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Thread: Feature request, custom control over fuel transfer pump relay

  1. #11
    New Member
    Join Date
    Jan 2015


    Quote Originally Posted by THEFERMANATOR View Post
    No, the transfer pump will look for change in the primary and secondary level units. If it doesn't see the secondary level showing the level dropping, and the primary showing the same or increasing, it will most of the time default your fuel gauge to empty, or shut the transfer pump off thinking the transfer pump relay is stuck on. I ran into this on a DURABURB tune I wrote. On the economy tune he goes so far before the level really changes, it causes all kinds of issues. That and at first he had the stock Y to the 2 tanks which allowed fuel to slosh forward, and when it saw this, it would disable the transfer pump. it is a finicky system to say the least. That, and you have to have a cab and chassis fuel segment for the ECM to even enable the transfer pump.
    Okay that answers my question Thanks TheFermanator

  2. #12
    New Member
    Join Date
    Dec 2014


    The truck is a 2003. OS number: 15189044

    As an update I ended up using the relay but hard wired the relay control to ignition switched power. I tried to use the DSP output but it would not sink enough current to switch the relay so I would have needed to install another relay/circuit. Works well though it is annoying to have the pump running when the ignition is powered and I'm doing an ECU flash and it would be nice to have the safety feature where the pump shuts off when the engine shuts off. Probably not as critical with diesel as with gasoline.

    For anyone looking to do the same relay "reuse" you will need the fuse box pins to replace the existing ECU connection to the relay and will need to connect from the switched side to power the pump. The fuse box pins are Delphi Metri-Pack 280 series and the part number is: 12129061. I found them on Mouser part number 829-12129061. Ended up with a nice clean install. Once you pull the relay block you can get to all the pins and easily swap them around.

    I also tried messing with the second tank values in EFI Live. I was never able to get the relay to switch on no matter what I set for tank sizes or fuel level calibrations. I suspect my OS does not have the second tank code enabled. Either way I gave up on that path.

  3. #13
    Junior Member
    Join Date
    Jul 2013


    Quote Originally Posted by GMPX View Post
    Just so you don't sit there forever waiting, it will probably never happen, sorry.
    too bad, really would be the right way to get it done.
    04 LLY Crew cab
    Complete LBZ intake
    EGR is gone
    PCV delete
    resonator delete
    EFI Live DSP5

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