wacked fuel gauge
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Instructor
Joined: Apr 2004
Posts: 217
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From: Winnipeg MB
wacked fuel gauge
My fuel gauge seems to be working on my 87 but is way out of wack....by half a tank! It stays on full for ever and only goes down to 1/2 when it is nearly empty. Whats goin on? Any ideas?
Thanx
Thanx
Le Mans Master
Joined: May 2003
Posts: 5,362
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From: Delray Beach FL
I had the same problem on my 93. Had it at a dealership hoping that it was caused by bad gas from Shell (problem some in South Florida had.) Well, the sending unit was fine. It appeared that the CCM (Chassis Control Module) was starting to fail on mine. That with other work that needed to be done to it, I traded it in on a Z06. 
Hope you don't need to do anything as drastic. 
Hope you don't need to do anything as drastic.
Advanced
Joined: Jul 2004
Posts: 80
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I'm not sure which brand of gasoline you're using, but a major brand in Canada recently had problems with water and sludge in their tank bottoms at stations. The junk on the bottom of tanks makes certain sulfur compounds that attack the silver-palladium card on the fuel sending unit and leaves a blackish residue that will give false readings to the gauge; the swiping arm can't get through it. Some newer model cars use a platinum-palladium card that resists this attack (sulfur doesn't attack platinum). The unit can be pulled from the tank and cleaned with a solvent (methanol works best). On the other hand, it could be something else.
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Joined: Jul 2004
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The unit can be removed with relative ease. Fortunately, GM put the fuel pump/sending unit under the gas cap. The fuel tank filler door must be removed along with the cap and boot. Should you decide to do this, be careful not to rip the boot as age and gasoline spills are not kind to them. Wires, hoses and the unit will now be right in front of you. It's fairly straightforward from there - be careful not to tear the gasket under the 8 or 10 small screws, and carefully twist the unit as you remove it from the tank to clear the parts. Also, remember there will be a big hole in the top of the tank when you remove the unit, so try not to let any debris fall in there! And, you probably should disconnect the negative battery terminal, too since the GM manual calls for this no matter what the repair. I'd replace the fuel filter sock (strainer) while you're there. Good luck.
Race Director
Joined: Dec 2000
Posts: 17,551
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From: El Paso Texas
Originally Posted by Jinxie
My fuel gauge seems to be working on my 87 but is way out of wack....by half a tank! It stays on full for ever and only goes down to 1/2 when it is nearly empty. Whats goin on? Any ideas?
Thanx
Thanx
Yep. Your sending unit is going bad. Check the tech section for the repair. I can also email the article to you with pictures. I sent you an IM also.
