Fuel Gauge Not Working

[sui_winbolo]

I have an '83 Grand Prix that had an engine swap last summer, (check out my gallery for pics), anyways before that the fuel gauge did not work. It always shows empty.

What do you guys think is the problem? The gauge or something else?

 

[srercrcr]

I've always had accuracy issues with mine, 1/4 tank off, but never just died (like my pickup did). I would suspect a bad sending unit in the tank, a ground for the gauge, and finally the gauge itself. You could get some used gauges on ebay, swap out the fuel gauge (very easy), that would eliminate one out of three.

 

[sui_winbolo]

I think we're going to bring it in to a mechanic to find out what exactly is the problem.

If it is the fuel sending unit, how much do they usually cost? My dad talked to a Pontiac parts dealership and they said it would cost about $270. But I was looking online, from what I see it should be more around $100.

Also does engine matter? Right now I have a Pontiac 301 v8 from a 1980 Trans Am.

 

[ONE EYE]

if your gauge moves to empty when the key is turned to power your gauge is fine, if it has power and its sitting on empty or lower its the power wire, if it pegs way past full then its the ground.

this is how all gauges except the tach can be troubleshot, if they are electrical.

hope this helps.

 

[sui_winbolo]

Alrighty, thanks for the information one eye.

I was talking to my dad, he said he thinks the gauge shows up 1/4 of a tank when full, I can't remember this because last time we filled it up was months ago, he could be right, but I'm not 100% myself. What would the problem be if this is the case?

Just trying to get all the bases cover to find out the source of the problem.

 

[srercrcr]

Keep in mind you can fill up every 150 miles to be safe.
The part would be something like $100. Either the dealer is charging a fortune for an AC Delco part or that includes labor.
The engine/carb do matter at least as far as GM specifies. They usually have different part numbers based on which engine and how many vapor return lines there are. I have a 78 GP 4bbl with the fuel line and two vapor lines.

 

[pontiacgp]

one eye gave you the way to check your gauge....and way is to if ground the wire that goes to the gas tank and your gauge goes to full then your gauge isn't the problem...you might just have a bad connection at the tank...remember the car is over 20 years old

 

[G_Body_Enthusiast]

hahaha funny story. every time it would rain my fuel gauge would stop working. it went like this for awhile and decided to fix it. for some reason it was the sending unit.

i replaced it and havent had a problem since. i would be inclined to think its of the sending unit since it has a float and it goes up and down up and down all the time and over 20+ years...yeah i could see it going back. grounds are possible but mine was perfect when i check it out. i've been inside my dash cleaning the clear plastic to my gauges and speedo and i know that was all kosher.

 

[sui_winbolo]

Wow, that's very strange, haha.

We brought it in couple weeks ago, it was the fuel sending unit. It cost like $160 to buy the part, not too shabby. They should have it done this week. They also installed my new door handle. The interior driver side handle just snapped in half one day.

But now I don't have to roll down my window, reach outside the car to get out! yay! haha.

 

[Esotericnem]

I'm having problems with my fuel gauge.....when the cars off, the needle goes a little bit below full, then when I start it, it goes past full.....I know oneeye said it can be grounding issues, where do I find the ground in a 81 Cutlass? Also my speedometer stopped working all of a sudden, please help!