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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: ian75c10 on March 02, 2015, 11:42:02 am

Title: fuel gauge way past full
Post by: ian75c10 on March 02, 2015, 11:42:02 am

Hey guys so my fuel gauge has always read way past full when I fill the tank. It seemed as low as I could run the truck would be right when it hits E on the dot it would run out. Well the other day I ran out of gas at an 8th of a tank. Or even more that that according to the gauge. It way right between a quarter tank and empty when it ran out. Is there a quick fix in the dash that I can reset the gauge? I dont have any glass/plastic on my cluster over the gauges so I can actually touch the needle. I tried spinning it counter clockwise to read more accurate but it just goes back being too advanced. Is this something I need to get into the tank for? I have a carter 4070 fuel pump mounted under the tank on the frame rail. does this pump need more gas pressure from gravity because its more of a pusher than a puller? Thanks for the info in advance.

Title: Re: fuel gauge way past full
Post by: zieg85 on March 02, 2015, 12:14:40 pm

Full being at 3:00 is usually a bad ground but still having it go down might mean a resistor going bad on the back of the fuel gauge.

Title: Re: fuel gauge way past full
Post by: ian75c10 on March 02, 2015, 12:17:34 pm

Thanks, is the resistor something the autoparts might have and is it easily replaceable?

Title: Re: fuel gauge way past full
Post by: zieg85 on March 02, 2015, 12:22:04 pm

Quote from: ian75c10 on March 02, 2015, 12:17:34 pm

Thanks, is the resistor something the autoparts might have and is it easily replaceable?

Don't know, search the forum here I know it has been discussed in a thread not to long ago

Title: Re: fuel gauge way past full
Post by: rich weyand on March 02, 2015, 01:19:36 pm

Usually the gauge will read 1/4 at full and go down from there if the resistor is broken.
http://forum.73-87chevytrucks.com/smforum/index.php?topic=27370.msg227687#msg227687

Title: Re: fuel gauge way past full
Post by: ian75c10 on March 02, 2015, 05:18:07 pm

I just took the whole cluster apart and cleaned the contact point for the fuel gauge, they did look old. I couldnt find the ground wire for not only the fuel gauge but the entire cluster. Put everything back together and still reading same fuel level.

Title: Re: fuel gauge way past full
Post by: 76K20 on March 03, 2015, 02:05:33 pm

I think they mean the ground at the fuel tank.

Title: Re: fuel gauge way past full
Post by: enaberif on March 03, 2015, 02:38:49 pm

Quote from: 76K20 on March 03, 2015, 02:05:33 pm

I think they mean the ground at the fuel tank.

Yes it gets corroded or falls apart. Unfortunately you gotta drop the tanks to get to it most times.

Title: Re: fuel gauge way past full
Post by: 76K20 on March 03, 2015, 02:46:25 pm

Quote from: enaberif on March 03, 2015, 02:38:49 pm

Quote from: 76K20 on March 03, 2015, 02:05:33 pm

I think they mean the ground at the fuel tank.

Yes it gets corroded or falls apart. Unfortunately you gotta drop the tanks to get to it most times.

Or remove the bed

Title: Re: fuel gauge way past full
Post by: FlatBlack77 on March 03, 2015, 10:33:20 pm

my 79 does almost the exact same thing.

a full tank is like 2-2:30 on the gauge and empty is 1/8th.

and on my 77, full is full and empty is 1/8th. learned that the hard way.