Mark IV fuel gauge question

[Shelly Harris]

I posted this on the Lincoln forum, but I'll ask here also....

Fuel gauge Working fine for my first 500 miles, now...
My tank is full but the gauge only reads 1/4 and the low level light is on.
As the tank emptys the gauge stays at 1/4 with the light, but then moves down to empty as I use up the last 1/4 tank.
Is this a faulty sender or gauge or what?
Also this started about the time I removed the INstrument panel to replace a few instrument lights.... It's a bitch to remove...do you think I damagesd something then? Thanks for any help

[Barry Wolk]

I hope you get a good answer, because mine is doing something similar on my '77 TC.

The sending unit uses a chassis ground. You could check there. You can also check to see if the gauge works by shorting the gauge lead to ground at the gas tank. Effectively, you're bypassing the variable resistor in the sending unit.

If you need to, changing the sending unit is relatively simple and can be done in the car. You remove the gas line, unplug the wiring harness, using a flat bar, rotate the collar to unlock the sender from the tank.

If it's stuck or rusty you can bend the three tabs up slightly to release the device.

I have my '77 sending unit out if you'd like a picture of it.

[Nick DeSpirito]

The gauge on my '76 Mark IV works fine, however when gassing up, I have to feed the fuel in slow or else the nozzle keeps clicking off. This started years ago, when I had a new fuel tank installed. My guess is that I have a kinked vent hose?

I've also recently been having this problem with the Mark II. The fuel seems to back up in the filler tube and I have to pull the nozzle out and wait for the fuel to drain out of the filler tube into the tank and then proceed again squeezing the trigger on the nozzle very slowly. It's become a real PITA to gas up.

[Shelly Harris]

Thanks Barry.... With that info I will check further, but not for a few more days as I'm driving the car in for its new vinyl top this evening.

Nick... same experience with the Mark IV which has a 25 gal tank. When filling up the fuel starts backing up the fill tube after 14-15 gals and shuts off the nozzle, so I have to finish the fill at half setting. No problem with the Mark II though.

[continentalguy]

Shelly,

I hate to admit this but when you turn these Mark IVs on the gas gauge goes down fast LOL :( Not only that but me and my dad have noticed the gas gauge moves faster than the speedometer:eek:.

[Roger Zimmermann]

Shelly,

...but me and my dad have noticed the gas gauge moves faster than the speedometer
But not in the same direction!