help with fuel gauge - The 1947 - Present Chevrolet & GMC Truck Message Board Network

nitor · 11-30-2003, 06:36 PM

Hi,
I need some help with my fuel gauge. I just filled up my truck (70 gmc), the gauge says empty. I take the wire off of the sending unit, the gauge goes to full. Can anybody help me out with this?

Thanks.

nitor

Gordo · 11-30-2003, 06:57 PM

Assuming you disconnected the sending unit AT the sending unit it sounds like you need a new sending unit.

lukecp · 11-30-2003, 06:59 PM

Either the sending unit is binding, or it needs to be replaced. Remove it, put a voltmeter on the connection for the guage wire, and move the float up and down...the resistance should change as the float moves up and down.....30 ohms at empty, and 90 ohms at full if i remember correctly

nitor · 11-30-2003, 08:01 PM

Thanks for your help. I'll get another sending unit.

Jim

Olden Days · 11-30-2003, 08:28 PM

There is a chance that the sending unit is good but you have a sunk float. Happened to me. Took the sending unit out and discovered there was hole in the float. I have heard those brass floats are hard to find now but my parts guy dug me one up for 50 cents

nitor · 11-30-2003, 09:06 PM

Olden Days,

I'll pull the old one and check before I buy a new one. Thanks.

Jim

Longhorn Man · 12-01-2003, 02:32 AM

I've been told that a cork off a wine bottle makes a great flot...never tried it thoguh.

11-30-2003, 06:36 PM	#1
nitor Too many projects Join Date: Aug 2002 Location: Morrow, OH Posts: 344	help with fuel gauge Hi, I need some help with my fuel gauge. I just filled up my truck (70 gmc), the gauge says empty. I take the wire off of the sending unit, the gauge goes to full. Can anybody help me out with this? Thanks. nitor __________________ Jim '55 Chevrolet Pickup '56 Chevrolet Belair '04 Chevrolet Astro '95 Chevrolet Blazer

11-30-2003, 06:57 PM	#2
Gordo Registered User Join Date: Jan 2001 Location: Killingworth, CT. USA Posts: 3,378	Assuming you disconnected the sending unit AT the sending unit it sounds like you need a new sending unit. __________________ 1971 C10 swb stepside 350/700R4/3.73posi (retired as of 4/22/03) 1998 S10 short bed 2002 S10 Blazer 1942 Oldsmobile 1958 Massey Harris Pony 1951 Wife Killingworth, Connecticut May those who love us, love us, any of those who do not love us, may God turn their hearts. And if God is unable to turn their hearts, may he turn their ankles so we may know them by their limping. A man who works with his hands is a laborer; a man who works with his hands and his brain is a craftsman; but a man who works with his hands and his brain and his heart is an artist. Last edited by Gordo; 11-30-2003 at 07:00 PM.

11-30-2003, 06:59 PM	#3
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	Either the sending unit is binding, or it needs to be replaced. Remove it, put a voltmeter on the connection for the guage wire, and move the float up and down...the resistance should change as the float moves up and down.....30 ohms at empty, and 90 ohms at full if i remember correctly __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

11-30-2003, 08:01 PM	#4
nitor Too many projects Join Date: Aug 2002 Location: Morrow, OH Posts: 344	Thanks for your help. I'll get another sending unit. Jim __________________ Jim '55 Chevrolet Pickup '56 Chevrolet Belair '04 Chevrolet Astro '95 Chevrolet Blazer

11-30-2003, 09:06 PM	#6
nitor Too many projects Join Date: Aug 2002 Location: Morrow, OH Posts: 344	Olden Days, I'll pull the old one and check before I buy a new one. Thanks. Jim __________________ Jim '55 Chevrolet Pickup '56 Chevrolet Belair '04 Chevrolet Astro '95 Chevrolet Blazer

11-30-2003, 08:28 PM	#5
Olden Days Living In The Past Join Date: Nov 2003 Location: Rockies Posts: 709	There is a chance that the sending unit is good but you have a sunk float. Happened to me. Took the sending unit out and discovered there was hole in the float. I have heard those brass floats are hard to find now but my parts guy dug me one up for 50 cents

12-01-2003, 02:32 AM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	I've been told that a cork off a wine bottle makes a great flot...never tried it thoguh.



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