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-   -   No power to fuel pump relays or fuses on '98 Cavalier (https://www.askmehelpdesk.com/showthread.php?t=757508)

  • Jul 9, 2013, 10:30 PM
    sharktat
    No power to fuel pump relays or fuses on '98 Cavalier
    My 98 cavalier just quit running parked it one night then the next morning it would not start.The fuel pump will run if I put power to it but upon inspecting relays and fuses I have no power to either of them.I have no blown fuses .I was told I should have power to one of the terminals on the relay but there is no power at all to the relay under the hood or the fuse inside the car.Anybody got any suggestions
  • Jul 10, 2013, 05:29 AM
    Stratmando
    Did you look for the voltage with the Key on? You may have a blown fuse. I believe the ICM gives the relay the ground.
    If you have a Tone generator, hook to the terminal that should be live, and look for the tone at the fuse panels.
    The service manual will show on the schematic.
    I will see if I can find something.
  • Jul 10, 2013, 05:49 AM
    CaptainRich
    The fuel pump is always grounded and power is controlled through the Fuel Pump relay by the Powertrain Control Module (PCM).
    Power to the relay is through the F/P-INJ fuse (20 Amp) and that fuse should be HOT (B+) with the key in the RUN or ON position. If that fuse is good but you have no power to the relay, look for an open circuit between the fuse and the relay.
    Does the fuel pump PRIME when the key is on?
  • Jul 10, 2013, 06:16 AM
    Stratmando
    Captain, were you thinking I was saying the Fuel Pump got its Ground from The ICM?
    I was speaking of the Relay getting its ground from the ICM, and is what switches the fuel pump on and off.
    The relay socket needs a hot for the relay, and a hot to power the pump, I think maybe still an unfound fuse?
  • Jul 13, 2013, 06:38 AM
    sharktat
    Quote:

    Originally Posted by CaptainRich View Post
    The fuel pump is always grounded and power is controlled through the Fuel Pump relay by the Powertrain Control Module (PCM).
    Power to the relay is through the F/P-INJ fuse (20 Amp) and that fuse should be HOT (B+) with the key in the RUN or ON position. If that fuse is good but you have no power to the relay, look for an open circuit between the fuse and the relay.
    Does the fuel pump PRIME when the key is on?

    I have no power to the fuel relay or F/P -INJ fuse at all with the key on or off but I do have power to everything else
  • Jul 13, 2013, 07:14 AM
    odinn7
    This is a long shot as I haven't dealt with Cavaliers beyond 96 as far as trouble shooting goes but...

    I learned in tech school back in the early 90's that if the Ignition Module is fried, the fuel pump will not initialize (on most GM's at the time). There needs to be a reference from the Ignition Module in order to allow the fuel pump to kick on. I know that many GM's, especially Cavaliers, were subject to bad Ignition Modules.

    Are you getting spark when you crank the engine?
  • Jul 14, 2013, 09:17 PM
    sharktat
    I found out it was the ignition switch that went bad.Replaced it and it started right up.
    Thanks for the input guys

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