C1 (1962) Fuel guage fluctuation

[Terry B.]

I've read the archives on related issues as well as other sources that lead me to believe that the phenomenon of my fuel guage climbing when I depress the brakes and/or turn on the headlights is due to a poorly grounded sending unit in the fuel tank. The ground for the sending unit has been checked out and is believed to be properly connected. Should I check again? Are there other areas to check that might be causing this problem? Is it possible that I'm creating fuel when I step on the brakes or turn on the lights ?

Thanks for any help.

[Doug F.]

Re: C1 (1962) Fuel guage fluctuation

i experimented a few years back, running a dedicated ground to the battery and as i recall, it didn't help, my guess is its a feedback thing, like your mechanic says, ' that's just the way it is, i use it as a reserve tank on my 61, when the needle gets down around E, just turn on the park lights and you get an extra 1/8 of a tank, but it also means you need fuel NOW !, i just built a 62 with all new harnesses and restored gauges and it does it too, i am sure that you can add something to the circuit that will eliminate it, but i don't know what it is, let's see if one of the guru's chime in

[Bob H.]

Re: C1 (1962) Fuel guage fluctuation

Terry

I had the same problem on my 62. The ground appeared ok. I even cleaned all the locations and still had the problem.

I finally ran an additional ground following the fuel line, hiding the wiring on top of the frame and grounded it to the screw grounding the right exhaust pipe. Solved the problem.

Bob

PS: I did run it directly to the battery first to see if it would work. When it did I then did the above.

[Larry B.]

Re: C1 (1962) Fuel guage fluctuation

Hi Bob, I am a little confused on how and where you ran the ground wire. Did you attach it to the actual fuel line then to a ground? Can you elaborate and attach a photo? I have also been fighting this ground problem for a long time. Thanks Larry

[Terry D.]

Re: C1 (1962) Fuel guage fluctuation

Larry
No you do not attach it to the fuel line, but you run it along the line to get down to the frame. A seperate ground line will solve most fuel gauge problems.
Terry

[Bruce B.]

Re: C1 (1962) Fuel guage fluctuation

Larry,
Very common problem.
As Terry mentioned run a separate ground wire from the fuel gauge sender ground post (on the gas gauge sending unit) down to the frame and attach the wire with a screw to the frame.
No more problems.

[Bob H.]

Re: C1 (1962) Fuel guage fluctuation

Hi Larry:

Terry is correct. I simply used a piece of wire (black preferred) and attached it to the same ground point on the top of the fuel guage. Make sure you clean up the spot. I just used a little steel wool.

Then I ran the wire down following the fuel supply line. Underneath, I looked for a ground point that I could use without drilling a new hole. I believe some guys just drill a new hole nearby but I didn't want to.

There is a small bolt that attaches the muffler/exhaust pipe ground wire to the frame. I ran my wire on top of the frame rail and over a couple feet and attached the wire to that ground point. I used connectors on both ends. You would be hard pressed to ever notice the wire.

The key is to simply make sure you have that good ground point.

Bob

PS: I also cleaned the ground point in the trunk. I believe this is near the lock and easy to see. You can always try cleaning that point first but the added ground wire is a sure fix.