Fuel gauge issues

[Mailboxperry]

We'll I grounded the signal wire and the gauge slowly moved to full. It moved really slow. Took about 20 seconds to move all the way to full and about the same to empty when I removed ground. Is that normal? If so is it safe to say it's the sender installed wrong? Thanks.

[Mailboxperry]

I'm also assuming the other wire should be the power. If so how much power should be there?

Edited May 25, 2014 by Mailboxperry

[mopartechnician]

Its 5 volt if i remember right and I do belive the gauge should move just like it did

[Mailboxperry]

I don't think I have power there. Where could I find 5v on the truck to run a jumper wire to test it?

[mopartechnician]

12 volts will be fine for a test. Now if you dont have the 5 volt supply than you need to find where its bad. I will look at wiring diagram when I get a chance

[mopartechnician]

I

I was wrong there are only two wires used. A ground and a signal wire

Connector 129 is behind the drivers front wheel well.

Connector 130 is at the fuse box

Edited May 25, 2014 by mopartechnician

[Mailboxperry]

Bare with me here, so the non signal wire is a ground? Does that mean I just need to ground it and all should be good? Sorry I'm not the best with electrical but I will get it sooner or later.

Edited May 25, 2014 by Mailboxperry

[mopartechnician]

You need to ohm the ground wire at the connector to ground. You already know your signal wire works since you grounded it out and the gauge moved

And the black wire is ground

Edited May 25, 2014 by mopartechnician

[Mailboxperry]

So I was looking at the PCM and noticed its ground was pretty dirty. So to be cautious I unhooked the batteries before I removed the ground cable. Took it off and cleaned the ends. Hooked everything back up and now my fuel gauge is stuck on full. What did I do wrong or what does that mean?

[MnTom]

It means maybe your fuel tank is full? How much fuel do you think it has in it?

[Mailboxperry]

Lol. It's not full. I have about 150 miles on the tank.

[MnTom]

That still may be full according to the gauge. Give it some time and see what happens.

[Mailboxperry]

Thanks for your help.

[MnTom]

Thanks for your help.

You are certainly welcome, sir!

[Mailboxperry]

We'll it was short lived. Didn't even make it out of driveway and back to empty. Is it safe to say the PCM is to blame? All the wires are good. It also looks like the PCM has been replaced recently. It's the cleanest part under the hood and it's appears to be a Motorola brand.

[mopartechnician]

Double

Edited May 26, 2014 by mopartechnician

[mopartechnician]

Fuel gauge runs through the ecm on a diesel. Runs to the pcm on a gasser. I will find where it said that i dont understand why its this way

[mopartechnician]

This gauge is controlled by the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Powertrain Control Module (PCM) on vehicles equipped with a gasoline engine, or from the Engine Control Module (ECM) on vehicles equipped with a diesel engine over the Programmable

[Mailboxperry]

I am confused. I followed both wire from the sending unit and they go into the PCM. We'll I think it's the PCM, it's on the passenger side on the fire wall behind the air filter. Does it go to the ECM after the PCM?

[mopartechnician]

Thats what I don't understand, ecm controls all engine control stuff. The Pcm (on the firewall) controls everything else. But, the service manual states different, and I can only find the one wiring diagram with the wires running to the pcm. I would ohm out both wires and see what you get.