s-10 fuel gauge pegs on full when key turned on


captantone
04-22-2010, 08:49 PM
1993 s-10 pickup, installed new fuel pump, new sending unit, when the key is turned on the gauge pegs over on full, anyone seen or dealt with this before? thx in advance for your time.

MagicRat
04-22-2010, 10:00 PM
The wire coming from the gas tank sender unit is shorting to ground somewhere.

marinemandonnie
04-24-2010, 08:09 PM
I understand what you said about the wire from the sender shorted somewhere, however, and this is where it gets interesting to me. I have pulled both wires , by that i mean the wires from the fuse panel all the way to the tank sender and fuel pump and separated them from the harness. The darn gauge still pegs full. Now if i disconnect the wires from the sender and fuel pump and ground the sender wire the gauge goes to empty. Question, do i have a faulty sender or where else could the problem lie. My son, captantone posted this question for me yesterday and is unable to post details so with his instructions I am now able to post myself. Thanking you again - Marinemandonnie

j cAT
04-24-2010, 08:17 PM
I understand what you said about the wire from the sender shorted somewhere, however, and this is where it gets interesting to me. I have pulled both wires , by that i mean the wires from the fuse panel all the way to the tank sender and fuel pump and separated them from the harness. The darn gauge still pegs full. Now if i disconnect the wires from the sender and fuel pump and ground the sender wire the gauge goes to empty. Question, do i have a faulty sender or where else could the problem lie. My son, captantone posted this question for me yesterday and is unable to post details so with his instructions I am now able to post myself. Thanking you again - Marinemandonnie

hook up the old fuel pump and move the sender wiper to see if it is the new pump assembly that is ng...////who is the manufacturer of this fuel pump?

old_master
04-24-2010, 08:49 PM
If the sender wire is open, the fuel gauge goes to full.
If the sender wire is shorted, the fuel gauge goes to empty.

Check the sender ground wire, (black) at the fuel pump module connector. Resistance should be 5 ohms or less to ground. If the ground wire resistance is OK, and you ground the sender wire, (purple) at the fuel pump module, if the gauge goes to empty, the fuel level sender is faulty, (open circuit).

marinemandonnie
05-01-2010, 08:15 PM
Many thanks to Old Master, J cat and MajicRat. Your combined advice pulled me through. Yes the problem was a faulty sending unit. When i hooked up the old one and flopped the float around the gauge worked fine. Trouble was bad resistor in the new Spectra sending unit. Lesson learned Try it out before installing it in the tank!!!!. Thanks again guys. Donnie. If it Aint broke dont fix it

Chevy Nova
05-20-2010, 07:11 AM
old master
sorry to ask a question on someone elses post. What if you have more reistance does that mean the black wire is bad? Thanks

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