Ford F150 - gas gauge doesn't work.

All the gauges work other then the gas gauge. What would be causing it not to work. Could it be the float on the fuel pump isn't right anymore?

Thanks.

With a 1986 300cid I6, I doubt that you're fuel injected and most likely don't have a fuel pump in the tank. That being said, it is probably your fuel tank sending unit that is the problem and not the gauge. On my truck, (86 F150 SWB with 300 I6) it was a small hole that developed in the float. You'll need to drop the fuel tank, remove the sending unit, and check the float for holes. If it has a hole, replace and reinstall. If the float is okay, replace the sending unit and reinstall. Best to run the tank nearly empty before you do this. It really helps to have another set of hand reinstalling the tank. I didn't. Good luck.

Crawl under the truck, find the Y/Wh wire going to the top front of the fuel tank (just behind the rear axle) and ground it to the body or frame. Then turn the key to RUN and observe the gauge - if it heads for FULL, the level sender in the tank is bad. If not, the gauge or Y/Wh wire is bad.

Click my black Bronco in my sig & read thru the album named "90-96 Fuel Pump System" for info about dropping the tank, and "Fuel Pump Access" for info about NOT dropping the tank.

cool thanks I will have to try those.

It has a 1 barrel carb on it.

On a side note how big is the gas tank in these things. It looks huge.

Thanks

If it is a short wheelbase, the tank is 16 gal. If it is long bed, probably 19 gal. An optional tank behind the rear axle holds either 19 or 38 gal. I've got the SWB with the 16 gal tank, and get about 220 miles between fillups.

check the wire connections. The pins and sockets could be corroded. You can can have a good reading on one side of the connector and little to no reading on the other side. Use electrical cleaner to the clean the connector and dielectric grease to put it back together. 90% of all ectrical problems are corrosion