Junkyardjeff

When I know its not anywhere near that full so is it a gauge or sending unit problem,it does have a new aftermarket sending unit in it and I do not want to drop the tank again.

Pwaho

Is there a question here?

Why was the new aftermarket sending unit installed?

What it causing the same problem?

Junkyardjeff

It came with a new fuel pump and tank when I changed over to the 90 and up single pump fuel system,worked fine the last time I drove it and when it quits raining will check the grounds. Its my 88 bronco.

wde3477

Guess it depends on how much effort you're willing to put into this. Since the sending unit has been changed - yep, I'd start chasing the wiring and gauge. FWIW, remember the 70s vintage Chevy's with the big clock dial fuel gauges having a similar issue, as well as my own '89.

Would go way past full on fillup, stay there for about 100 miles, then drop from way-Full to quarter tank in the next 50 miles before being bone-dry empty with the needle one nudge of black space above 'E' - a rather inconvenient finding on the Interstate in the middle of nowhere.

Being the function-over-form type, just learned to deal with it - when the needle dropped, it was time to start thinking about fueling up.

Junkyardjeff

Chris_1

iTrader: (1)

All the way to full is a short to ground I believe. Sounds like a wire is shorted to ground somewhere most likely.

Junkyardjeff

I will check it out when I can get it in the garage,it worked for a couple minutes so its got a half tank.

mach1threat

Happened with my fathers truck since he owned his 1988 f150 when he bought used in 1991. The tank was Empty when it was actually showing 1/4. Tank. We just got used to it lol.

May want to pop the bed off and replace. Pump assembly if you develop any other problems. Maybe a ground too.

Junkyardjeff

I will look at it when it warms up and just put some gas in every time I drive it and watch the miles.