1993 Ford Explorer XLT Fuel Gauge Not Working

[Liam Moonan]

Hi, the fuel gauge on my 1993 Ford explorer xlt hasn't been working for quite some time. I bought it in late August, and the previous owner said he got the fuel pump replaced 3-4 years ago, and when he got it back the fuel gauge stopped working. I believe it has to do with the wiring in the tank because all the other gauges work fine, but I have no experience with this type of thing. If anyone has a diagram for the tank, that'd be great. I suspect it's the ground wire, but wouldn't that mean the fuel pump wouldn't work? It pumps fuel to the engine fine. Any help is greatly appreciated.

 

[Dora 1993]

I would like to know this as well. Mine doesn't work either. However mine will sometimes work periodically once in a blue moon for a little while. Particularly during a very long drive. Does yours do this as well? Or have you literally never seen it move ever?

 

[Rhett]

There is a float on the sender/pump unit. It's attached to the pump/sender unit via a metal arm. It looks kind of like an old-style toilet tank float, and works kinda the same way, for lack of a better mental image. The float floats on top of the gas and moves up and down with the level of gas in the tank.

Some brands of fuel pumps floats do not behave well -- it's a good idea to hook them up outside the tank prior to install, and test the float arm position vs. your fuel gauge before install. Also -- I've seen the float develop a leak, and then it sinks to the bottom of the tank and never rises (giving you an empty tank reading on your gauge).

In the case of the OP it's possible your gauge is bad, or it's possible that the float is either poorly installed or bad, since your previous owner told you that it quit working when the pump was replaced In the case of the op it's possible the installer re-used the old float, and it wasn't any good anymore, or the new float wasn;t working correctly. It's also possible they installed it and didn't make sure the float/arm assembly was free to move. If it contacts any baffle / side of the tank it won't read properly. It sits down in a low spot, and if you don't orient the pump properly, the arm will hit the bottom/side of the tank baffle.

Dora 1993 -- yours may be the gauge, since it is intermittent, but you cannot rule out the sender either, since it's electrical also. The float/arm assembly moves across a sensor, and if the sensor is not consistent, you'll get inconsistent readings. I'd make sure the connections to the pump are ok, too.

 

[Roadrunner777]

In a '94, the wire from the sensor to the dashboard gauge is yellow with a white stripe. You can access it from the harness leaving the tank, or at a connector under the brake master cylinder. Measure the resistance in ohms from this lead to ground. A full tank should read about 145 ohms, where an empty tank should read around 22 ohms. Be sure you have a decent ground when making this measurement. If the resistance is ok, then so is the float sensor.

If the float sensor tests out ok, then there is an anti-slosh module built into the instrument cluster to keep the fuel gauge needle from bouncing all over the place, and others here have had this module go bad. It's a plug-in thing, once you find one and learn how to remove the instrument cluster, it's not a hard job. If you do so, replace all the instrument cluster illumination lamps, whether they are working or not. There is no better time to do this.

I am not a regular here anymore, but I try to check-in every week or two. I hope this helped!

 

[Liam Moonan]

In a '94, the wire from the sensor to the dashboard gauge is yellow with a white stripe. You can access it from the harness leaving the tank, or at a connector under the brake master cylinder. Measure the resistance in ohms from this lead to ground. A full tank should read about 145 ohms, where an empty tank should read around 22 ohms. Be sure you have a decent ground when making this measurement. If the resistance is ok, then so is the float sensor.

If the float sensor tests out ok, then there is an anti-slosh module built into the instrument cluster to keep the fuel gauge needle from bouncing all over the place, and others here have had this module go bad. It's a plug-in thing, once you find one and learn how to remove the instrument cluster, it's not a hard job. If you do so, replace all the instrument cluster illumination lamps, whether they are working or not. There is no better time to do this.

I am not a regular here anymore, but I try to check-in every week or two. I hope this helped!

Thanks for the reply. In order to do the test with the ohm meter, do you have to drop the tank, or is the wiring visible from under the car? I would go check but it is currently 12°F and snowing lol. I may have to wait till spring to work on it haha.

 

[Roadrunner777]

Thanks for the reply. In order to do the test with the ohm meter, do you have to drop the tank, or is the wiring visible from under the car? I would go check but it is currently 12°F and snowing lol. I may have to wait till spring to work on it haha.

I can get to mine through the left rear wheelwell. But, I have been in there so many times, who knows how many factory tie-downs I have broken on that cable, so maybe you can't get to it. Just have to take a look at yours.

Like I said, another spot is a connector under the brake master cylinder. If you look under the master cylinder, there are a pair of round connectors, each with 8 conductor positions. One of those connectors will also have the yellow/white stripe wire, and you can test it there. So, you will have to figure out which connector, has that wire, open the connector, and figure out which side of the connector goes to the fuel sensor. Now if you get a failure there, it could be the sensor, or the wire run to the sensor, so there is an added complication, but that's a second test point that is easier to get to. I'd test there first because if it tests ok, you know the sensor and wiring to the tank is ok.

Now, all this is for the '94. It is likely that the connectors and wire colors are the same, but I cannot verify that. I'd do pictures, but it is sub-zero here and I would have to break the ice off my hood to get it open. Good Luck!

 

[larrydd999]

If you test using the wire in the connector by the brake master cylinder, you will likely find the resistance will either be infinite (open circuit - broken wire) or around 240 ohms (float resting on the bottom of the tank). If your tank was - say - around half full, the resistance would be lower, and if full it should be around 33 ohms. These numbers are nominal and can vary a bit from sender to sender.
Dora, your issue is likely the 'anti-slosh module' on the back of the instrument panel, as mentioned above. My '92 has the same problem, sometimes it works, most of the times it reads randomly between full and empty. I'm reluctant to remove the panel since 25 year old plastic has an annoying habit of breaking so I'm looking into a way to remove the module without pulling the entire panel. I do have a 'parts vehicle' that I may practice on, and if I find a way I'll post it.

 

[roscoe 0202]

anti slosh module will affect all gauges except alt ind.
roscoe

 

[Roadrunner777]

If this ends up being in the gauge cluster, and you can live with it until warmer weather... the thing is, you have to flex a big plastic bezel, and it's going to be brittle under normal conditions. Be very careful!

 

[Helton]

Bom dia, moro no Brasil. Tenho uma Explorer 1994 Xlt. O indicador de nível combustível esta sempre acima do cheio. Pode ser o indicador ou o modulo?

 

[allmyEXes]

Bom dia, moro no Brasil. Tenho uma Explorer 1994 Xlt. O indicador de nível combustível esta sempre acima do cheio. Pode ser o indicador ou o modulo?

translated by google

Good morning, I live in Brazil. I have an Explorer 1994 Xlt. The fuel level indicator is always above full. Can it be the indicator or the module?

 

[roscoe 0202]

Helton if your guqages are all max it is the module on the back of the guage cluster if it is just the fuel guage i'd bet that it is grounded out somewhere
roscoe

 

[Helton]

Apenas o medidor de gás que está acima do nível máximo.
Only the gas gauge that is indicating above the maximum level.

 

[allmyEXes]

Then your yellow fuel sending unit wire is grounded somewhere between the sending unit and the fuel gauge instrument.

 

[mr cribb]

Keeping with the theme here, I searched for my issues and decided to bump an old thread as opposed to starting a new one.

When I took possession of my newest explorer a month ago, the gauge didn’t work, and the PO said it crapped out somewhere in the three years it sat.

I pulled out the original pump and swapped in a new one. Now my gauge reads at a 1/4 tank on the gauge, with 16 gallons in the tank. I haven’t tested the ohms at the two points mentioned, but I bought a discount pump assembly with a great warranty, but I wonder if my problems lie with the new part, or is it electrical?

Now the oem pump worked and everything was connected as far as the sending unit was concerned, but it read nothing.

I even swapped out fuel gauges with a spare I had laying around, same thing, it reads 1/4 tank. I even played with the gauge by moving it to full to see if it needed to be calibrated, and it instantly went back to a 1/4 tank.

Now I’m up for suggestions, and hoping that it doesn’t involve dropping the tank again as it fought me tooth and nail this go around.

 

[Roadrunner777]

Testing the ohms will tell you if the sender it working or not. That's explained earlier in the thread.

 

[mr cribb]

Testing the ohms will tell you if the sender it working or not. That's explained earlier in the thread.

I tested the ohms this afternoon, and I got 13.6 ohms.

My gauge reads empty, I have 158 miles on my trip for this tank of gas. I bought 16 gallons after changing my fuel pump assembly.

I have tried two different anti slosh modules, and no changes.

When I conducted the test, and before I reconnected the plug, I noticed the gauge was maxed out at full, and after I reconnected the plug it went right back to empty.

I need some help.

 

[Roadrunner777]

Yeah, so you have roughly 6 gallons left or about 40% full.

Now, empty is 22 ohms, and the resistance only goes up from there, to 145 ohms for a full tank. Meaning, the resistance should never be lower than 22 or higher than 145.

You're getting 13 ohms. If you are measuring that at the pigtail to the pump, then the problem is in the sending portion of the fuel pump. Like, maybe the float fell off or something. If you measured that at the pigtail, your problem is on that side, not the gauge cluster.

 

[mr cribb]

Yeah, so you have roughly 6 gallons left or about 40% full.

Now, empty is 22 ohms, and the resistance only goes up from there, to 145 ohms for a full tank. Meaning, the resistance should never be lower than 22 or higher than 145.

You're getting 13 ohms. If you are measuring that at the pigtail to the pump, then the problem is in the sending portion of the fuel pump. Like, maybe the float fell off or something. If you measured that at the pigtail, your problem is on that side, not the gauge cluster.

I did my reading at the plug under the master cylinder.

 

[Roadrunner777]

Ok, well, that adds a segment of wiring to the equation. Depending on how you routed the wiring when you installed the new pump, you may be able to get to the pigtail. That's really the last test point, and it will tell you if you have a bad sender or something in the chassis wiring.

Now, something changed, and maybe you can fill in that blank:

Last Sunday you wrote: I pulled out the original pump and swapped in a new one. Now my gauge reads at a 1/4 tank on the gauge, with 16 gallons in the tank.

Then, yesterday, you wrote: My gauge reads empty, I have 158 miles on my trip for this tank of gas. I bought 16 gallons after changing my fuel pump assembly.

Did you do anything other than drive the 158 miles? I'm just trying to fill in the blank.

And, I did some math... just to do it:
Empty: 22 ohms
Full: 145 ohms
You have about 40% of a full tank, so that should come out to about 70 ohms.

It is almost as though the sender has the wrong resistance value range. I suppose one thing I might do is go back to the supplier with the part number, if you still have the box and stuff, and make sure they shipped the right one.

See if you can get a reading off the pigtail. If not, then I'm thinking you are going to have to get to it somehow, even if that means dropping the tank.

Good Luck!