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Hope everyone is doing well. This all started when my old gauge started jumping back and forth and finally pegged way past FULL - actually almost pointing straight down. I am doing a partial restoration so I decided to go ahead and replace the key parts.
I installed a new sending unit and a new gauge. When I powered up - the fuel gauge pegged past FULL. I pulled the brown ohm wire from the sending unit and grounded it. The needle moved to EMPTY. So...what does that mean? What is my next step? I have read a couple of prior posts but I am not finding the answer.
I have some more info - I tested to see if I was getting an ohm reading at the connector for the gauge and I am. I also checked to see if I am getting 12v to the gauge and I am. When I turn the power on the gauge goes past the FULL mark to the 3:00 position and I lose the ohm reading.
Visit the Willcox technical site that will show step by step instructions to determine exactly where the problem lies.
I did that and have gone through all the steps. The ohms on the sending cable register at the plug for the gauge and then when I turn on the power the ohms zero out. Even tried a new ground from the sending unit to the frame. No dice.
I would try using a temporary piece of wire cable run from the sending unit to the gauge, that will indicate the wiring harness is not your problem. Use the same power source that is currently connected (OEM) to the gauge.
I would try using a temporary piece of wire cable run from the sending unit to the gauge, that will indicate the wiring harness is not your problem. Use the same power source that is currently connected (OEM) to the gauge.
Well did all that - I can get it to peg on empty or peg on full. I think I am surrendering on this one and going to have my mechanic fix it. Frustrating....saying goodbye to $200. Thanks for your help.
Well did all that - I can get it to peg on empty or peg on full. I think I am surrendering on this one and going to have my mechanic fix it. Frustrating....saying goodbye to $200. Thanks for your help.
Sounds like the sending unit is not moving, stuck, or broken. I don’t know if the gas tank has to be removed in order to inspect the sending unit. Did you try the temporary wire hookup with a new sending unit as it sits on the trunk?
.well...this is timely. I was adjusting my fuel level sender since I have the tank emptied. Everything is working fine, gauge is responding, I tweak the float, and get the gauge to indicate EMPTY when the float is fully down. So I go to install it and the ground wire connector separates from the lead. I fix the lead and solder on a new connector. Now everything is looking good so I install the sending unit in the tank and plug it in.
I come back up after installing it and turn the key on. NOW the gauge goes up and keeps creeping until it's over at the 3 o'clock position. What the heck? And now it is stuck over there.
I pull the sending unit back out and I exercise back forth full scale. Dang gauge is just stuck at 3 0'clock.
Just putting this out since I will continue troubleshooting tomorrow. Unless somebody has any new ideas. Meanwhile I'm going over to Willcox and see what I can find.
Ok.... looked at Willcox. I know what to do tomorrow. Don't feel so bad anymore. FYI. I must have removed the ohms wire with the key on. At least now I have a path to address this...... Thanks Willcox....
david71vette
Ok, I got mine working. There really wasn't anything wrong I just did not know the Willcox performance indications.
My gauge was stuck at the 3 0'clock position. No idea what I had done.
My sending unit was removed and I was willing to exercise the float, but since I can reach into the gas tank and do that I decided to just install it.
I installed my sending unit.
With the unit installed and the key in ON I installed the ground lead, and then the sensor lead. Nothing changed.
I then pulled the sensor lead.
Just to go in sequence I grounded the sensor lead.
I then plugged it back in the sensing stud.
I come up from under the car and the gauge reads Empty! Great! Now it has moved. (I did not know how to get off that 3 o'clock position).
I then exercised the float and the gauge tracks with the float change.
All good.
Last edited by carriljc; Apr 11, 2021 at 04:47 PM.
71 corvette fuel gauge problem
