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Thread: Losing Fuel Pressure

  1. #1

    Losing Fuel Pressure

    I have a 383 fuel injected with a rear mount gt45 about ready to go to the tuner, it has a mail order start up tune. I have been trying to get the car ready for a dyno tune. Here is my problem. The car is running very fat 10to 1 AFR. I have been running the car against the line lock and at about 4000RPM the fuel pressure drops about 20 pounds to about 20 to 25PSI. I am running two Walbro pumps on two different circuits. I checked all the fuel lines and the fuel filter and actually changed the line between the pump and the fuel filter because the line had a couple kinks. Any suggestions would be appreaciated.
    __________________

  2. #2
    Senior Member RACING JUNKIE DirkaDirka's Avatar
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    Does the car have a fuel cell? If so does it have foam in it?? If so how old is the foam?? The foam could be clogging up the fuel pick up at the pump.
    Its all fun and games till someone loses a nut!

    http://www.racingjunk.com/profile/400466

  3. #3

    Fuel

    It is a stock tank that is clean.

  4. #4

    Pump

    Put an order for an Aeromotive A1000 today I hope that solves my problem.

  5. #5
    Senior Member RACING JUNKIE
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    Re: Losing Fuel Pressure

    Quote Originally Posted by skipjobe
    I have a 383 fuel injected with a rear mount gt45 about ready to go to the tuner, it has a mail order start up tune. I have been trying to get the car ready for a dyno tune. Here is my problem. The car is running very fat 10to 1 AFR. I have been running the car against the line lock and at about 4000RPM the fuel pressure drops about 20 pounds to about 20 to 25PSI. I am running two Walbro pumps on two different circuits. I checked all the fuel lines and the fuel filter and actually changed the line between the pump and the fuel filter because the line had a couple kinks. Any suggestions would be appreaciated.
    __________________
    Fat? You mean lean right?
    What size lines do you have going to the pumps and reg?


    Do you have a bypass or a vacuum controled regulator?
    Sounds like a fuel regulator problem to me.
    On a Vacuum controled unit , make sure you have full manifoild vacuum going to it.
    Also check for a voltage drop to the pump(s) and also the pump grounds.


    Cp
    ***IN GOD WE TRUST***

  6. #6
    Senior Member RACING JUNKIE
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    May 2003
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    How about a new guage to check the pressure ?

    AF is fat and is not where it should be, what type of monitor do you have on this ?
    David Lanning
    IHRA NHRA 387B

    Fleenor Racing Transmission
    419-280-1406
    Lanning Electric
    Complete Drag Car Wiring
    APD Race Engines
    www.apdracing.com

  7. #7
    Senior Member SENIOR BUILDER
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    Nov 2004
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    What Walbrow pumps you got? I asume 340m. With 2 pumps running 2 feed lines to what, each side of the rail with what, 1 reg on the left side and what size return line? What size feed line? What injectors? How about a hot wire with a relayd good 12v close to the pump.

    Craig

  8. #8

    fuel

    I have a wide band (Innovate LC-1) 2 Walbro 340's with a y in the tank to the stock 3/8 stock fuel line. The regulator is a factory stock with a kit to make it adjustable. It has a vacuum line to increase fuel. It also has a return line. I have #12 wire on a relay running to one pump and the stock circuit to the other. It is idleing at about 10 to 1 I am running it up on the line lock and watching the tack and someone is watching the fuel pressure under the hood, so I cant watch the AFR or boost to much going on.
    Last night I ordered an Aeromotive a1000 pump and matching regulator.
    I am hoping this will solve my problem. Next will be 1/2 inch hose and modify the fuel rails to a double inlet. I need my money tree to have another crop.

  9. #9
    Senior Member SENIOR BUILDER
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    Id stick with the walbro's befor id run an aeromotive junk. Intank double pumpers are suposed to be staged. Only run 1 at idle and cruize but turn on the 2nd at full throttle.

  10. #10
    Senior Member SENIOR BUILDER
    Join Date
    Nov 2004
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    118
    After rereading your setup, your gonna need at least a #10 feed and a 6 return. I run a Weldon 2015 pump on the 86 GN with enuff fuel to break the crank @ 35 lbs boost :roll:
    You might wanna run the 2025-a.
    I'd return the aeromotive and get a weldon, there suposed to be the slick shit. A little pricey, but you only wanna do it once
    http://www.weldonracing.com/product/...Outlet%29.html

    Craig


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