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Thread: Fuel Pump Prime Time

  1. #1
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    Default Fuel Pump Prime Time

    Hello,
    Brand new to the forum and very new to tuning as well. I have a question I feel I am close to the answer on but would like to hear it from the pros. I have a 97 Camaro F Body car with 24x LS1 Coils and PCM. I have upgraded the entire fuel system for forced induction. As of now when I turn key on fuel pump turns on fuel pressure makes it up to rails but only produces about 15-20psi fuel pressure on the aeromotive regulator. If I attempt to start it wont fire at first. So the way I have been starting it is turning key multiple times key on key off key on and will eventually get the desired 50psi on the fuel rail and start right up from there. I do have an inline check valve in the -8AN line so once pressure is achieved it does not drop off. I believe if I can just make the initial run time of the pump longer(in seconds) I will obtain the proper pressure first key on (wait the 10sec or whatever) and the vehicle will fire right up.
    So is the B3201 the correct parameter to change? It is in unit of grams. I could have sworn I have seen something in mSeconds before. Any help is appreciated. Thanks in advance, hope to pick some brains with VE tables in the near future.

  2. #2
    Joe (Moderator) joecar's Avatar
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    Sounds like something is not right with the fuel pump and/or regulator...

    LS1A/LS1B PCM's (IFR table) expect rail pressure to be 58 psi.

    Typically, on key on, fuel pump runs for about 2 seconds (or less).

    Sounds like your check valve is trying to help, but something else is wrong.

  3. #3
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    Default

    Quote Originally Posted by joecar View Post
    Sounds like something is not right with the fuel pump and/or regulator...

    LS1A/LS1B PCM's (IFR table) expect rail pressure to be 58 psi.

    Typically, on key on, fuel pump runs for about 2 seconds (or less).

    Sounds like your check valve is trying to help, but something else is wrong.
    This is an LT1 so the same rules don't apply, I don't believe? My car doesn't "Need" 58psi to start or idle. 2 seconds of pump run time barely gets the fuel through the -8AN lines to the dual feeds to the rails, through the rails, back through the -6 return lines to the regulator. Lots area to fill w/fuel I suppose. It just needs more run time on the intital pump turn on. If I cycle the key 3 times(in run position) it will reach its 45psi(and maintain) what I have the regulator set to and it will fire up then when you turn the key forward to start position.
    If I had the fuel pressure regulator set to 58psi it would probably need a 4th key on/key off to ultimately get to that pressure. It is far from a stock fuel system so I would think running the pump longer initially isn't that absurd. I have ridden in some high HP built imports that run the fuel pump for easy 8-10sec before cranking.
    Old tuner had bumped up the time pump intially ran by a second or two before I moved, but it just isn't doing the trick.

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