My fuel gauge started to fail. would drop to empty. Searched forum, and information led me to fuel sensor. So I replaced fuel pump & sensor assembly. With a Delphi HP10031. Then It read Full till almost 200 plus miles were put on the truck, then it would drop to half tank. then rapidly drop to empty.

Called Delphi again, and they told me I put the wrong Part in it's now an HP10074. After installation. The gauge worked for a minute or so then right back to the initial problem reading empty, low level light on, and miles to empty reading CO ( over head display )

Checked ohms on new sensor, and it works.

Used modis to operate instrument cluster, and the gauge in dash works.

Any help to solve this problem would be great. Wasting lots of money dropping tank now 3 times

 

Sounds like a bad fuel level sensor or it's wiring to me. The best way to test the gauge is to access the fuel level wire at the tank and connect it to a variable resistor to see if you can make the fuel gauge go up and down smoothly with it.

 

It's working. Delphi tech had me power it and check oms, by manually moving float up and down. So sensor at pump is working, but not reading at gauge.
Thx

 

Okay, so test the gauge like I described above...assume nothing.

 

Yes the gauge works. Any ideas on another test to do ? or what could be causing this issue. It's clearly not the pump, and sensor assembly. The first one I took out, was probably still good, because when I replaced it with the wrong Part the gauge worked, and overhead miles to empty read X amount of miles, but both were wrong. The 2nd pomp I put in was the exact same as the first one I took out. And now I have the same Empty on gauge, low level light on, and ( CO ) on the overhead display

 

All you really have left is the wiring (or connectors) between the two, and of course the ECM.

 

Thanks for your help. It's greatly appreciated. Every little bit of information helps.

 

Lets see: the gauge works - the sender works - all that's left is the wiring.


Since the gauge AND the OTC AND the low fuel light are on, I'd ohm out the ground side of fuel pump sender circuit.

If that checks out okay, then ohm out the circuit from the gauge to the fuel pump module to verify it not open or high resistance. (Your gonna have to disconnect the OTC to do that check.) Also, while in there, also ohm out that same circuit to ground to be sure its not shorted to ground.


Good luck!

 

Thank you,
That's a great amount of information. I'm not the smartest when it comes to acronyms. What does OTC mean

 

Sorry - OTC is Overhead Trip Computer.