1993 Ford Explorer XLT Fuel Gauge Not Working

[mr cribb]

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!

The only “extra” thing I have done, is I added an additional ground at the new assembly pigtail, because I was checking to see if I was getting a good ground through the harness itself. Yes, I can easily get to the pigtail for additional testing.

Backstory is: it’s lifted 5.5” on 33’s through the A4LD. I’m sure there’s some economy loss there.

I’m looking at other suppliers for a replacement pump assembly. I found one unit that actually lists the ohm readings full and empty, whereas none of the others do, nor could I find that information on the assembly I bought.

Just for clarification, I should only find a reading on the yellow/white stripe wire, and no where else correct? I’m good with checking for voltage on my multimeter, but I’ve never used it for ohms until now. I want it on the 200 digit value for this test right? I will include a picture since there’s so many different suppliers of meters.

Arrow of the dial is where I was using it at:

 

[Roadrunner777]

Yes, you're on the right track. Ideally, you will open the connector and measure ohms (resistance) on the fuel pump side of the connection, one probe on Yellow/White, the other on Black/Yellow. That will narrow it down to just the sensor itself. You do not need to worry about which probe (red/black) on which wire... resistance does not have polarity. You meter is set up perfectly. I'm going to post this and then scan the schematic for this particular circuit... I'll have that up in about 10 minutes.

 

[Roadrunner777]

 

[mr cribb]

It finally stopped raining long enough to check what you said. On the harness side for the truck I got 0.3 ohms, and like before the gauge on the dash moved around from beyond empty to just below 3/4’s. Applying power to the gauge cluster with it all hooked up together sent it back to empty, so I think it’s safe to say the sending unit is bad or non operative.