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Thread: help solve problem

  1. #1
    Tuner in Training
    Join Date
    Dec 2007
    Posts
    46

    help solve problem

    I have a 02 3100 malibu pumping 7 lbs, the problem the car will start every time for 4 or 5 weeks straight, then one day it will not start, at first i though it was the security system , had it to the dealer a few times, they changed the iginition switch, other than that they couldn't find anything, didnt have any codes, the bigger problen till i got it hauled to the dealer and they looked at it the car started. still done the same thing, finally discovered that there was no fuel pressure with the key on motor stopped, figured it was the check valve at the pump, i was tolded, had a new factory pump installed, worked good for about 2 weeks, then one evening it would not start, happened twice in 30 minutes, each time i managed to get it started, it was flooded , could smell raw gas, smoked out the tail pipe bad , missed and idled bad till it got cleaned out, though it was the fuel regulator, i changed it, now it starts every time, fuel trims are good, but pressure at idle is about 10 lb low, car runs pretty good , but i'm down about 3 mile per gal, the problen i have NO fuel pressure with the key on, engine off. pressure checked at fuel rail.

  2. #2
    Tuner in Training
    Join Date
    Dec 2007
    Posts
    46

    fuel pressure

    Okey, seeing as i can't get a answer to my first question, can someone tell me on a 3100 malibu, when the key is on and the motor not running what holds the fuel pressure after the pump quits running with just the key on. I have no fuel pressure with just the key on, all i did was change the fuel pressure regulator, i have a new factory pump and it held pressure before the regulator change, and it still starts and runs. thanks

  3. #3
    Senior Tuner
    Join Date
    Dec 2009
    Posts
    1,084
    Either Pump No good (you say new) or Regulator Leaking down (Also ne but seems to have happened since replacement? ) or you have 1 or more injectors leaking down (filling cylinders causing flooding )

    Remove injectors and rail, prime system and see if the injectors leak

  4. #4
    Advanced Tuner gn2beatu's Avatar
    Join Date
    Sep 2011
    Location
    Germantown WI
    Posts
    414
    Check for voltage at the relay. What holds the pressure is the regulator. But there has to be pressure for it to hold. What I would do is jumper the relay as a test to let the fuel pump run continuous, then try to start it. If it starts, great, then diagnose why the relay didnt trip. But if it doesnt start & you have fuel pressure, then something is cutting the ignition and you will have to check for spark. G/L
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