fuel gauge problems

I think my fuel pump/sending unit may be on the way out. I have a 93 Bronco and the fuel gauge will go all kinds of crazy it will go from empty to full to way over full to anywhere in between while sitting still idling. Does this sound like its the sending unit in the pump? just want to make sure before I spend the money to replace the pump. Thanks in advance.

Sounds to me like your ground is going bad. Probably corrosion, like my did. Look from the sending unit for what I believe is a black wire. Make sure that is nice and clean and bolted to the chassis tightly. If it is good then check the fuel gauge wire, That is a yellow wire from the sending unit to the dash. Make sure there is no corrosion on that wire either. I had a similar problem with my gauge as well. My problem was corrosion on the fuel gauge wire. a quick cut and splice and it was good again. Let us know if that helped.

yo,

As NR Advised;

Ground Locations & Diagrams in 92-96; (pump and fuel level sender share connector C441 at tank)

G100 @ LH front of engine compartment on Driver's Side upper radiator support

Pic by Bill (subford)

&

G200, Instrument Cluster ground is inside passenger side kick panel

Pic by Bill (subford)

If good;

floats either way - There is a brass float attached to the sending unit & eventually they can develop a pin hole leak

Thanks for the info, I will check the grounds this weekend and if all checks out there I will drop the tank I guess and check the float and the sending unit contacts. I really hope its a ground so I dont have to drop this 33 gallon monster.

yo KEVIN,

I have the 96 Bronco WORKSHOP Manual Testing in my site @ http://www.broncolinks.com/index.php?index=921

Unfortunately

Same as your year

For Example;

A1 VERIFY POWER AT LOAD SIDE OF FUSE PANEL

Key to RUN.

Using Rotunda 88 Digital Multimeter 105-00053 or equivalent, verify system voltage at the load side of fuse

Key to RUN.

Using Rotunda 88 Digital Multimeter 105-00053 or equivalent, verify system voltage at the feed side of the fuse.

(they are checking for power and fuse condition of course, but also for a loose fuse or socket and so on. A loose fuse (internally and ext at contacts) has been known to occur due to prev owners or shops use of screwdrivers or pry bars to remove a fuse...lol; right! I have seen some use a flat blade screwdriver

Also see Testing & Connector Pin-Outs in 92-96 Bronco; Sender Range: Full = 160 Ohms; Empty = 16 Ohms;

http://www.supermotors.net/registry/media/744437

"... gauge that pegs past full indicates an open circuit (broken wire; unplugged connector; corroded terminal; burned sender) on the Y/W wire.

gauge that pegs past empty indicates a short to ground (pinched to the frame, body, or dash supports) on the Y/W wire, OR a sunk float.

gauge anywhere in between that doesn't move indicates an open circuit (blown fuse; corroded terminal) on the power (battery) side of the gauge OR a bad instrument cluster ground at C251 pin 9.

The terminals of C251 (& C250) are known to corrode & lose contact. Polish both the connector pins AND the film circuit pads with brown paper or a pink eraser. The larger version of C441(WPT454) was used until 93.

The level sender can usually be disassembled & repaired by bending the wiper arm inside the plastic housing to apply slightly more force..." by Steve83

The tank is not heavy IF you remove all the gas. Use a metal barbed fitting to carry the end of some cheap vinyl hose to the bottom of the tank and siphon the gas into gas cans. I have had mine out several times. If you take it out be sure to paint the tank where it contacts the skid plate, as they have a tendency to rust out there.

Hey Kevin the fuel pump access door mod on Miesk5 site works like a champ. use a grinder with a thin cutting disk take it slow and barely cut thru the metal. very simple job and makes pulling the fuel pump a 20 min job. I used a piece of 1/8 alluminum plate, silicone and some self tapping screws to cover the hole. Once the carpet is down cant tell its there. Oh yea the torch....not the tool for the job.You may see as i did on mine that the fuel sender unit has been rubbing (normal when fuel level changes) and has rubbed thru the contact strip there for not reading accurate check the grounds first tho.

I'd check the grounds, and otherwise would simply fill the tank, and note the odometer reading. Then every 200 miles fill the tank again. Dropping the tank can be a challenging experience, especially just for the fuel guage. I'd wait for the pump to fail. But that's just me. /emoticons/[email protected] 2x" width="20" height="20" />