pogo69

my 69 rally fuel gauge is stuck in the full position and I didnt see a ground problem in the trunk? I'm not sure what causes this (gauge or sender or wire) anyone have a similar problem with a fix?

thanky

BackInTheGame

I have a similar problem, but no fix yet. In prep for my "refresh," I've already purchased a new tank sensor, but have yet to install it. I've heard that a short is the usual culprit. I am guessing that an open would cause it to always show empty? If no short at the tank, then somewhere along the wire, up to and including at the back of the gauge... Good luck! Please post your fix - I'll be working on mine this spring/summer.


In re-reading this, I think I have the OPEN VS. SHORT causes reversed?

oldcutlass

If you ground the wire at the tank it should read empty. If it does not your problem is between the sender and the gauge. If it does read empty when you ground it it's the sender.

frankr442

An open circuit will cause the gage to read full. Probably have a bad connection. Usually rusty ground screw or broken ground wire. A search will show much written about this.

jaunty75

As others have noted, this is caused by an open circuit, and it could be anywhere in the line between the gauge and the ground coming off the sending unit. One quick question: is the gauge actually stuck on Full, or is it actually well past full? Usually an open circuit will drive it well past full.

Your first task is to verify that it is not the gauge. Find the wiring in the trunk area again, pull it apart (there's usually connector connecting the end coming from the gauge to the end coming from the tank), and ground the end coming from the gauge with the ignition ON. The gauge should immediately go to E. If it does, there is no problem with either the gauge or the wiring from it to the rear of the car. If it doesn't, then maybe it's just that the needle is stuck.

If the gauge passes the test above, next is to get under the car and verify that the ground wire coming off the sending unit is properly connected and that the connection is clean and tight. It gets grimy under there after many years, and an open circuit here is a possibility. If the ground is ok, then you have to move to the sending unit itself, and getting at that may or may not require dropping the tank depending on the car.

pogo69

thanks for the reply... i'm pretty sure its not pegged past full so I will try grounding the gauge end of the wire and see what happens

pogo69

thanks for these replies...the gauge has been on the back burner (had brake issues) but i'm going to ground the harness gauge wire tomorrow and see if it goes to empty i did check the the ground and it was clean and tight

allyolds68

Excellent thread on it:

https://classicoldsmobile.com/forums...hats-next.html

Read Eric's (MDchanic) responses