Page 1 of 2 12 LastLast
Results 1 to 20 of 27

Thread: FPCM is making my life miserable.

  1. #1
    Senior Tuner IDRIVEAG8GT's Avatar
    Join Date
    Aug 2010
    Location
    Roswell, N.M.
    Posts
    1,956

    FPCM is making my life miserable.

    Hey guys, here's another thread that concerns weird things that a GMT900 series pickup does. After the addition of my new fuel system I have been battling my FPCM, and the boost referenced regulator.

    I'm running a twin Walbro 255 in tank fuel pump setup, one fuel pump being powered off the trucks fuel pump circuit, the other connected to a Kenne Bell BAP, which is triggered off of a Hobbs switch set to 3 psi boost.

    Problem is, the regulator is set to 58psi then boost referenced off the manifold.

    The FPCM however only knows low flow, normal, and high flow conditions. So I set normal and low flow to 53psi as that's where it idles at with vacuum on the manifold, and 72psi for high flow as that's 14psi boost.

    Problem is, at mid boost levels the FPCM is commanding 72psi fuel pressure but delivered fuel pressure due to the regulator is only 66psi or so as it will only be boosting 8 psi which trips a CEL of the fuel rail pressure sensor going haywire.

    How in the hell do you get around this problem? Is there a way to just disable the FPCM and let the primary pump run at 12 volts all the time without the CEL being tripped? I can't disable it in the tune
    Last edited by IDRIVEAG8GT; 04-09-2012 at 02:38 AM.
    Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.

    PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.

    Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
    618/618 motor
    906/862 spray

    Caterpillar 50 Forklift- Duramax swap

  2. #2
    Senior Tuner DSteck's Avatar
    Join Date
    Mar 2008
    Location
    St. Louis, MO
    Posts
    4,856
    Unplug the FPCM, fix the codes, and power the pumps straight off the battery with a relay for ignition on power only.

    DSX Tuning - Authorized HP Tuners Dealer
    http://www.dsxtuning.com
    http://www.facebook.com/dsx.tuning
    Just say no to bull s***.
    IF YOU WANT HELP, POST A FILE!

  3. #3
    Senior Tuner IDRIVEAG8GT's Avatar
    Join Date
    Aug 2010
    Location
    Roswell, N.M.
    Posts
    1,956
    Quote Originally Posted by DSteck View Post
    Unplug the FPCM, fix the codes, and power the pumps straight off the battery with a relay for ignition on power only.
    Even if I disable the FPCM, there's no way to turn off/get rid of the codes.
    Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.

    PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.

    Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
    618/618 motor
    906/862 spray

    Caterpillar 50 Forklift- Duramax swap

  4. #4
    Senior Tuner DSteck's Avatar
    Join Date
    Mar 2008
    Location
    St. Louis, MO
    Posts
    4,856
    If you unplug it completely, sure there is. The module itself can't throw a code, and you'll just have loss of communication, which you can turn off.

    DSX Tuning - Authorized HP Tuners Dealer
    http://www.dsxtuning.com
    http://www.facebook.com/dsx.tuning
    Just say no to bull s***.
    IF YOU WANT HELP, POST A FILE!

  5. #5
    Senior Tuner IDRIVEAG8GT's Avatar
    Join Date
    Aug 2010
    Location
    Roswell, N.M.
    Posts
    1,956
    Hmm, I wonder if I can simply pull the FPCM fuse..... Then run the existing wires that power the fuel pump off the FPCM to the terminal stub on the fuse box.

    Then that would leave the eliminate the need for the actual rail pressure sensor and all that other crap.
    Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.

    PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.

    Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
    618/618 motor
    906/862 spray

    Caterpillar 50 Forklift- Duramax swap

  6. #6
    Advanced Tuner ProTools4's Avatar
    Join Date
    Mar 2006
    Location
    sunny So Cal
    Posts
    292
    Quote Originally Posted by IDRIVEAG8GT View Post
    Hmm, I wonder if I can simply pull the FPCM fuse..... Then run the existing wires that power the fuel pump off the FPCM to the terminal stub on the fuse box.

    Then that would leave the eliminate the need for the actual rail pressure sensor and all that other crap.
    how did it go?
    NotoriouSS TAD
    DATLS7N 73' Datsun 620 LS7/HNC/TR6060/4.10/T2/2450lbs/603RWHP
    J5 - 96' Impala SS - 4700lb autocross machine
    Langston - 96' Caprice 9C1 Beater
    Rosie - 67' El Co - race truck w/ plates
    Wall-E - 21' Tesla Model 3P

  7. #7
    Senior Tuner IDRIVEAG8GT's Avatar
    Join Date
    Aug 2010
    Location
    Roswell, N.M.
    Posts
    1,956
    Quote Originally Posted by ProTools4 View Post
    how did it go?
    I'm actually still working on it now.
    Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.

    PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.

    Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
    618/618 motor
    906/862 spray

    Caterpillar 50 Forklift- Duramax swap

  8. #8
    Advanced Tuner vette_c6's Avatar
    Join Date
    Jun 2008
    Location
    Kuwait
    Posts
    390
    keep us update after you finish ,,

    specialize in: V8 Tuning (Kuwait)
    Abdullah Al-najdi
    00965 99369929
    www.youtube.com/alnajdi83
    Tuners ! Quit Raping your PE TABLE !
    instagram : alnajdi83
    best number in 1/8 mile 4.54 ( My Driving + My Tune ) !

  9. #9
    Senior Tuner IDRIVEAG8GT's Avatar
    Join Date
    Aug 2010
    Location
    Roswell, N.M.
    Posts
    1,956
    Quote Originally Posted by vette_c6 View Post
    keep us update after you finish ,,
    Well, I'm just trying to figure how to power the relay and keep everything under the hood civil. Motor is totally out right now as we lifted a head and blew a gasket at 22psi. :O

    So needless to say, there is a mess of wires strung everywhere to sort through lol.
    Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.

    PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.

    Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
    618/618 motor
    906/862 spray

    Caterpillar 50 Forklift- Duramax swap

  10. #10
    Advanced Tuner
    Join Date
    Aug 2010
    Location
    Detroit, MI
    Posts
    926
    Pins 85 and 86 power the relay.

  11. #11
    Senior Tuner IDRIVEAG8GT's Avatar
    Join Date
    Aug 2010
    Location
    Roswell, N.M.
    Posts
    1,956
    Quote Originally Posted by smokeshow View Post
    Pins 85 and 86 power the relay.
    The actual fuel pump?
    Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.

    PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.

    Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
    618/618 motor
    906/862 spray

    Caterpillar 50 Forklift- Duramax swap

  12. #12
    Advanced Tuner
    Join Date
    Aug 2010
    Location
    Detroit, MI
    Posts
    926
    I was being sarcastic haha. But yeah pretty much all relays use the same pins for the coil trigger.

  13. #13
    Senior Tuner IDRIVEAG8GT's Avatar
    Join Date
    Aug 2010
    Location
    Roswell, N.M.
    Posts
    1,956
    G'damn! that's useful to know.
    Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.

    PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.

    Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
    618/618 motor
    906/862 spray

    Caterpillar 50 Forklift- Duramax swap

  14. #14
    Advanced Tuner ProTools4's Avatar
    Join Date
    Mar 2006
    Location
    sunny So Cal
    Posts
    292
    here is my controbution

    it is yet to go on the dyno
    But it works on the rack
    hope this helps someone



    test car
    2010 Silverado 2-wheel drive 5.3
    LSX376 w/ cogged 2300 Maggy
    walbro 400 pump
    AN send return fuel lines w/ rising rate adj return reg

    process to delete FPCM with return fuel system
    Unpluged the FPCM
    *under the bed of the trucks above the spare
    *passenger side rear seat under the quarter window on the 5thgen camaro
    Large Pins 47 & 16 with around 10 gauge wire supply ground and power to the pump
    ground is Pink ...WTF~!
    Depin the connector and repin for new weather pack relay
    Pin 13 Dark Green / white stripe is the trigger form the PCM key hot.

    in HPT turn off P0230 and U0109

    go make power!
    Last edited by ProTools4; 05-04-2012 at 01:39 PM.
    NotoriouSS TAD
    DATLS7N 73' Datsun 620 LS7/HNC/TR6060/4.10/T2/2450lbs/603RWHP
    J5 - 96' Impala SS - 4700lb autocross machine
    Langston - 96' Caprice 9C1 Beater
    Rosie - 67' El Co - race truck w/ plates
    Wall-E - 21' Tesla Model 3P

  15. #15
    Senior Tuner IDRIVEAG8GT's Avatar
    Join Date
    Aug 2010
    Location
    Roswell, N.M.
    Posts
    1,956
    Quote Originally Posted by ProTools4 View Post
    here is my controbution

    it is yet to go on the dyno
    But it works on the rack
    hope this helps someone



    test car
    2010 Silverado 2-wheel drive 5.3
    LSX376 w/ cogged 2300 Maggy
    walbro 400 pump
    AN send return fuel lines w/ rising rate adj return reg

    process to delete FPCM with return fuel system
    Unpluged the FPCM
    *under the bed of the trucks above the spare
    *passenger side rear seat under the quarter window on the 5thgen camaro
    Large Pins 47 & 16 with around 10 gauge wire supply ground and power to the pump
    ground is Pink ...WTF~!
    Depin the connector and repin for new weather pack relay
    Pin 13 Dark Green / white stripe is the trigger form the PCM key hot.

    in HPT turn off P0230 and U0109

    go make power!
    :nohomohug:

    But it's under the spare?! thats where that goofy bunch of wires went lol.
    Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.

    PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.

    Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
    618/618 motor
    906/862 spray

    Caterpillar 50 Forklift- Duramax swap

  16. #16
    Senior Tuner IDRIVEAG8GT's Avatar
    Join Date
    Aug 2010
    Location
    Roswell, N.M.
    Posts
    1,956
    And also, could you simply not cut the hot wire trigger for th FPCM then wire it to the power for the fuel pump. Wouldn't that eliminate the need for the relay? And then the FPCM fuse would simply act as the fuse for the fuel pump? Or am I thinking wrong here.
    Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.

    PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.

    Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
    618/618 motor
    906/862 spray

    Caterpillar 50 Forklift- Duramax swap

  17. #17
    Advanced Tuner
    Join Date
    Aug 2010
    Location
    Detroit, MI
    Posts
    926
    Isn't your truck a 2007? Pretty sure 2007s in certain applications didn't have an FPCM, so it has to have the manual relay trigger. Pin 50 on the X1 ECM connector, DK GRN/WHT wire. That is what I am currently using until I can get my FPCM operational. Mines an 08 and still has the trigger, so you should be fine.

  18. #18
    Senior Tuner IDRIVEAG8GT's Avatar
    Join Date
    Aug 2010
    Location
    Roswell, N.M.
    Posts
    1,956
    Quote Originally Posted by smokeshow View Post
    Isn't your truck a 2007? Pretty sure 2007s in certain applications didn't have an FPCM, so it has to have the manual relay trigger. Pin 50 on the X1 ECM connector, DK GRN/WHT wire. That is what I am currently using until I can get my FPCM operational. Mines an 08 and still has the trigger, so you should be fine.
    Nah mine is an 07 but it does have the FPCM voltage modulator
    Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.

    PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.

    Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
    618/618 motor
    906/862 spray

    Caterpillar 50 Forklift- Duramax swap

  19. #19
    Tuner in Training
    Join Date
    Jan 2007
    Posts
    30
    If I remember correctly if you unplug the FPCM you have to jumper the GMLAN wires to keep the communications bus in tact. May cause other system issues if you leave the FPCM disconnected.

    When you are done with the mods, disconnect the battery and measure pins 6 & 14 on the aldl. If they are 120 ohms and not 60 ohms you need to fix your can bus. (FPCM has passthrough communications)

    John

  20. #20
    I'm running a dual pump setup on an 08. I'm using the racetronix harness and relays to power the pumps. Also bought a transistor from ADM performance to use low voltage power from the ECM to trigger a low voltage relay which triggers the racetronix relay. Remove the fuse for the FPCM and tune on the communication codes. Works great. I've got a wiring diagram around here some where of how I wired everything. ADM has used the transistor in the past to defeat the FPCM on the 2010+ camaros.