Fuel Guage/Sender problems...

[Jgreemo]

It seems my fuel guage/sender went bad. Was working fine until I ran into the store and when I started it back up, the guage went to the 3 o'clock position.
I found a vendor for the sender, but before I drop both the tank and the money, I wanted to see what the board had to say about it. Does this sound like a sender problem? If it had a stuck float, I can imagine it would stay at the 1/2 tank line where it was before. Or is it the guage?

Any ideas would be appreciated.

Thanks,
Jon

[NH2112]

I can't remember whether GM fuel senders have 0 ohms when empty or when full, but if you momentarily ground the sender wire while someone watches the gauge, it should peg either empty or full if the gauge is good. If it doesn't, then the gauge is bad. The most common problem is the ground wire between sender and frame corroding. Another one is the sender wire being pinched between a body panel and the frame, usually without breaking the insulation.

[britannic]

My gauges jump south when I start up and then assume their proper positions once key is released, occasionally one will stick and I need to tap the glass to unstick it.

[john8662]

Another thing it could be is the resistor on the back of the fuel gauge if the gauge checks bad. On my truck, the gauge would still work, but would only read 1/4 tank when full, 1/8 tank meant half full, etc. when you pull the gauge out of the dash it has a chalk looking resistor on the back of the gauge on the connecting pins. There is an aftermarket replacement resistor for that. I purchased on at a local performance shop and if fixed it perfectly. I'll look up the resistor part and post it here if thats whats needed..

[Jgreemo]

Thanks for all the help.

Again, the gauge is pegged over at the 3 o'clock position. With the ignition off, it slowly falls back to near full, but turn the key and it swings back around to 3. I'll check both the ground and sender wires to see if there is an short.

Keep up with the great ideas!

Thanks again,
Jon

[mhagie]

When I was in the middle of converting my 84 gasser to diesel I had the engine wiring harness off to adapt a diesel harness to the gasser firewall connector (had to change a couple of wire locations on firewall plug).
Was also working on gauges for my banks turbo when I hooked a temp wire from battery to + bat cable, turned on switch and looked at gauges and they were going nuts,oil pres, water temp, and fuel all were moving clockwise big time, all ended up at between 3 0-clock and 5 before I could shut off ign switch.
Needless to say it scared me big time as I couldn't figure out what I could possibly have done wrong,turns out I had only pushed engine harness plug only part way into connector block, the bat term was connected but none of the sending units were making contact.
Moral of story,check sending unit wire which on mine is a pink wire that exits the harness right above steering column ,engine side of firewall,and proceeds down drivers side of frame rail.
My diesel harness came from a 85 suburban and thats where it ran, same as the gasser pickup.
Good Luck :D

[Jgreemo]

Found the problem with the gauge. Turns out the back of the instrument panel had come loose. Stopped for gas (didn't really know how much I had after all) and when I turned on the headlights, the dash lights flickered. Reached under the dash and found the back panel had come loose. Pushed it back on, lights came on and gauge returned to indicated fuel level. Can only surmise the gauge was not grounded with the back panel loose.

Thanks for all the help!
Jon

[HANK1948]

Another thing it could be is the resistor on the back of the fuel gauge if the gauge checks bad. On my truck, the gauge would still work, but would only read 1/4 tank when full, 1/8 tank meant half full, etc. when you pull the gauge out of the dash it has a chalk looking resistor on the back of the gauge on the connecting pins. There is an aftermarket replacement resistor for that. I purchased on at a local performance shop and if fixed it perfectly. I'll look up the resistor part and post it here if thats whats needed.. JOHN, thats exactly what mine is doing what is the fix your talking about? and were can I get it?

[Jgreemo]

Hi Hank, these trucks use a printed circuit board for the dash wiring. The back of the dash assembly holds various contacts and of course, the dash lights. The whole sandwich is held by some clips and in my case it came loose. I reached up behind the dash, up by where the speedo cable connects to the guage and gently pressed it towards the front seat. It snapped into place and the guage came back to life. If it's a chronic problem, I imagine you might have some broken/missing clips and the dash might have to come apart for a permanent fix. Beyond that, it could also be a wiring problem with the fuel tank as mentioned in the other replies to the post. For me, it's been two years and no problems. Good luck.

[john8662]

HANK,

go to www.fix-a-gauge.com (http://www.fix-a-gauge.com) They should have what you're looking for, Remember that being a suburban you'll probably need the one that fits the 81-87 truck body style fuel gauge, since the suburbans didn't change body style until 92, where the trucks did in 88.