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Fuel gauge calibration

New User
Posts: 2
Joined: 11/11
Posted: 11/23/11 10:14 AM

I just calibrated my fuel gauge which always was at 3/4 when full and past E with fuel still in tank. I read in my shop manual for my car and found the testing of the gauge which is fairly simple. 10ohm when full and 70ohm empty. Purchased resistors from radio shack. I did the sending unit test with float and different sending units with the same reading on the gauge. I hooked up the 10ohm resistor in series to ground and it gave the same reading as the sending unit 3/4. Now comes the fun part calibrating the gauge two holes in back of fuel gauge one for zeroing the gauge and the other to adjust to full this is done with power on with the resistors in series to ground. I used a T15 bit driver or a small straight screwdriver the same as the one you can keep in your shirt pocket.  

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Posts: 146
Joined: 10/09
Posted: 11/24/11 04:19 AM

please verify the wiring and the instrument cluster voltage regulator is working properly with a sometimes easy test..

unplug the sending unit at the tank....  turn the key on...   the gauge should swing all the way in one direction...

short the wire you have removed to ground.. turn the key on..   the gauge should swing all the way to the other side..

this verifies the gauge and the wiring is working properly.. not that its within calibration..  but that it is capable of full scale either direction..

see how the sending unit it grounded...  either through the tank.. or via a wire to an under body panel..  so.. figure that out.. set your digital OHM meter to 200 OHM scale and go to it..  

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