'90 Bronco II fuel gauge does not work

[rangercat]

Recently my fuel gauge stopped working, reads totally empty even when full.
Is there another way other than removing the modular plug on top of the gas tank and shorting across the plug to see if everything from the plug to the gauge works?
Is there a 'usual suspect' at dash cluster (the gauge itself, a fusable link)
Got a Haynes shop manual, but I find no fuse listed for fuel gauge.
I really am not looking forward to dropping the gas tank and/or replacing sending unit and float
Feeling fuelish...if anyone can help me it would be much appreciated
Thanks

 

[martin]

The favorite culprit is a punctured float.

 

[BlackBII]

Yeah, remove the pump from the tank and see if the float is still floating. If the isn't floating, meaning it has sunk, then it's due for replacement.

The contacts on the sending unit itself can also wear out, but that is less common.

 

[Nathan123]

What causes the gauge to read way past full for 3/4 tank and then fly down to reading empty in around 20 miles?

 

[BlackBII]

What causes the gauge to read way past full for 3/4 tank and then fly down to reading empty in around 20 miles?

Contacts on the sending unit are worn out, and do not send a reading to the gauge once it gets to a certain level.

Example:

See all those gold horizontal lines? Each one sends a different level of resistance to the gauge. As the contact point moves across them, they wear out over time, notice how they are all worn down? That's probably what yours looks like from 3/4 way down.

 

[RobbieD]

Excellent explanation, and picture, BlackBII.

 

[Nathan123]

Thanks a lot that was a great explanation and picture. I just had the tank out of my BII to do the body mounts and patch the frame and the connector plug was all nasty and cracked and brittle. Changed that out and hoped it was that (it wasnt) but getting that tank down and out is more of a PITA than using the odometer. I was really hoping it was in the dash or a ground or somethin.

 

[xlt90]

ok, what if your gauge stays at quarter tank? I replaced the gauge pod and no change. think it's the sending unit or maybe a short?

 

[adsm08]

The favorite culprit is a punctured float.

That's what I was gonna say.

It was a poor design with a metal arm wrapped about 90% the way around a plastic float. You hit a bump wrong, it jumps, the arm pops the float, and you need to pull the tank.

Simple as that. Take the opportunity to make a removable patch panel for replacing fuel pumps.

 

[4.0B2]

That's what I was gonna say.

It was a poor design with a metal arm wrapped about 90% the way around a plastic float. You hit a bump wrong, it jumps, the arm pops the float, and you need to pull the tank.

Simple as that. Take the opportunity to make a removable patch panel for replacing fuel pumps.

this drove me crazy.. for about two months, i was so so so so confused.

 

[adsm08]

this drove me crazy.. for about two months, i was so so so so confused.

I dealt with it for 7 years before I got up the money and motivation to replace the pump.

I got it out and my g/f's father picked up the float (full of fuel and discolored by the dye) and thought it was brass until he started turning it in his hand to look at it and fuel ran out.

 

[4.0B2]

I dealt with it for 7 years before I got up the money and motivation to replace the pump.

I got it out and my g/f's father picked up the float (full of fuel and discolored by the dye) and thought it was brass until he started turning it in his hand to look at it and fuel ran out.

that's the only way i noticed it. when i turned the assembly upside down, gas started pouring out. my dad and i just look at each other and laughed...

 

[adsm08]

ok, what if your gauge stays at quarter tank? I replaced the gauge pod and no change. think it's the sending unit or maybe a short?

Sending unit. The gauges rarely go bad, its almost always the sender.

Fuel gauge accuracy (a joke, since between F and E it really is an idiot light) has become such an hot button for people that Ford has developed a service part for just the level indicator.