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Thread: 97 Grand Prix GTP fuel pump MAJOR issues

  1. #1

    97 Grand Prix GTP fuel pump MAJOR issues

    I have a 97 grand prix gtp, I parked it and it ran fine. When I went to start it again, it would crank but not turnover.
    Here's what has been changed / checked as of the issue:
    New fuel pump
    new fuel pump resistor
    the ECM (in the air box) is good!
    Relays and fuses are all GOOD and have been triple checked inside and out
    The battery is good, and I am getting spark to the plugs!


    The OBD II diagnostics tool reads "link error" ( have tried with 2 different devices )
    I am not getting fuel pressure, fuel pump is not turning on, and not getting electricity to pump (checked w/ test light)

    I've tried the fuel pump resistor bypass techniques, a couple different methods before, by bending the tab out and reinserting the relay, that didn't work but the one method that recommended connecting a wire to two slots in the "14" relay section turned my fuel pump on full time even when the key was off. Car still wouldn't start though, but it was the only time the fuel pump has kicked on.

    I put a new fuel pump in, with the venturi port from zz performance hoping that would do it but I guess not...
    I have a fuel pump rewire kit, i might try this, I'm still confused why my fuel pump at least turns on when I do the wire in the relay slot tech.

    Also, about the ports that the fuel pump relays plug into, one light stays lit full time in 1 out of the 5 slots in each of the 2 relay sections. When I turn the key, no other lights come on, that is supposed to be the signal to prime the pump, right?

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  3. #2
    Mud in the hvac box again FlyinGTP's Avatar
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    How do you know the PCM is good? You mention a link error, communication errors can be a big deal. Make sure the cig lighter fuse is good. It powers the aldl connector. The PCM grounds the fuel pump relay to turn on the pump. If the PCM is having issues it may no longer be able to control the fuel pump relay anymore. Do you have power and ground at the pump?
    Peeing in people's cheerios 24/7!
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  4. #3
    Light Throttle
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    I'd have to agree with flyingtp on this. While reading it sounds like a bum computer could be the cause. Has it been tuned? If so, that could be a problem, and if it hasn't, then itd be easy to just get one at the junkyard, swap it in and see if your problems are gone

  5. #4
    Full Throttle SlasherVRGR's Avatar
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    Have you checked all of the connections on the pcm? Like the plugs and ends? Sometimes they can become corroded and may need replaced or cleaned

    Edit: this would cause pcm like symptoms but the pcm could still be 100%

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  6. #5
    Mud in the hvac box again FlyinGTP's Avatar
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    Quote Originally Posted by SlasherVRGR View Post
    Have you checked all of the connections on the pcm? Like the plugs and ends? Sometimes they can become corroded and may need replaced or cleaned

    Edit: this would cause pcm like symptoms but the pcm could still be 100%
    I've also seen the wires get chaffed from the PCM being shoved in the airbox. Especially with some of the aftermarket cone filter setups.
    Peeing in people's cheerios 24/7!
    97 GTP & 00 GP GT



  7. #6
    Thank you all for the replies! I am STILL having issues! I cleaned the PCM/ECM, the ECM and all of the computer components underneath the dash were checked by placing them in an another 97 GTP, it started and ran fine.

    The cigarette lighter works... What else could it be?

    Thank you!

  8. #7
    Mud in the hvac box again FlyinGTP's Avatar
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    Quote Originally Posted by mcm0721 View Post
    Thank you all for the replies! I am STILL having issues! I cleaned the PCM/ECM, the ECM and all of the computer components underneath the dash were checked by placing them in an another 97 GTP, it started and ran fine.

    The cigarette lighter works... What else could it be?

    Thank you!
    Check and make sure all your voltage numbers are correct coming out the ignition switch. If you drop a leg you might have a cluster of fuses with like 9 or 10 volts to them.

    Do you have power and ground at the fuel pump when cranking?

    I've also seen the fuel pump sub harness get all corroded under the car at the bulk head connector.

    Cleaning stuff in most cases won't do a thing unless you have a really corroded connector. You need to do some real checking in this to determine what's wrong. If the car has factory anti theft(option in 97 not standard) then the bcm would need a theft relearn to allow the car to start.

    The car needs 3 things to run spark, fuel, air. Start by checking spark and fuel. Go from there. There are many thing like ignition modules, crank sensors and other stuff that can cause a no start situation. Once you figure out what is missing we can go from there. Also I always bypass the fuel pump resistor they are nothing but trouble.
    Peeing in people's cheerios 24/7!
    97 GTP & 00 GP GT



  9. #8
    Thank you very much for your help! Looks like I'm not getting any juice to the fuel pump, I do have spark to the plugs, everything works but no fuel pressure, no power to the pump. . . when i connect a small gauge wire between two ports of the fuel pump speed relay, the car gets fuel pressure but wont start.

    Also, this is what I discovered when I pulled back the electrical tape of the wiring that runs near and to the fuel pump speed sensor wires (green and grey) I found a lot of corrosion, but the wires seem to be intact, what do you make of this?

  10. #9
    Mud in the hvac box again FlyinGTP's Avatar
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    Quote Originally Posted by mcm0721 View Post
    Thank you very much for your help! Looks like I'm not getting any juice to the fuel pump, I do have spark to the plugs, everything works but no fuel pressure, no power to the pump. . . when i connect a small gauge wire between two ports of the fuel pump speed relay, the car gets fuel pressure but wont start.

    Also, this is what I discovered when I pulled back the electrical tape of the wiring that runs near and to the fuel pump speed sensor wires (green and grey) I found a lot of corrosion, but the wires seem to be intact, what do you make of this?
    For time being bypass the fuel pump resistor. See if you get power back there. When the fuel pump resistor is open circuit on these cars the car will start and die right away.

    Bypass the resistor and recheck some stuff. I've seen resistors right out of the box be bad. I always just bypass them now. It isn't worth the aggervation. You may ultimately have a bad relay or maybe even a blown fuse. But by bypassing the resistor it becomes a traditional fuel pump circuit and easier to diagnose.

    As for the white stuff on the wires under the loom that is normal and nothing to be alarmed about. Just about every car on the road that is at least 5 years old will have it to some degree. Now if the insulation is damaged and there is white or green powder all over the strands then that is a problem and needs to be fixed.
    Peeing in people's cheerios 24/7!
    97 GTP & 00 GP GT



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