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

mustanglx347 · 05-30-2004, 02:40 PM

the guage sits on full when the key is off, when you turn the key on, it goes past full into the 3 o'clock position. Oh, yeah, its an 82 4X4 blazer diesel conversion. Can anyone tell me how to fix this, is it the guage, sender, or a wire??????

All help is greatly appreciated.

blink32 · 05-30-2004, 06:55 PM

Well, is the gas tank full? If it is full then I would consider that normal to close to normal. Every 73-87 I've owned or driven always read past full when the tank was full. Not quite to the 3 o'clock position but past the full mark for sure. Now if your tank is not anywhere near full and it always reads that far past full check to make sure the power lead to the fuel sender is plugged in at the sender and/or there is power to the sender. When there's no power to the sender it will it will definetly report way over full (atleast on the gasoline models). Or the sender may be faulty.

79BIG10 · 05-30-2004, 10:33 PM

Check the ground at the tank itself. Sounds like a very common problem we have with these trucks.

dwjack · 05-31-2004, 08:41 AM

I have had this problem too. Once it turned out to be the sending unit on the tank. It has a ground wire that grounds to the frame and then goes through the sending unit to the float. My problem was that when I installed a new tank, the sending unit wasn't making a good connection for the ground to pass through. The other time it turned out to be the fuel tank selector switch. That time when the truck was cold it would go way past full, then later come back down.

mustanglx347 · 05-31-2004, 03:43 PM

thanks for the replies, the fuel tank is not full. when the key is off it reads in the full position, but when I turn the ignition on, itgoes past full into the 3 oclock position and stays there till i turn the key back off.

I am gonna check the wiring around the sending unit right after I replace the starter today.

thanks again for the replies, and hopefully i will have pics up tonight of the progress I have made since i got the blazer on Friday.

DrMaserati · 05-31-2004, 04:55 PM

It's a classic example of a ground problem somewhere in the circuit. With an open ground, the gauge will go as far as it can in the full direction.

JP

05-30-2004, 02:40 PM	#1
mustanglx347 Registered User Join Date: May 2004 Location: Texas Posts: 44	fuel gauge question, help the guage sits on full when the key is off, when you turn the key on, it goes past full into the 3 o'clock position. Oh, yeah, its an 82 4X4 blazer diesel conversion. Can anyone tell me how to fix this, is it the guage, sender, or a wire?????? All help is greatly appreciated. __________________ '71 Chevy stepside '50 Chevy 5 window '82 K5 Blazer '90 Mustang-stroked and sprayed '95 Nissan 300 ZX '04 Jeep Grand Cherokee

05-30-2004, 10:33 PM	#3
79BIG10 I'm back with 2nd truck! Join Date: Feb 2002 Location: Texas Posts: 3,775	Check the ground at the tank itself. Sounds like a very common problem we have with these trucks. __________________ 1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson

05-31-2004, 08:41 AM	#4
dwjack Registered User Join Date: Sep 2003 Location: Alaska Posts: 35	I have had this problem too. Once it turned out to be the sending unit on the tank. It has a ground wire that grounds to the frame and then goes through the sending unit to the float. My problem was that when I installed a new tank, the sending unit wasn't making a good connection for the ground to pass through. The other time it turned out to be the fuel tank selector switch. That time when the truck was cold it would go way past full, then later come back down. __________________ 1984 Silverado C10 GM Goodwrench 350 Edelbrock Intake/Carb Hedman Hedders 700R4 Transmission 12 Bolt out of an 81 275/60/15 Centerlines

05-31-2004, 03:43 PM	#5
mustanglx347 Registered User Join Date: May 2004 Location: Texas Posts: 44	thanks for the replies, the fuel tank is not full. when the key is off it reads in the full position, but when I turn the ignition on, itgoes past full into the 3 oclock position and stays there till i turn the key back off. I am gonna check the wiring around the sending unit right after I replace the starter today. thanks again for the replies, and hopefully i will have pics up tonight of the progress I have made since i got the blazer on Friday. __________________ '71 Chevy stepside '50 Chevy 5 window '82 K5 Blazer '90 Mustang-stroked and sprayed '95 Nissan 300 ZX '04 Jeep Grand Cherokee

05-31-2004, 04:55 PM	#6
DrMaserati Village Curmudgeon Join Date: May 2003 Location: Salem, OR Posts: 75	It's a classic example of a ground problem somewhere in the circuit. With an open ground, the gauge will go as far as it can in the full direction. JP __________________ 78 Chevy K30 duallie, 454, TH400 78 IH Scout II, 4X4, 345, 727TF 76 IH Scout II, 4X4, 345, 727TF 65 IH 1200C pickup, 4X4, 345, 4 spd 48 IH KB-8-F, RD-450, 5 spd, 35,000 GVW (a REAL truck) "Life is too short to drink cheap beer." Harry S. Truman

05-30-2004, 06:55 PM	#2
blink32 Registered User Join Date: Dec 2003 Location: OTR Posts: 338	Well, is the gas tank full? If it is full then I would consider that normal to close to normal. Every 73-87 I've owned or driven always read past full when the tank was full. Not quite to the 3 o'clock position but past the full mark for sure. Now if your tank is not anywhere near full and it always reads that far past full check to make sure the power lead to the fuel sender is plugged in at the sender and/or there is power to the sender. When there's no power to the sender it will it will definetly report way over full (atleast on the gasoline models). Or the sender may be faulty.



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