Fuel gauge no realding after tank was cleaned and lined - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Kw69 · 01-29-2016, 01:36 PM

Hey guys,

Thinking caps on, ok had the fuel tank cleaned and lined from the shop. Put it all back together and my gauge does not work. Put a new sending unit in and still reads no fuel. Pulled the sending unit back out, held it in my hand touched the side of the tank and bingo it works the fuel gauge. U can then move the float and it works. Put it back into the tank and it goes to zero or no fuel....now it all works fine prior removing the tank. What gives? The wire is fine, both connections are good, what am I missing. Thanks in advance,
Kris

leuggy · 01-29-2016, 01:50 PM

need to make sure you have a good ground

Kw69 · 01-29-2016, 02:10 PM

The wire never appeared to have been grounded when I look at it. Is the wire supposed to be grounded in a certain location?
Thanks

davepl · 01-29-2016, 02:51 PM

No, the grey gauge wire measures resistance to ground. So it connects to the sensor, the sensor through the swing-arm potentiometer to the sender assembly, the sender assembly to the tank itself, and the tank itself to the ground.

So the whole sender assembly needs a solid connection to the tank, which it will have unless it's all full of sealer. And the tank needs a good ground to the body, which it normally has just through mounting.

Really sounds like the sender isn't making good connection to the tank itself from your description, but I'm unclear how that could happen so don't have a good suggestion, maybe others might...

**VetteVet** · 01-29-2016, 04:47 PM

If your gauge reads empty all the time then there are three possibilities.
1. The sending unit wire is grounded.
2. The float arm is not moving.
3. The tank is empty.

Take the wire off the sending unit and hold it away from any ground. The gauge should read way past full. with the key on.
Now touch it on the tank and see if the gauge reads empty. It should.

Next get a meter and check the ohms between the sending unit connection and the tank and the cab ground. if you read zero ohms the float arm is stuck down or there's fuel in the float or it's installed so that the float is hitting the tank body and can't move. Or there's no gas in the tank. Don't laugh it's been done.

01-29-2016, 01:36 PM	#1
Kw69 Registered User Join Date: Sep 2015 Location: Florida Posts: 111	Fuel gauge no realding after tank was cleaned and lined Hey guys, Thinking caps on, ok had the fuel tank cleaned and lined from the shop. Put it all back together and my gauge does not work. Put a new sending unit in and still reads no fuel. Pulled the sending unit back out, held it in my hand touched the side of the tank and bingo it works the fuel gauge. U can then move the float and it works. Put it back into the tank and it goes to zero or no fuel....now it all works fine prior removing the tank. What gives? The wire is fine, both connections are good, what am I missing. Thanks in advance, Kris __________________ 2009 GMC 2500HD 6.0, 6 speed auto, stealth grey, 4x4 Z71, Bilsteins, Black Bear Tuned. Pulls the 10k fifth wheel all so easy. 1969 CST 350 black long bed, 3 on the floor, PS, AC, drum brakes, old school and love it.

01-29-2016, 01:50 PM	#2
leuggy Registered User Join Date: May 2012 Location: moose jaw, sk Posts: 92	Re: Fuel gauge no realding after tank was cleaned and lined need to make sure you have a good ground

01-29-2016, 02:10 PM	#3
Kw69 Registered User Join Date: Sep 2015 Location: Florida Posts: 111	Re: Fuel gauge no realding after tank was cleaned and lined The wire never appeared to have been grounded when I look at it. Is the wire supposed to be grounded in a certain location? Thanks __________________ 2009 GMC 2500HD 6.0, 6 speed auto, stealth grey, 4x4 Z71, Bilsteins, Black Bear Tuned. Pulls the 10k fifth wheel all so easy. 1969 CST 350 black long bed, 3 on the floor, PS, AC, drum brakes, old school and love it.

01-29-2016, 02:51 PM	#4
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: Fuel gauge no realding after tank was cleaned and lined No, the grey gauge wire measures resistance to ground. So it connects to the sensor, the sensor through the swing-arm potentiometer to the sender assembly, the sender assembly to the tank itself, and the tank itself to the ground. So the whole sender assembly needs a solid connection to the tank, which it will have unless it's all full of sealer. And the tank needs a good ground to the body, which it normally has just through mounting. Really sounds like the sender isn't making good connection to the tank itself from your description, but I'm unclear how that could happen so don't have a good suggestion, maybe others might... __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

01-29-2016, 04:47 PM	#5
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,718	Re: Fuel gauge no realding after tank was cleaned and lined If your gauge reads empty all the time then there are three possibilities. 1. The sending unit wire is grounded. 2. The float arm is not moving. 3. The tank is empty. Take the wire off the sending unit and hold it away from any ground. The gauge should read way past full. with the key on. Now touch it on the tank and see if the gauge reads empty. It should. Next get a meter and check the ohms between the sending unit connection and the tank and the cab ground. if you read zero ohms the float arm is stuck down or there's fuel in the float or it's installed so that the float is hitting the tank body and can't move. Or there's no gas in the tank. Don't laugh it's been done. __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.



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