Last night I swapped out the windshield washer pump and now the fuel gauge reads empty... it worked right before I swapped it but not now. Can't figure out what gives...
Were you under the dash for anything lately? The clip that connects to the dash cluster is a long block, and one end of it can get loose and make several things in the gauge cluster misbehave. A small push back into place may fix this.
No but my foot sometimes hits the bottom of the dash when I take it off the brake (damn big feet). It is behaving like a loose connection, On the way to work it read full (which it is, just filled it up about 15 miles ago), on the way home after work it was reading a quarter tank and/or a hair under... I'll give that a shot if I can fit my hand up under there.
ok... it turns out the fuel gauge decides to read different levels every time I drive it, and occasionally it'll start at a higher level (~3/4) then gradually go down... I'm not sure what would be causing this kind of behavior... any suggestions? thank you.
If electrical troubleshooting doesn't immediately turn up something that is visually obvious, I usually turn to cleaning up ground connections as the next step. Sometimes a loose ground can be tightened. Sometimes I repainted something and made the ground worse ... ... sand a little paint back off and all is well again ... Most 40 year old cars can stand to benefit by cleaning up their ground connections. I don't know that this is a specific cause here, but it may be a contributing factor.
Hijacking the thread a little. If it's not the ground, wiring or the gauge. That leaves the sending unit. Where can you get a replacement. Tried to order one from Melvin's. Backordered for over 5 months. Will the one from a 71 mustang fit? From what I've read, there is only a small difference in the resistance readings, they are side mounted, and have the same connections. Hoping to install the new tank in the next couple of weeks.
3 possibilities. 1) Bad sending unit in the tank. 2) An open in the circuit (broken or disconnected wire) 3) Bad fuel gauge (this happened to me. Was easy to replace).
If all the above suggestions still do not solve the issue you may have a hole in your float on the sending unit. Mine fluctuated for a short time, then finally wouldn't move up from empty even with a full tank! I drained the tank, removed the sending unit and noticed the brass float was almost full of gas. It had a tiny like pinhole leak. I replaced the brass float with a replacement brass float and it works fine now I believe you can get the float in plastic? Or Brass. Not sure which one would last longer. Just wanted original style so used brass. Just a thought if all else fails
I found out my fuel sender has a two wire connector at the tank.. I tried redirecting the black wire to the chassis but that didn't do anything... don't know if they even make a unit for the '74+, I've only seen the earlier style with a different connector.
well it looks like my float is fine, does the fuel gauge wire run in the harness by the windshield wiper fluid reservoir? it worked proper on the way to work today but not on the way back... looks like a wiring issue.
Have you steel brushed the pin connections on the sending unit and traced the wires out? The connections and pins can get pretty badly oxidized and need cleaned. The wiring from/to the sending unit, on my Comet, go from the sender back along the body frame, to the left rear taillight. Then it goes from the rear taillight area inside the trunk left side, down under the carpet and goes under the kick panel side towards the front. You may have to trace it out though. Have you checked all the connections and ohm out the sending unit? There are many posts about checking, ohmning out and replacing sending units, gauges, in the forums. Just search Sending unit issues, gauge repair etc.... There are even wiring schematics in the tech sections, which were a great help for me. Gives you an opportunity to find out where everything is on your ride
I tried tracing the wire but once it went into/around the back seat I lost it, I found the other end of the harness by the front kick panel but the sending unit wire wasn't there... where does it come out up front? I'm pretty sure it's a wiring issue, once in a great while the gauge will move or work for a bit... I've checked the schematics, but it doesn't show wires in actual location in the car.
