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Old July 19th, 2010, 08:11 AM
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JSoko JSoko is offline

 

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Location: Northwest Georgia
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I used to just keep the tank full and watch my milage

my first thought was a hole in the float, but your guage does work

several things to check
It will be a PITA but you may have a bad ground for the instrimunt cluster; dissasemble the cluster from the dash and check the ground connection remove it and clean it with steel wool or a pincel eraser; this might help

or; you can remove the bed and check the sending unit connections which can accumulate all kind of trash, dirt, moisture, and harbor corroision; pull the connector apart and clean it and spray it with WD 40 and put it back together this may fix it

The fuel gauge and fuel sending unit are very easy to test and in about 15 minutes you will know exactly what's wrong.

First thing you need to do is check all the fuses and make sure you are getting power to the gauge. If the other gauges are working, then you can safely assume power is coming into the cluster (red/yellow wire).Then check the black/yellow wire at the fuel tank connector and make sure you have a good ground.

If power and ground are good, then ground the yellow/white wire at the fuel tank connector. If the fuel gauge goes all the way to FULL, you have a bad sending unit. If it stays at Empty, you have a bad gauge or an open in the yellow/white wire.

Ford has a special tester for the Anti-Slosh module. But if you replace the fuel level sending unit and fuel gauge, and assuming the wiring is indeed good, then it's a pretty good bet the Anti-Slosh module is bad.


heres how you can test the gauge itself, with a multi-meter
With the sending unit float arm in the empty stop position, resistance should be 15 ohms (below E). With the sending unit float arm in the full-stop position, resistance should be 160 ohms (above F). The fuel gauge should read empty at 22.5 ohms and full at 145 ohms.

for the sending unit:
With ohmmeter positive lead on the signal wire lead and the negative lead on ground, check the resistance values of the fuel sending unit at various positions of the float arm. An open circuit will indicate infinity on the ohmmeter and a short will indicate zero ohms.

for a bad harness connector: check resistance from harness connector back to PCM. you"ll need a wiring diagram; which can be had in a Haynes or Chilton Manual

the bed isn't hard to take off, just get extra help so you don't scratch it

good luck as these type of problems can be an exstream PITA


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Last edited by JSoko; July 19th, 2010 at 03:54 PM.