Gas Gauge Not Working

[Hikin Mike]

Car is a '68 Coronet 500 convertible. Car was stored in my garage for 11 years and just recently got it running. I drained the gas and put about 2-3 gallons. The gas gauge isn't working, it says it below empty. Figure it's a bad ground/connection.

Does the blue wire just pull off from the sender? I can move it side to side, but didn't seem to want to pull off. Didn't want to break anything so I left it alone.

Thanks.

 

[JimKueneman]

Car is a '68 Coronet 500 convertible. Car was stored in my garage for 11 years and just recently got it running. I drained the gas and put about 2-3 gallons. The gas gauge isn't working, it says it below empty. Figure it's a bad ground/connection.

Does the blue wire just pull off from the sender? I can move it side to side, but didn't seem to want to pull off. Didn't want to break anything so I left it alone.

Thanks.

Hi Mike,
Yes it does but it is a real pain to get disconnected. I personally would pull the trim panel off behind the emergency brake peddle in the car. There is a..... 8 pin connector.... I think that has the blue wire in it. Split that connection and then you can ground and open the blue wire to the dash to see if it works. You can also put an ohm meter to test the sending unit and ground. There should be a ground strap from one of the vent pipes that jump over the short rubber hose and clips to the metal vent tube that runs by the shock mount cross frame. It could be there is a bad ground if that is rusted or missing.

 

[Hikin Mike]

Hi Mike,
Yes it does but it is a real pain to get disconnected. I personally would pull the trim panel off behind the emergency brake peddle in the car. There is a..... 8 pin connector.... I think that has the blue wire in it. Split that connection and then you can ground and open the blue wire to the dash to see if it works. You can also put an ohm meter to test the sending unit and ground. There should be a ground strap from one of the vent pipes that jump over the short rubber hose and clips to the metal vent tube that runs by the shock mount cross frame. It could be there is a bad ground if that is rusted or missing.

Thanks Jim!

 

[JimKueneman]

Thanks Jim!

The wiring diagrams are also on the mymopar.com site I pointed you to.

 

[Ron H]

Was the gauge working before draining the tank? The blue wire is a pin connection but as mentioned is a B to get at. Agree, it more likely is a ground but if it wasn't working before could be the sending unit could be gunked up a bit though when this happens it's usually going to register where tank level was stuck there. If it was stored where mice could have been a problem trace the wire much as you can for any evidence of chewing (and other wiring). In my case I had poor ground connection in the dash and some deterioration of wiring in my fuse block I refurbished (but this was indicated by some other weird electrical things going on besides the fuel gauge). Cars that have sat have tendency of developing corroded G connections. Just tossing a few other tidbits out before the more involved deal of taking the unit out...

 

[91r/t]

Another thing to watch is the float. If your connections all look good and you can't get a response from the gauge check the float. I had my dusters gauge work in the fall when I put it away and in spring it wouldn't response at all. Sent the blue wire directly to ground and the gauge went to full. It ended up being a pinhole in the float and that sank to bottom of tank and wouldn't move with fuel level. Check the actual ground and gauge first like Jim said and if it responds it may be your float too.

 

[66Satellite47]

There is likely a ground strap on fuel line right near the tank. Make sure a good connection. I had a sender failure in the float/sender, broken wire on the reostat windings. Replaced the float assembly, problem solved.

 

[Hikin Mike]

Was the gauge working before draining the tank? The blue wire is a pin connection but as mentioned is a B to get at. Agree, it more likely is a ground but if it wasn't working before could be the sending unit could be gunked up a bit though when this happens it's usually going to register where tank level was stuck there. If it was stored where mice could have been a problem trace the wire much as you can for any evidence of chewing (and other wiring). In my case I had poor ground connection in the dash and some deterioration of wiring in my fuse block I refurbished (but this was indicated by some other weird electrical things going on besides the fuel gauge). Cars that have sat have tendency of developing corroded G connections. Just tossing a few other tidbits out before the more involved deal of taking the unit out...

Can't really say if it was working when I drained it. I only needed it to move out of the garage to remove a freezer, so I wasn't really looking at the gauge. I didn't remove the tank, just siphoned it out. I know it worked 11 years ago...lol!

 

[wagonman]

Hi Mike, read my thread Another Fuel Sender Rant. Lots of good info/help. My issue wound up being the sender. Good luck with these pesky problems.

 

[beanhead]

Before you get too crazy...try putting more like 9 or 10 gallons in and see what it reads. That should get you around the 1/2 mark if it's working

 

[Ron H]

as beanhead mentions if you know your ground isn't the issue was going to say put some gas in tank with some cleaner additive and drive it around if drivable or slosh the fuel around by pumping the car up and down and side to side could be unit is just gummy from sitting so long and that just could free it up otherwise before getting into deeper hassles

 

[Hikin Mike]

Before you get too crazy...try putting more like 9 or 10 gallons in and see what it reads. That should get you around the 1/2 mark if it's working

as beanhead mentions if you know your ground isn't the issue was going to say put some gas in tank with some cleaner additive and drive it around if drivable or slosh the fuel around by pumping the car up and down and side to side could be unit is just gummy from sitting so long and that just could free it up otherwise before getting into deeper hassles

Can't justify the expense. The car isn't going to be registered or insured any time soon so adding more gas just to sit doesn't make sense.

 

[Billccm]

StaBil is good for 5 years.

 

[Fran Blacker]

As bean said add more gas 2 or 3 gallons might not move the float.

 

[Hikin Mike]

UPDATE:

I pulled the kick panel by the e-brake pedal and disconnected the 8-pin connector. Grounded the blue wire to the gauge and didn't work. Measured the resistance from the plug to the sender and got about 32 ohms. Went under the tank and found the very corroded ground strap. As a quick test I used a jumper I have and grounded the fuel line to ground. Gauge moved. As best as I could I cleaned the corrosion from the ground strap and fuel lines. Re-attached and presto it works!

I have a bit more than a 1/4 tank.

Thanks to all for the help!