Fuel gauge erratic movement

Discussion in '2nd Gen - 2003 - 2006' started by Jdcline54, Dec 6, 2018.

  1. Jdcline54

    Jdcline54 Member

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    Recently On my 03 5.4l,the gas gauge has gotten all screwy.. It happens intermittently while driving, parked on flat, parked on hill...

    I noticed one day that my gas gauge was moving.. Not just a little, but a lot... So i started paying more attention to it to try to verify what I thought I was seeing and a couple days later it happened. Was sitting in a parking lot with the engine running and the gauge going down from about the 3/4 mark to half and back up. It did that a few time and then stopped and went back to 3/4,where it stayed. The next morning it did the same thing, only at the end it went all the way down to empty, bounce a few times to random spots and settled at about a quarter tank.

    I know I had about 3/4 of a tank as I had filled up 5 or so days before hand. So really I assumed that I had that mush based on past experience.

    I've been watching this issue for a couple months, sometimes it doesn't do it at all. And sometimes it's really bad. Like right now I am 180ish miles into a full tank, yet the gauge reads a under quarter, when it should be closer to the half mark

    Anyone else ever experience this?
     
  2. Hamfisted

    Hamfisted Full Access Members

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    Are you the original owner ? Is it the original fuel pump assembly in the Expy ? It's probably just the fuel quantity sender getting ready to fail. That's all part of the fuel pump assembly. If it is the original fuel pump assembly in the Expy I'd just replace the whole assembly and be done with it. You can make a quick inspection of the wiring harness under the driver's side of the Expy and see if you see anything out of the norm with the fuel pump harness, just going by the age of the truck my bet is on the sending unit going bad.
     
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  3. Jdcline54

    Jdcline54 Member

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    Thanks! I figured the same thing as I am not the original owner and don't know the history... but I've never seen a sending unit go bad slowly, only fail all at once. So I thought I'd ask for a second opinion.
     
  4. Don Hall

    Don Hall Supporting Member Supporting Member

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    If the cost of replacing the float/pump doesn't interest you, use trip mileage divided by 10 gallons (conservative estimate) to determine fuel usage.
     
  5. 1969 Bulldog

    1969 Bulldog Member

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    Mine failed in my '04 while it was under warranty. Would have cost a lot in labor otherwise. Requires dropping the fuel tank to get to it. Fortunately, haven't had a problem since.
     
  6. XR4Ti

    XR4Ti Active Member

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    I had an erratic fuel gauge on my 2005. Seemed to happen more in the winter (started end of 2 winters ago and during last winter, would go away in the summer except for once or twice when it was really cold and damp), possibly because of moisture from snow/salt/water getting into the big connector on the frame in front of the rear wheels and not being able to dry out. Can't remember which side it is on, but after disconnecting, drying out, and retaping, the problem went away. I also noticed the plastic clip that secured it to the frame was broken so the connector was hanging and exposed more than usual so I tied it higher to get more protection from the elements. So far so good.

    Symptoms were that I would fill up the tank and the gauge would drop to about 3/4-7/8 of a tank and would just consistently read low as I burned through the tank. Messed up the consumption calculator too. I believe I also did some electrical troubleshooting using the manual and everything seemed ok.
     
  7. lbv150

    lbv150 Full Access Members

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    Mine failed in the '04 a couple of years ago, just doing the mileage thing and filling at 300 miles. Someday I'll change the pump assembly.
     

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