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

65-72 chevytoys · 05-06-2007, 10:10 AM

Anyone have their original stock fuel guage go all the way to the right way past full and stay there? The needle is stuck at 90 deg. What happend and what do I need to do to fix it?

bedsled71 · 05-06-2007, 01:05 PM

mine will do that and stay for a while then after i use alot of gas it goes down.,. never had it stay

65-72 chevytoys · 05-06-2007, 01:50 PM

What is causing it? It seems to be stuck at the 3 oclock position.

I know the tank is not overfilled the guauge was about 3/4 of a tank before it happend so I don't think it is a float problem.

Is the guage broken or a wiring issue?

Rupdog · 05-06-2007, 02:03 PM

i'm curious about this too. my truck has the same problem, and the tank was bone dry...

i added 5 gallons, and it didn't budge. the previous owner did the rear tank conversion, and i don't know what sender he's got in there.

the truck is still in the body shop, so i haven't had a chance to screw with it.

can someone chime in on this?

mnunn454 · 05-06-2007, 02:09 PM

It's got to be one of only a few possibilities:

Grounded or "open" wire going to the sending unit
Bad gauge
Sending unit grounded or open internally somewhere
Wrong sending unit for the gauge (should match re: ohms)
Stuck arm in the sending unit (up or down. I forget which) or sunken float.

I'd test all three areas (gauge, sending unit and wire connecting the two) with a digital voltmeter for grounds and opens.

Let us know what you find.

Ilike 72"s · 05-06-2007, 02:18 PM

I had that problem and found the wire gets damaged where it runs under the cover on your door rocker. It collects dirt, rust and grit that wears off the wire coating, causing it to ground out. Take the cover off, lift and wipe off the wire and watch your gauge. Worked for me.

Rupdog · 05-06-2007, 02:28 PM

i'll check those. thanks!

MT1972cheyenne · 05-06-2007, 02:51 PM

ILIKE72's is right on the money. An open circuit "or key off" will put the needle at or near 9 o'clock, and a grounded circuit will put the needle clear past full to near 3 o'clock.

va_tlc · 05-06-2007, 09:09 PM

mine was the sending unit. good luck finding one locally i called all 3 auto zone advance an fisher none could get it. but bill at atheys had it in stock i asked that same question a couple weeks ago and someone added a link to mine that has a awsome write up all about the gas tanks and sending units...troubleshooting it and how to check it, maybe someone can find it and link it here

northerngmc · 05-06-2007, 09:33 PM

An excellent tech/troubleshooting article on testing a fuel gauge.

http://www.6066gmcguy.org/Electrical-02.htm

I used it last month on my 69 GMC and it pointed right to the problem.

65-72 chevytoys · 05-06-2007, 09:52 PM

Lots of good info on that site. I added that one to the favorites.

northerngmc · 05-06-2007, 10:25 PM

But did you find the problem?

va_tlc · 05-07-2007, 06:00 AM

hey northern thanks alot for that site, it fixed mine right up, was hoping you would see this thread

EAST SIDE LOW LIFE · 05-07-2007, 11:31 AM

The same thing happened to me in my 50' and the 70.' In both cases it was the sending unit. THe conection @ the sender is weak because of it being corroded.

esll.

65-72 chevytoys · 05-27-2007, 09:54 PM

finally found the problem it was a break in the wiring from the sending unit behind the seat by the tank. My guage works now but that didn't help when I ran out of gas last weekend. Good thing I was close to home.

GREASEMONKEY72 · 05-27-2007, 10:24 PM

that used to happen to me cause the wire was just wrapped around the lead and it would lose connection, so i took the nut off that was there and put a connecter on the wire and srewed it back on with the nut and its been fine since

RyanG · 05-27-2007, 10:44 PM

Have the exact same issue.....replaced sending unit a while ago but that didn't fix it and then I just never got around to looking into it again. I just use a yard tick to see how much gas I have......will investigate further now that truck is in pieces.......lots of great help here....I love this site.

05-06-2007, 10:10 AM	#1
65-72 chevytoys Registered User Join Date: Dec 2006 Location: Wesley Chapel, Florida Posts: 1,113	fuel gauge problem Anyone have their original stock fuel guage go all the way to the right way past full and stay there? The needle is stuck at 90 deg. What happend and what do I need to do to fix it? __________________ 2004 Chevy Silverado 1500LS SWB 5.3L 2004 Corvette Z16 #770 Wish I had not sold 72 blazer

05-06-2007, 01:05 PM	#2
bedsled71 Registered User Join Date: Feb 2007 Location: yuma arizona Posts: 448	Re: fuel guage problem mine will do that and stay for a while then after i use alot of gas it goes down.,. never had it stay

05-06-2007, 01:50 PM	#3
65-72 chevytoys Registered User Join Date: Dec 2006 Location: Wesley Chapel, Florida Posts: 1,113	Re: fuel guage problem What is causing it? It seems to be stuck at the 3 oclock position. I know the tank is not overfilled the guauge was about 3/4 of a tank before it happend so I don't think it is a float problem. Is the guage broken or a wiring issue? __________________ 2004 Chevy Silverado 1500LS SWB 5.3L 2004 Corvette Z16 #770 Wish I had not sold 72 blazer Last edited by 65-72 chevytoys; 05-06-2007 at 01:52 PM.

05-06-2007, 02:03 PM	#4
Rupdog Registered User Join Date: Apr 2007 Location: Riverside, CA 92507 Posts: 129	Re: fuel guage problem i'm curious about this too. my truck has the same problem, and the tank was bone dry... i added 5 gallons, and it didn't budge. the previous owner did the rear tank conversion, and i don't know what sender he's got in there. the truck is still in the body shop, so i haven't had a chance to screw with it. can someone chime in on this? Attached Images

05-06-2007, 02:09 PM	#5
mnunn454 Registered User Join Date: Dec 2006 Location: Rhode Island Posts: 602	Re: fuel guage problem It's got to be one of only a few possibilities: Grounded or "open" wire going to the sending unit Bad gauge Sending unit grounded or open internally somewhere Wrong sending unit for the gauge (should match re: ohms) Stuck arm in the sending unit (up or down. I forget which) or sunken float. I'd test all three areas (gauge, sending unit and wire connecting the two) with a digital voltmeter for grounds and opens. Let us know what you find. __________________ 69 C-10 SWB Fleetside 454/TH400 (For Sale) http://67-72chevytrucks.com/vboard/c...ct=1299&cat=12 70 El Camino 454 TH700 29 Model A 4-DR Sedan Deluxe Last edited by mnunn454; 05-06-2007 at 02:10 PM.

05-06-2007, 02:18 PM	#6
Ilike 72"s Registered User Join Date: Jan 2007 Location: eastern oregon Posts: 623	Re: fuel guage problem I had that problem and found the wire gets damaged where it runs under the cover on your door rocker. It collects dirt, rust and grit that wears off the wire coating, causing it to ground out. Take the cover off, lift and wipe off the wire and watch your gauge. Worked for me.

05-06-2007, 02:28 PM	#7
Rupdog Registered User Join Date: Apr 2007 Location: Riverside, CA 92507 Posts: 129	Re: fuel guage problem i'll check those. thanks!

05-06-2007, 02:51 PM	#8
MT1972cheyenne Registered User Join Date: Dec 2006 Location: Montana Posts: 223	Re: fuel guage problem ILIKE72's is right on the money. An open circuit "or key off" will put the needle at or near 9 o'clock, and a grounded circuit will put the needle clear past full to near 3 o'clock.

05-06-2007, 09:09 PM	#9
va_tlc Registered User Join Date: Nov 2005 Location: VIRGINIA Posts: 905	Re: fuel guage problem mine was the sending unit. good luck finding one locally i called all 3 auto zone advance an fisher none could get it. but bill at atheys had it in stock i asked that same question a couple weeks ago and someone added a link to mine that has a awsome write up all about the gas tanks and sending units...troubleshooting it and how to check it, maybe someone can find it and link it here __________________ 1969 rs 1966fastback 1969swbc/10 2006gt 1972swb4x4

05-06-2007, 09:33 PM	#10
northerngmc Registered User Join Date: Jan 2004 Location: Whitehorse YK Canada Posts: 2,651	Re: fuel guage problem An excellent tech/troubleshooting article on testing a fuel gauge. http://www.6066gmcguy.org/Electrical-02.htm I used it last month on my 69 GMC and it pointed right to the problem. __________________ Blaine 59 GMC 9314 a.k.a. Whoopee 68 C20 50th Anniversary a.k.a. The Rat http://www.flickr.com/photos/northerngmc/ http://www.members.tripod.com/P-wee/index_032.htm 1.61803 is one H of a lot better than 3.14159, no really it is!

05-06-2007, 09:52 PM	#11
65-72 chevytoys Registered User Join Date: Dec 2006 Location: Wesley Chapel, Florida Posts: 1,113	Re: fuel guage problem Lots of good info on that site. I added that one to the favorites. __________________ 2004 Chevy Silverado 1500LS SWB 5.3L 2004 Corvette Z16 #770 Wish I had not sold 72 blazer

05-06-2007, 10:25 PM	#12
northerngmc Registered User Join Date: Jan 2004 Location: Whitehorse YK Canada Posts: 2,651	Re: fuel guage problem But did you find the problem? __________________ Blaine 59 GMC 9314 a.k.a. Whoopee 68 C20 50th Anniversary a.k.a. The Rat http://www.flickr.com/photos/northerngmc/ http://www.members.tripod.com/P-wee/index_032.htm 1.61803 is one H of a lot better than 3.14159, no really it is!

05-07-2007, 06:00 AM	#13
va_tlc Registered User Join Date: Nov 2005 Location: VIRGINIA Posts: 905	Re: fuel guage problem hey northern thanks alot for that site, it fixed mine right up, was hoping you would see this thread __________________ 1969 rs 1966fastback 1969swbc/10 2006gt 1972swb4x4

05-07-2007, 11:31 AM	#14
EAST SIDE LOW LIFE Senior Member Join Date: Mar 2007 Location: VANCOUVER ISLAND, B.C., Canada Posts: 1,602	Re: fuel guage problem The same thing happened to me in my 50' and the 70.' In both cases it was the sending unit. THe conection @ the sender is weak because of it being corroded. esll. __________________ Tomorrow is for doing today's stuff. ************************************* This truck has just the right amount of energy for me! Author: Warren Lake .... (member)

05-27-2007, 09:54 PM	#15
65-72 chevytoys Registered User Join Date: Dec 2006 Location: Wesley Chapel, Florida Posts: 1,113	Re: fuel guage problem finally found the problem it was a break in the wiring from the sending unit behind the seat by the tank. My guage works now but that didn't help when I ran out of gas last weekend. Good thing I was close to home. __________________ 2004 Chevy Silverado 1500LS SWB 5.3L 2004 Corvette Z16 #770 Wish I had not sold 72 blazer



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05-27-2007, 10:24 PM	#16
GREASEMONKEY72 Registered User Join Date: Aug 2006 Location: Bakersfield,CA Posts: 7,893	Re: fuel guage problem that used to happen to me cause the wire was just wrapped around the lead and it would lose connection, so i took the nut off that was there and put a connecter on the wire and srewed it back on with the nut and its been fine since __________________ -steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME

05-27-2007, 10:44 PM	#17
RyanG Registered User Join Date: Feb 2006 Location: Gilbert, Az Posts: 180	Re: fuel guage problem Have the exact same issue.....replaced sending unit a while ago but that didn't fix it and then I just never got around to looking into it again. I just use a yard tick to see how much gas I have......will investigate further now that truck is in pieces.......lots of great help here....I love this site.

Register or Log In To remove these advertisements.