Results 1 to 4 of 4

Thread: Fuel pressure and dfco question ?

  1. #1
    Advanced Tuner
    Join Date
    Jun 2011
    Location
    Montreal, Canada
    Posts
    758

    Fuel pressure and dfco question ?

    This week I installed a fuel pressure sensor for my aeroforce gauge and also to log fuel pressure with hpt.
    I have never logged pressure before on this car so I don't really know what's normal. Can someone please explain if what I see is normal.
    My understanding is that on a vette like mine the normal pressure is about 58psi. I am getting readings of 62-63 psi which I think might be slightly high due to using a racetronix harness which supplies slightly more voltage than stock. What has me totally confused is that when the dfco activates, my afr goes into the 19's (which I guess is normal), but my fuel pressure goes to 155psi.
    Is this somehow normal and what would cause this?
    I have not logged fuel pressure on any full throttle runs yet. My car doesn't go lean but I am also wondering what is an acceptable (if any) pressure drop at full throttle. In other words, how much drop would indicate I need to upgrade the system.


    Thanks in advance for any responses from the tuning experts.
    2007 Corvette C6 Vert. A6
    LME LS402, Pat G custom cam, ATI 10% OD Damper
    Circle D triple disc 2600, 3.42 Diff
    YSI, 3.0 pulley, ID 1000's
    Alky Control Meth,
    ARH 1 7/8 headers,
    1009 RWHP @ 7000, 817 RWT @ 6000

  2. #2
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    13,533
    My understanding is that on a vette like mine the normal pressure is about 58psi. I am getting readings of 62-63 psi which I think might be slightly high due to using a racetronix harness which supplies slightly more voltage than stock. What has me totally confused is that when the dfco activates, my afr goes into the 19's (which I guess is normal), but my fuel pressure goes to 155psi.
    Its possible that the RT harness has made the FP jump 5 psi, or it might be just that your pump is newer or just working better than some other cars. I wouldnt even bat an eye at that.

    When DFCO turns on the fuel injectors pretty much just shut off aswell as a few other "tables" the car is just an air pump, hence why the AFR goes to the moon.

    Are the vette's running a return style or returnless fuel system? I wonder if when the DFCO comes on the pressure builds super quick because the pump is no longer pumping past the pump itself and dumping straight back into the tank.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Advanced Tuner
    Join Date
    Jun 2011
    Location
    Montreal, Canada
    Posts
    758
    It is a returnless system. It may make sense that when the injectors close completely, the pressure would spike up like that but I would like to know if its normal.
    2007 Corvette C6 Vert. A6
    LME LS402, Pat G custom cam, ATI 10% OD Damper
    Circle D triple disc 2600, 3.42 Diff
    YSI, 3.0 pulley, ID 1000's
    Alky Control Meth,
    ARH 1 7/8 headers,
    1009 RWHP @ 7000, 817 RWT @ 6000

  4. #4
    Advanced Tuner
    Join Date
    Jun 2011
    Location
    Montreal, Canada
    Posts
    758
    Little update...
    Today I drove the car and watched the fuel pressure on my gauge, rather than log it in hpt. When in dfco the afr still went to 19, but the fuel pressure reads normal. What could cause it to read 155 psi in hpt?
    2007 Corvette C6 Vert. A6
    LME LS402, Pat G custom cam, ATI 10% OD Damper
    Circle D triple disc 2600, 3.42 Diff
    YSI, 3.0 pulley, ID 1000's
    Alky Control Meth,
    ARH 1 7/8 headers,
    1009 RWHP @ 7000, 817 RWT @ 6000