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FAST Dash voltage reading off.

Discussion in 'FAST Support Forum' started by CMD, Apr 23, 2018.

  1. CMD

    CMD Member

    Joined:
    Sep 3, 2011
    My FAST dash voltage reading is 2 volts lower than my laptop and Autometer voltage gauge after new XFI black box install with 2.05, replacing XFI 1.34 without ITC, which was working fine. I'm sure I probably missed something in the set up. Any thoughts would be appreciated.
    Thanks , CMD
     
  2. Denis

    Denis Member

    Joined:
    Dec 2, 2009
    Location:
    Mendocino County, Northern Calif
    The FAST ECU measures voltage on the yellow wire going to the ECU from the ignition switch. Measure the voltage on that wire and see what you have. My XFI never agrees with my Fluke meter, always a little low.
     
  3. CMD

    CMD Member

    Joined:
    Sep 3, 2011
    Thanks......I'll check that. So there are no adjustments to make as I had to do with the pressure sensors?
     
  4. Denis

    Denis Member

    Joined:
    Dec 2, 2009
    Location:
    Mendocino County, Northern Calif
    No adjustments to make. The calibration on the voltmeter is fixed.
     
  5. silvernblack

    silvernblack Member

    Joined:
    Dec 18, 2011
    Mine reads about 1.7 vdc low all the time. I took a voltage reading at the IGN connector and, YES, it reads about 1.7 vdc higher there than on the handheld indicator.
     
  6. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    The FAST EZ EFI 2.0 handheld should read the same voltage found on the ECU pink ignition sense wire. This is the wire the ECU/handheld gets its reading from. A lower reading on the handheld, than found on the ECU pink ignition wire, can indicate an ECU problem that will get progressively worse.
     
  7. silvernblack

    silvernblack Member

    Joined:
    Dec 18, 2011
    Hmm... My EZ-EFI 2.0 has read the same low reading since I installed it about 4.5 years ago. I will check my wiring to make sure it's nice and tight.
     
  8. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Temporarily connect the pink ECU ignition wire directly to the positive battery terminal. The handheld should then read the same voltage as read at the battery terminals. Many people just add a relay to supply direct battery power to the pink ECU ignition wire.
     

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