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Fuel Gauge Stuck on FULL.

The Butcher

The Butcher

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Texas. In a van, down by the river!
The fuel gauge on my '90 K5 is stuck on full. Actually, past full in the 3 o'clock position. It has always gone past full when I fill it up, and it would swing noticeably back and forth as the fuel sloshed around during driving. Not a big deal since it still worked to show me how much fuel was left in the tank once the gas stopped moving around.

For some reason after my last fill up and some subsequent driving it has stuck at the 3 o'clock position past full. Anyone know why this would be? I assume the float is probably stuck or something, but not sure how to fix it. Any suggestions would be appreciated. Thanks.
 
readymix said:
You have an open in the circuit somewhere. Check all the connections and trace the wires.
Click to expand...

Yep full= 0 ohms of resistance. If you have no power through the circuit the gauge will fail full or higher as full on the gauge is a little more than 0 ohms.

Ira
 
I though full was 90 Ohms...

Then again I don't really remember as I changed mine a long time ago. It would make sense though as an open would be infinate Ohms. A short would be 0 Ohms.

I do know for a fact that an open pegs the gauge past full
 
I've never seen mine on "F". I always run out of money before the pump stops:doah:
 
The pump usually shuts off before I get to full b/c the pumps around here seem to have a $75 limit on them. I guess the increased gas thefts have made the stations limit the max amount you can get at one time.
 
Not to hijack or anything, but I'm putting in a new fuel gauge (autometer) and was wondering if anyone knew which wire on the tank was the sending unit. Or should I replace the sending unit too?
Thanks and sorry...
 
my guage did the same thing about 2 years ago, i found two problems,
the first was that the fuse kept blowing for the guages and dash lights, that was just wonderful, and causing the guage to reed full.
Second, down all the way back by the tank their was a bundle of wires tucked next to the dvrs rear frame, and one of them was for the sending unit.... sure enough it was chaffed through and touching the frame.... yuck and it was badly corroded.
i say check the fuse and trace the wires, like previously stated.

LUKE
 
There is a connector near the tank (single prong if carbed) that you can disconnect, pretty easy to test from that point either direction.

Wire is usually pink for carbed applications, can't recall what mine is with the TBI pump.
 
dyeager535 said:
There is a connector near the tank (single prong if carbed) that you can disconnect, pretty easy to test from that point either direction.

Wire is usually pink for carbed applications, can't recall what mine is with the TBI pump.
Click to expand...

On TBI truck the tan wire is for the pump, the red is for the sending unit. My original '77 sending unit wire was tan. When I converted to TBI the gauge and pump didn't work too good when hooked up in reverse....:doah:
 
mouse said:
On TBI truck the tan wire is for the pump, the red is for the sending unit. My original '77 sending unit wire was tan. When I converted to TBI the gauge and pump didn't work too good when hooked up in reverse....:doah:
Click to expand...

Thanks for the info. I'm going to try and find time this weekend to track down the problem.
 
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