Fuel Gauge Not Working

[IvDogg]

Hi All,

I have a 99' XLT with 126k miles.

My fuel gauge seem to only work sometimes. It's not 100% consistent, but it usually work when I first start the car in the morning or night and shuts off shortly after.

My odometer was having the same problem, so I followed the common odometer fix mentioned in another post:

http://www.expeditionforum.com/f27/flickering-odometer-16847/

Not my odometer works perfect. I feel my fuel gauge problem is the same as the odometer problem was. Does anybody know what pin I should focus on in order to fix this similarly to fixing the odometer?

However, I could be wrong. Does anybody know a good way to isolate the problem from the circuit board to the sending unit?

Thanks!

 

[bedrck46]

I have not heard or read of any cures for a fuel gauge problem that would require a fix that is similar to the odometer. I could be wrong also. Maybe others will chime in about your issue. I would think that your problem is more of a connection problem rather that a problem with the instrument board. Re check your connections and also recheck the connector to the fuel pump assembly for any signs of corrosion or being loose. I know you don't have the same conditions on the roads where you are located as compared to us on the mainland salt snow etc but I also know that your roads out they do get a good deal of rain water and flooding. Lets us know what you find out. It also could be a problem with the float on the pump assembly.

 

[Yudaman]

I have a similar problem with the fuel gauge on my '98.
Only difference is, my gauge always shows empty! Anyone else having this problem?

But back to your problem, it could be a sending unit. Also, when starting the engine, do you make sure the ignition switch has returned completely to the on position? The Ford ignition can be picky about the spring return bringing it back to center. If it doesn't come back to center, then lots of goofy things happen.

 

[bedrck46]

the sending unit is basically a variable resistor I am trying to find the range of resistance will post it when I find it but you would be able to disconnect the sending unit and place a variable resistor in its place to at least check the gauge on the dash

 

[IvDogg]

Do you know if completely opening or closing the circuit will yield any results as to if the cluster is the problem or not?

the sending unit is basically a variable resistor I am trying to find the range of resistance will post it when I find it but you would be able to disconnect the sending unit and place a variable resistor in its place to at least check the gauge on the dash

 

[IvDogg]

I will check the connections sometime next week, I was planning on working on it this weekend but the football games look good!

I'm hoping it will be a simple electric/connection issue so I won't have to drop the tank.

I have not heard or read of any cures for a fuel gauge problem that would require a fix that is similar to the odometer. I could be wrong also. Maybe others will chime in about your issue. I would think that your problem is more of a connection problem rather that a problem with the instrument board. Re check your connections and also recheck the connector to the fuel pump assembly for any signs of corrosion or being loose. I know you don't have the same conditions on the roads where you are located as compared to us on the mainland salt snow etc but I also know that your roads out they do get a good deal of rain water and flooding. Lets us know what you find out. It also could be a problem with the float on the pump assembly.

 

[IvDogg]

Yes, verified the ignition position...

It does bounce up to the top after I start the engine (then leave ignition position to 'on') then it will either work for a little while or drop to empty.

I have a similar problem with the fuel gauge on my '98.
Only difference is, my gauge always shows empty! Anyone else having this problem?

But back to your problem, it could be a sending unit. Also, when starting the engine, do you make sure the ignition switch has returned completely to the on position? The Ford ignition can be picky about the spring return bringing it back to center. If it doesn't come back to center, then lots of goofy things happen.

 

[bedrck46]

Opening or closing may show something not totally sure I am still trying to find thr resistance of the fuel sender

 

[bedrck46]

Connect one lead of Instrument Gauge System Tester to the fuel pump assembly C415 Pin 2, Circuit 29 (YE/WH), harness side and the other lead of Instrument Gauge System Tester to the fuel pump assembly C415 Pin 3, Circuit 396 (BK/OG), harness side.

Set Instrument Gauge System Tester to 15 ohms.


NOTE: The fuel gauge should read below E (empty mark) when carrying out this test step.
Wait one minute and read the fuel gauge.


Set Instrument Gauge System Tester to 160 ohms.


NOTE: The fuel gauge should read F (full) or above when carrying out this test step.
Wait one minute and read the fuel gauge.


The above was taken from the service manual for a 99 model


you would need 3 resistors for this test
(1) 15-OHM SHOULD SHOW EMPTY
(2) 160-OHM SHOULD SHOW FULL
(3) APPROX 75-OHM SHOULD SHOW APPROX HALF FULL OR AS SOME MAY SAY HALF EMPTY

 

[IvDogg]

bedrck46,

Thanks for the detailed info I will give that a try but....

I don't have an instrument gauge cluster tester, I'm assuming if I buy some resistors from radio shack and connect them to some test leads I should get the same results?

Next, this should be done with the wire harness disconnected from the fuel pump and the ignition in the ON position?

Just want to make sure, thank you again.