Contour Enthusiasts Group Archives Forums General Troubleshooting Fuel Gauge

The other day, my car unexpectedly sputtered to a stop. The fuel gauge showed nearly half a tank and the low fuel light never came on before it happened, but as it turned out, I really had run out of gas. From looking through similar threads I get the idea that the sensor that determines the gauge position and the one that turns on the light are independent. First of all, can someone confirm this? If it's true, it's interesting that neither one seemed to be functioning.

Once I filled it up, the needle went to Full but it barely moves below that position. Right now I'm just going by mileage with knowing when to fill my tank, but I'd like to fix this somehow. It seems to me that if there are two independent sensors, then it probably isnt just that the float is stuck.

Just wondering if anyone can give me an answer on this one, or if there's something else I should be looking at. Thanks.

There's only one sensor. It is located in the tank on the fuel pump module.

That signal goes to the electronics module in the instrument cluster. That module then operates the light and the guage.

Steve

I don't know what the newer tours have in the way of a low fuel sensor. A previous car I had used a contact mounted on the same float sender/fuel pump array in the tank. When it touched it the light on the dash came on for "low fuel."
I would pull the tank unit first and play with it to see if the gas gauge moves. Put an ohm meter on the pins and see if it changes when you move the float. Maybe something is hanging it up. Easier and cheaper than pulling the dash apart and buying a gauge. Swap the fuel pump while you are in there. Some of the parts stores sell the whole unit for not much more than the pump. Hopefully someone else with the same year that had their pump out will remember the sender and know if it has a separate contact for the low fuel. If it does then something is stopping the float from dropping.

It's weird though, the needle does move, it just indicates much more fuel than is really in there. For example, when it's full, it's slightly past the F, but when its totally empty, its somewhere between 1/4th and 1/2.

How difficult is it to get to the fuel pump/float assembly? How is the back seat connected, is it bolted or something?

It almost sounds like a bad gauge. There are some posts on how to change the fuel pump or it's in the FAQ?

That how-to doesnt explain how to remove the back seat, this is my first problem.

Also, is it in any way possible to move the float around to measure the sensor output without pulling the fuel pump out of the tank? There's a seal around it that I don't think is reusable, and I'd rather not have to replace it.

The seat is clipped in. Just pull up on it. The clips are junk so they may break. Mine used to squeek until I wrapped tape around the metal. The pump/sender come out as a unit. Don't try this project if you have problems with pumbing because the fuel lines are in tight and must be returned to their secure state or the car will go boom!

Is there any way to test the gauge?

I mean, of course, without pulling the fuel pump and manually moving the float...

If you can get the resistance specs from somewhere you can test it at the connector. If someone out there has an sender setting in the garage they can get resistance readings from it . Your next stop is the electronics parts store. Unless you know of a parts store that will let you borrow one to plug into your system at the tank.

I'll check my service manual today to see if it has resistance specs for the sender and voltage input specs for the gauge. If not, I guess I'm out of luck.

Also, I'm not sure how to artificially regulate the voltage to test the gauge. The sender is easy, just use an ohmmeter, but how can i rig something up to send a variable (and measurable) voltage through the gauge to test it?