ok, as many know my fuel guage is stuck on full, and has been for a long time......well i think my fuel pump is about to crap the bed in the maxima, so i need the truck 100%....

So heres what ive done today.

-Took out the cluster face, (so i could touch the guages.) Took out the fuel guage itself from the cluster. I inspected it (didnt remove needle) and it looks new....i moved the needle and could feel it was still on the spring.

So i put the guage back in, and i moved the needle to empty (i have about 7 gallons in tank right now) i turned on the truck and the needle slowly moved back to the full position. (same speed it would as if you just filled the tank.)

While it was running i moved the guage back to E, and it slowly went back to same spot.....so i pushed it past Full, and it slowly came backwards back to same position its been stuck on.

Then i busted out the ol' haynes manuel, and looked at the wiring diagrams. I went to 12-38 Diagram 3 of 13. You see the wiring for the level. From the cluster its a Dark Blue wire, which i have located. during its way to the fuel pump it goes to a Dark Blue/Orange wire, which i have varified in the connector.

Now should the above have power? with truck on i have no power from my power probe. but the needle will move if i move it. Still no power while needle moves. (checking power at cluster, and varified i had a good ground because i tested a different wire and it lit up.)

Then the diagram shows the ground as a Black/White wire, which i have found, but it shows the ground end up near the PCM...So another dumb question, is it grounded at the PCM?

Also would the problem i explained seem like a wiring problem to you or do you think its my pump sending unit?

Last can i test the ground by grounding my probe to the wire and testing to see if others have power, so i can varify its a clean ground?




sorry for the novel...

 

Can you post up the wiring diagram? All I have is the 01 diagrams, and I suspect they are different than the 97 and earlier models.....

 

 

Cool.

Ok, looks like power goes to the gauge first, and from there to a variable resistor in the sending unit, then to ground. So, the fuel gauge is basically just a voltmeter.

Question now becomes: Which way does it go? Does resistance go up or down as fuel level goes up?

Try this:

Disconnect the harness from the fuel tank. Turn the ignition on, see what the gauge reads. Then, ground the wire that comes from the fuel gauge, and see what the gauge reads. It should be either pegged, or bottomed when NOT grounded, and the opposite when it IS grounded. If not, you have a wiring, or gauge problem, if it does, sending unit is the issue.

 

so ground the Blue wire from the cluster?

 

Correct.

 

Had the same issue myself, drove me nuts for weeks. After going through all the wiring, twice, I found that the float was stuck in the up position....kind of wedged against the side of the tank.

Believe it happened as my gas was probably sloshing around bigtime when I was bucking some huge snow piles with the plow. It was right after that I realized the gauge wasn't dropping.

Finally had to loosen the pump assembly lockring on top the tank, turned the unit about an inch and.....SPLOOOSH.... heard the float drop down and wallaah...worked perfect since.

Something to check if your wiring and gauge spec out.

^

 

i could understand why it could be the floater because i was off-roading with some buddies, found a dirt road straightaway, and i was going about 60-65 when i hit a dip, and (i think) the tires came off the ground.......since then no fuel guage....... and i had a full tank while this happened, and its stuck on full.

but thanks for that tip, im trying to eliminate wiring or the guage before having to drop the tank, but because you said that, makes me want to go and try that after work....

thanks....


and HEYYOU, I didnt have a chance to do your trick....started snowing again pretty hard, and i wasnt going to freeze my glutius maximus off to check it.....so ill be trying this method as well.