Fuel Gauge

[StuntMan]

Well this fourth problem since my gear box fault last week . Which also suspect is electronic related. So now My fuel gauge had given up, and the low fuel light is on. Where is the location of the fuel sensor? I've tried resetting the Ecu but no difference at all.

 

[stamp11127]

Inside the gas tank. Not meaning to sound like a smart ass, check the fuel level before doing any work on the fuel level sensor. You can simulate the sender by varying the resistance level input to the gauge. Let us know if you want to try that first before changing out the pump/sender assy.

 

[tedennis]

Valid point above. I have many cars come into shop as a no start. Turns out they were just out of fuel.

Anyways, Fuel sender is in the tank with the pump. Most of them are only serviceable as the pump and sender assembly together. There are tests you can do to make sure it is not a gage issue. Without a wire diagram, I cannot tell you unfortunately. However I can tell you that if you locate the 2 wires that go to fuel level sensor that you can check the resistance. if the circuit is open then the sensor is bad. if you have a resistance reading, add a couple gallons of gas and the resistance should change. Again I cannot tell you if it will go up or down though. But it should change.

You can do both these test with it unplugged.

 

[StuntMan]

Inside the gas tank. Not meaning to sound like a smart ass, check the fuel level before doing any work on the fuel level sensor. You can simulate the sender by varying the resistance level input to the gauge. Let us know if you want to try that first before changing out the pump/sender assy.

Well what happend is the level was showing near just little above empty, and it was not accurate because the engine was about to cut out from a lack of fuel in the tank. I filled it with a full tank of gas and then the no fuel light came on and the gauge was dead. I would like to try and simulate the sender.

And the gauge seems to have reset itself and is now showing full tank of gas but I highly doubt it is the case

 

[stamp11127]

Wait for a while and see if the problem returns. You can use the trip meter to help gauge your fuel usage if you know what mpg's you were getting.

 

[Mikish]

I've had the same issue, dropped the tank 3 times testing the sending unit. Come to find out you can test the resistance in the harness. Lesson learned. Lol but still have dead fuel gauge. Is there a way tottest the gauge without scan tool or other specialty tools?

 

[stamp11127]

You can use a rheostat or resistors in place of the sending unit to provide the variable resistance in the circuit.

 

[Mikish]

The sending unit is sending proper resistance just didn't know if it was a fault in the ecm or the cluster itself.

 

[stamp11127]

Mikish in your case the next step would be to test the resistance at the end of the harness wherever it connects to. You would be looking for the same readings that you had at the sender. A slight difference wouldn't matter that much but a large difference would.

 

[Mikish]

Ok so I've replaced the cluster with a known good one. Still no fuel gauge. Anyone know where all the connections are so I can test the resistance

 

[StuntMan]

Quite interesting I put the gear selector in to "D" and try starting up and I get two different readings on fuel gauge. Also when ever I fill up the fuel gauge still goes to no fuel marking and no fuel light goes on.

 

[stamp11127]

The sender in the fuel tank which indicates the amount of fuel has a resistance range from 22.5(low) to 145(full) ohms. As long as you can simulate that resistance range you will be able to test the gauge.
Need to know the year of the Expy to determine the correct wire to use.

 

[StuntMan]

The sender in the fuel tank which indicates the amount of fuel has a resistance range from 22.5(low) to 145(full) ohms. As long as you can simulate that resistance range you will be able to test the gauge.
Need to know the year of the Expy to determine the correct wire to use.

It's a 1999 XLT 4.6 V8. Thanks

 

[ExplorerTom]

It appears mine just started doing this.

Drove to the airport to pick up wife and kids. Got 17.8 mpgs on the total trip (Scangauge). Dropped them off and filled up with gas on my way back to work. Low Fuel light was on, 0 miles to empty was showing. Pumped nearly 24 gallons. Drove 11 miles to work and just as I was about to park, I noticed the low fuel light was still on and gauge was still showing empty.

Also my trip mpg on my Scangauge didn't reset.

The gauge energizes when the ignition is cycled: goes from the "dead" position to an attempt at an "empty" reading.

 

[z168]

Ive had this problem for years. Mine only goes up half way. Low fuel light comes on when I drive over 350miles

Hi Stamp, how do you simulate the resistance? I can measure resistance with my multimeter but how do I create the 145ohm? Got any easy or practical suggestions?

 

[Bedrck47]

you can go to radio shack and by a variable resistor or fixed resistors. There is a connector at the tank or there is a connector under the tube for the intake snorkel

 

[Bedrck47]

print this is for a 2001 but the 2000 is the same

 

[Bedrck47]

you would want connector C-148 see attached print again its from a 2001 but 2000 is the same

 

[Bedrck47]

Place the resistor between pin #1 and pin #10 It is a square connector under the intake snorkel

You will also notice from the prints that the sensor circuit has nothing to do with the PCM

 

[Bedrck47]

The bad news is the sender isn't a part that can be purchased separately. It is part of the hanger assembly which also includes the fuel pump. If you have anything over 100000 miles on the expy then it would be best to replace the assembly. Make sure that you try to get the tank as close to empty as possible before dropping the tank