Fuel level sender shot

[kkrover]

Fianlly got my 95 3.9 RRC running great and was driving down a cobblestone street today and the fuel level just dropped below empty and the light came one. I had a 1/4 tank at the time, filled it up to confirm amount of gas in tank and indicator is still dead an dlow fuel light is on.
Any ideas on what could have been jarred loose and where should I begin?

[LANDY96]

DAMN, mine just did that a few days ago too!!! It did however pop back, but it still doesn't seem to be accurate. I don't know if it is a loose wire, or the sender is dying?

[stevo-II]

Well crap, I have looked everywhere on my computer, but I had a bunch of pics of my sending unit/pump when I pulled it last fall and fixed it, but I can't find them.

Anyways, long story short, my sending unit was completely dead, I pulled the pump/sender to see if anything was obviously broken, and yeap it was. There was a copper wire that was soldered to the wiper and originally ran from the wiper to a small junction where it connected to the sending unit wire going out of the top of the unit. The wire was extremely brittle and had broken some time back (the gauge had not worked for several years before I bought the truck. The wire was fairly thin and no insulation - probably 16 guage stranded is what it looked like - it flexes as the float moves the wiper. I drained and dried the whole unit, removed the remaining ends of the wire nubs from the wiper and terminal connection by unsoldering them, then soldered on a new wire - I left the insulation on it, that might be a mistake cause I fear it might break down in the gas, but it should get caught in the strainer before it gets into the pump. Leave some slack in the wire so it can move. My gauge works fairly well now, the wiper still has some "dead spots" - I tried to clean it up with a pencil erasure - didn't seem to help much and mine does not go all the way to F when full, but it works on the low end and thats whats important. I used rosin core solder - not sure, seems like somebody said not to use acid core for things in the gas tank like fuel pumps.

So you might get lucky and this is all it is, just BE CAREFUL when dealing with anything in the gas tank. And for Gods sake, don't use a butane soldering.iron....LOL

Steve

EDIT: I found this pic and tried to highlight where the wire was broken.

[LANDY96]

Looks like good info! When it warms up a bit, I will open it up and take a look-see!

[kkrover]

The rave manual say to depressurize the fuel system before removing. Is this necessary and if so, anything i should be aware of, prepared for when I do it? The manual is a bit vague. When done, do you just reconnect everything and turn her on?

[stevo-II]

Yes, I opened the access hatch in the floor of the rear cargo area (hopefully your year model has that hatch) - disconnect power to the pump at the pump, then crank the truck for 10-20 seconds to depressurize the system. Then you can disconnect the fuel lines from the pump - might want to clean out that area first, mine had a lot of dirt. Please be careful from this point on - the retaining ring might be hard to remove, if you plan to use a hammer/punch to loosen it, find a brass punch to avoid sparks. Also, before you do all of this, check the electrical connections on top of the pump and the ground connection on the pump - that might be your problem right there. This is all assuming you have the pump/sender combo unit - older trucks have a separate pump and sending unit - the sending unit is on the side of the tank behind the tire.

As they say, assembly is the reverse of removal. The rubber seal took some coaxing to get into place, a little light/thin smear of grease on the rubber helped. Then hook everything up, turn on the key, listen for the pump to run - if it does run, wait till it stops, then turn the key off and on again, repeat this a couple times to build pressure back up before you attempt to start. Just remember, you are messing with wiring in the fuel tank, so if your not sure what your doing, might let someone else do it or ask someone to help.

Other than that bit of warning, it was one of the best bang for the buck fixes that I've ever done.

The wire that was broke on mine was almost all gone, I bet 90% of it was missing - it was very brittle, almost looked like old rotten brown cotton string or something. I put a multimeter on it and check the resistance throught the range of the unit, mine has some obvious dead spots, but it works 1000x better than before - good luck!


Steve