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Thread: Inline fuel pump problems in Commander 950 setup.

  1. #1
    kz6bd1 Guest

    Default Inline fuel pump problems in Commander 950 setup.

    Mechanical newbie trying to work on a Commander 950 setup on '81 Camaro with 350 crate engine. Had a mechanic install the system but am now trying to setup software, tune engine, etc. myself.

    Going relatvely well until I had to do some work under the car and jack up the passenger side. The inline fuel pump (black, came as part of the Commander 950 package) is mounted on the frame on the passenger side below fuel level so gravity feed should be OK (though in the jacked position the fuel probably drained away from the pump). After returning the car to the ground, the fuel pump no longer works; at least it does not make the normal hum as when its pressurizing the system. The Holley Commander software shows the fuel pump to be engaged (highlighted in orange) and I even hear a click which could be the relay but almost sounds like it is coming from the fuel pump area.

    Is it possible a safety switch has disabled the fuel pump since it was not in the normal orientation for a while? Is it possible that the fuel drained away leaving an air bubble in the system; will the pump not run if it doesn't detect fuel? How can I clear it if that's the case? Have tried pressurizing the system several time (turn key off for several seconds then back on with no crank so that fuel pump is activated, again no hum unless it is super quiet).

    This has actually happened once before in the same situation (car jacked up on passenger side) but seemed to fix itself after several minutes of checking relays and probing voltages at the pump. I did not find anything out of line and did not change anything, it just started working again so I assumed it was a fluke. This time, I waited much longer but it is still not working. When the pump is/was working it seems fine, pressure is good, sounds good, no reason to think it is going bad.

  2. #2

    Default

    First thing you need to do is put a volt-meter on it and verify it has voltage. Look for corrosion/signs of distress at the relay or fuse.

  3. #3
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    Default

    Quote Originally Posted by kz6bd1 View Post
    Is it possible a safety switch has disabled the fuel pump since it was not in the normal orientation for a while? Is it possible that the fuel drained away leaving an air bubble in the system; will the pump not run if it doesn't detect fuel?
    The C950 doesn't have any such safety switch.
    Also, an air bubble won't stop the fuel pump from running.

    I would inspect the wiring for damage from jacking the car.
    Last edited by Danny Cabral; 03-09-2010 at 05:16 PM. Reason: additional infomation
    May God's grace bless you in the Lord Jesus Christ.
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