is a pwm pump controlled by the fpcm. The ecm is unchanged from stock with the exception of vats removal and disabling the starter diag and the clutch diag. I am just unsure about what controls the injectors at startup. I have combed through alldata with no luck. I am hoping that someone has seen this issue. Thanks
    What about the intake manifold, throttle body and intake tube/airbox? Is that from the same LT1 engine you transplanted? Or did you make something custom? The injectors should be firing when the car is cold or warm. The stock calibration uses less spark and fuel to start that car when it is warm. My thought here is that the intake tract is too different from OEM and you're not getting enough fuel because the MAF is reading wrong. Just a hunch based on the limited information you have provided.

    If you're using the same FPCM from the LT1 transplant it should be fine. I'm also assuming you have fuel pressure key on/engine off when warm? This would confirm the low side is building enough pressure when warm.
    Resident Burble Tuner pop pop bang