Float Assembly Problems... Still.

[Knucklehead97]

I'm still stumped by my float assembly not reading. I havn't yet gotten the gas low enough to take the pump and all out without flooding myself with gas. At first I thought the float just wasn't floating, but then I noticed that my guage is always reading over full. Which would mean the float would have to be floating, or stuck. Now I'm wondering if it's my guage, or wiring, or maybe a relay or fuse?

 

 

Thanks

[ComancheKid45]

If the gauge is pegged over full, its likely pointing to a ground issue in the circuit. Easy place to check and refresh a common ground is behind the Left tail light ;)

[Eagle]

Easy check on the gauge.

 

Disconnect the plug in the wiring where it exits the gas tank. Turn on ignition (do not start engine). Where's the needle?

 

Take a jumper wire and connect the fuel sender wire on the chassis side of the connector to a known good ground. (There are three wires. Black is ground. The fat wire is the fuel pump. The third -- whatever color it is -- will be the sender.) Now where's the needle? It should be at the opposite end of the scale as when you had an open circuit.

[Knucklehead97]

Thanks for the replys :yes: I'm hoping that it's just a bad ground or something cause float's are pretty hard to come by it seems. I'll try these tomorrow and hopefully be able to keep up with my gas now.

 

 

Thanks

[Goose]

Not trying to thread jack, but a related issue. Why would a gauge, when the tank is full, only read 3/4 of a tank?

[Knucklehead97]

I disconnected the plug and turned the key. It still was reading over full. It's right on top of that right screw on the gauge. And it stays there even when the trucks off. I havn't connect the fuel sender wire to a common ground yet to try, but I am tomorrow if it'd stop raining :fs1: Could it maybe just be a broken gauge? I'd expect the gauge to be reading under empty if I had the truck off.

[Biotex]

Is the needle on the guage possibly stuck because it is physically touching that screw you mention?

It should go to empty with the connector unplugged. As others have stated, when it goes to full, it is a short to ground on the sender wire. Try a continuity test from ground to the sender wire and see if you have a short to ground condition in the wiring harness from the back of the guage to the fuel sender unit. You could probably do a decent physical and visual check by tracing the wires as best you can.

If no short to ground, then your guage is bad.

[Biotex]

I just looked at the diagnostic procedure in the 88 electrical manual and there are two checks.

 

With key in run

Disconnect connector C139 and needle should go to full if there is a good ground at G107. If it doesn't, then replace sender.

At C203 terminal 15, should read 0-88 ohms with C139 connected. If it reads this value, then replace the guage. If not then there is an open to the sender.

 

Hope this helps.

[Knucklehead97]

I'm going to check all the wires and make sure everythings grounded right and if the gauge isn't stuck. And try a couple of the checks to just be positive. Then if not I guess I'll go to a junkyard and pick me up a XJ 120 MPH cluster :yes:

 

 

Thanks

[Knucklehead97]

I moved the hand of the gauge back to the bottom to see what it did. When I turned the key it slowly moved back past full. So I'm guessing it's deffinetely a ground problem. Started pouring down rain before I could diagnose the rest. Hopefully will find it tomorrow.