fuel gauge question

[flobble]

My fuel guage stopped working a little while back. As I would drive along the guage would bounce from E to full and back and forth. When the truck was stopped the gusge would register somewhere inbetween and I didn't give it much thought, just assuming it was the fuel slossing around int he shallow tank. I replaced the sending unit with a new from from AB Linn, and the wiring is all new, but now the guage doesn't register at all. Checked the connections and everything's good. Before I buy a new guage, does anyone have any other ideas what the problem might be. I know it sounds obvious that it must be the guage, but when something's obvious is usually when logic flys right out the window. Is there a way to test the guage, or up to the guage to make sure everything else is good? Thanks for any help, I really appreciate it. On a happy note when I pulled up the inlet plate on the tank I realized I had 3/4 of a tank, good thing considering the price of gas! And yes, I always put Stabil in with the fuel in case I'm not driving for a while!

Paul

[TRACTORg25]

First thing I would check would be the instrumment panel ground. Check the fit between the panel and dash assembly for paint, rust or loose clips. Also check the back of the gauge make sure the bar is tight.

[tmbrwolf]

Momentarily ground the wire at the sending unit while someone watches the guage, do NOT hold the wire to ground very long, if the guage moves to full the wiring from the sender to the panel is good if the guage doesn't move there is a problen with the wire or guage or power at the guage the guage is grounded through the sender wire. if the guage moves then the sender is either bad or not grounded properly, don't assume that the sender is good just because you replaced it, I've put on many a defective part!

[g741]

You can do the necessary tests if you have an Ohm meter.

The fuel gage should show continuity between the two pins and from each pin to the gage body (ground). If you do not get continuity (no need to know what the values of the resistance should be, just that there is continuity) then the gage is not good. The little wires inside the gage on the coils is about as thick as a human hair and they do break, even on new units. The SW units are particularly bad. The AC gages seem to be a little better. The fuel sender should move from zero to 30 ohms from the pin to the gage mounting flange (ground) as you cycle it from full to empty. Then, if your gage is truly grounded to the truck when installed, and the fuel sender is grounded to the frame (sometimes a paint job will cause it to be isolated) and the wire from the tank to the gage is good, you should be in business. Sid

[kc8sfq]

I had a similar problem and found it to be bad ground of the tank. I ran a wire from one of the screws on the tank to the ground (mounting lug) for the tail light. Problem solved.