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Fuel gauge not working

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70sixpack

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Hello all.
It has been a while since I have been on the site, enjoying the summer with my car. I have a 70 GTX 440 6bbl and have a problem with the fuel gauge. It was working then every once in a while it did stopped for a few miles now it stopped all together. It is a new sender and I ran a ground to the sender which I read on here and the gauge pinned full. (Only did it for a few seconds.) I have tried grounding the sender with hose clamps on the fuel line but that did not work. The fuel lines are new and stainless. HELP please. I do not know what else to do..
 
Search around. Tons on this. Mine did not work, does not work, and will never work. Track the mileage. After 150 or so, get fuel.
 
Did you check the wire that runs from the dash, under the carpet, back to the tank? Mine had cracked under the back seat and the gauge quit any time somebody sat back there.
 
if you grounded the sender wire and the gauge worked,then most likely your sender is bad.just make sure you are getting good contact at the sender with the wire first.if you pull the sender it should read between 10 and 73 ohms when you move it by hand while hooked to a meter.
 
Yes temp gauge works fine. I replaced the sender thinking that was bad and it did not correct the issue. I plan on trying a different are on the frame for a ground. I did ground the sender wire from the dash and it pegged the needle to full. If I could only remember where I grounded it to?/
 
Always wondered why the factory didn't use a separate ground strap for the sending unit. I guess that 5 cent clip on the fuel line was good enuff at the time.
 
Yes temp gauge works fine. I replaced the sender thinking that was bad and it did not correct the issue. The new one did read from 10-70+. I did ground the sender wire from the dash and it pegged the needle to full. I have tried different areas for a ground still ng. Any ideas?
 
Trying to ground the sender on the MAIN fuel line will not work; the line is insulated from the sender by the rubber connecting hose. Your sender ground HAS to be on the actual sender. It can be on the circular sender plate itself or on the short fuel line that comes out of the sender.

There is a factory ground strap that grounds the sender's short fuel line to the main fuel line by bridging across the rubber hose connecting them. This depends on the main fuel line being grounded on the engine block via the fuel pump and its bolts. See here: http://www.gastanks.com/Mopar-Sending-Unit-Ground-Strap-3-3_4/productinfo/C-GS/

When you say the new sender measured 10 to 70+, do you mean ohms? Those numbers sound OK.

Also, disconnect the guage wire from the sender and turn the key to RUN, and use the voltmeter to measure the voltage coming out of the wire: it should vary on-off-on-off-..... between 12v and 0v. If your temp guagae reads correctly, then the voltage limiter in the dash appears to be OK.
 
nm9stheham said:
Trying to ground the sender on the MAIN fuel line will not work; the line is insulated from the sender by the rubber connecting hose. Your sender ground HAS to be on the actual sender. It can be on the circular sender plate itself or on the short fuel line that comes out of the sender.

There is a factory ground strap that grounds the sender's short fuel line to the main fuel line by bridging across the rubber hose connecting them. This depends on the main fuel line being grounded on the engine block via the fuel pump and its bolts. See here: http://www.gastanks.com/Mopar-Sending-Unit-Ground-Strap-3-3_4/productinfo/C-GS/

When you say the new sender measured 10 to 70+, do you mean ohms? Those numbers sound OK.

Also, disconnect the guage wire from the sender and turn the key to RUN, and use the voltmeter to measure the voltage coming out of the wire: it should vary on-off-on-off-..... between 12v and 0v. If your temp guagae reads correctly, then the voltage limiter in the dash appears to be OK.
Click to expand...

I have not had a chance to work on the car lately. Yes to your question 10-70 ohms. And yes there is voltage coming out of the sender wire. You mentioned to bridging the wire on the fuel lines that come out of the sender. Does it go from one fuel line to the other? Or just jumps over the rubber fuel line. Not sure how it should run since I had my delivered back to me after a few years from the restoration shop in boxes. Any pictures that show this ground strap? I have the original strap just want to run it correctly.
Thank you...

- - - Updated - - -

If it makes a difference my car is a v code...
 
Do you have your old sending unit? If so hook up a jumper wire from the connector at the tank and run it from out from under the car so you can test the float/unit also use a ground wire to the unit and look at the gauge at the same time. turn the key on and manually move the float 1/4 or so be patient as the gauge takes a few seconds to register. run the float full open full empty half way etc to see if the gauge is reading right or not. if the gauge does not read at all then check your wire if it is secure then that unit is bad. If it only reads a 1/4 and should be full then check the stops on the unit etc.
 
That little jumper clip goes from the metal fuel outlet tube on the tank, jumps paste the rubber hose and the other end goes to the fuel line running up towards the motor. If that's what your asking. Hopefully the metal fuel line is grounded to the frame/body of the car.
 
The best ground of the main fuel in that situation would be the main fuel line to the stock-type fuel pump and via the fuel pump body to the engine block. But that depends on the original hard-line fitting from the main fuel line to the pump. If there is an electric fuel pump and/or rubber fuel lines up near the engine, then that ground via the main fuel line will not work. (You can't count on the fuel line body clips to give a consistent ground.)

If you have any varaible in your main fuel line connection to a stock type fuel pump and block, then run the sender ground direct to chassis.

BTW... I absolutely don't know if the V code makes any difference.... but I would not think so.
 
The sending unit must be grounded at the edge of the unit opposite the rubber gasket, at the point where the unit wire to gauge mounts for best results.
 
Well here's the update. It works! It seems to be the ground on the fuel line was not working. I tested the wire to the sender from the dash and it was pulsating. I did this with a ground to one of the tail lights that I know is good. My fuel lines are brand new (1 year and 500 miles ago) stainless. Well when I worked on the contact with the little factory ground strap the gauge started working. It would had made life easier if I had more than 1-2 gallons of fuel in it that way the gauge would have been easier to see the reading. DUH
Thank you again for all your help!!!
 
Glad to hear it works, now go out and do some burnout videos :)
 
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