Fuel Guage Intermittent

[Puremuscle]

I have a problem with the fuel guage registering and not. At times it reads the amount of fuel in the tank and then begins to drop to "E". At times it reads "E" for a while them climbs back to the fuel level. It can not read a level for weeks at a time then suddenly i look down and it's registrering...Any suggestions?

Thanks

 

[92exp4x4]

You have a short or breake somewhere in the sending unit wiring or the power supply to the gauge. Look at the harness under the truck to see if its been damaged anywhere. Look for places where it goes through the body and may have been cut.

The guage cluster must be taken out to look at it. There is a flexible circut board on the back and it may have a short or burnt spot on it. As long as you can tell how much fuel you have by the Trip odometer, it may not be worth the time and aggravation of tearing your truck apart to find it.

 

[Puremuscle]

Yeah, I'm determining how much fuel is left based on miles traveled. However, sometimes I have other drivers, driving and they don't seem to get it...Guess i shouldn't let them drive...Thanks, I'll look for a wiring issue.

 

[movieguy73]

just dont try to buy a sending unit only.
they cost more then the FP assembly with everything.
lol

 

[Puremuscle]

Yeah, that sounds crazy. From what i read you have to either drop the tank or cut a hole in the floor, to replace the sending unit, it would be wise to replace everything while you are there.

 

[92exp4x4]

Yeah, that sounds crazy. From what i read you have to either drop the tank or cut a hole in the floor, to replace the sending unit, it would be wise to replace everything while you are there.

Exactly, why go through all the trouble just for the sending unit only, when the pump could go the next day

 

[josh000888]

fuel gage repair worked finally

Ok, I had a similar problem with my 91 and here's what I did. I first checked that I had a good ground and it wasn't a circuit issue or fuse. That wasn't the problem. Then I checked the connector to the pump/sending unit (up under the rear wheel well) with an ohmmeter set on the 200 ohm scale. With the connector tab facing the right, you want to probe the upper left with the positive and the lower left with the negative and check the resistance. If the tank is full, it should read somewhere around 160 ohms. If the tank is empty, it should read about 15 ohms. If you are not getting these readings from the sending unit, your sending unit is bad and you will have to drop the tank. I dropped the tank and changed out the pump/sending unit. DO NOT buy the cheap crap they sell at Advance/Auto Zone. Buy a Carter unit from NAPA. Trust me. I screwed up and didn't check the resistance of the 1st new nuit and had to drop the tank again once I found it it was a bad unit!!! (how to spell stuuuped) Whatever you do, do bench test the unit with an ohmmeter to make sure it works. You can raise the float up and down and it should fall into the above ohms readings.

So I get everything back together and go and refill my truck up only to find that replacing the sending unit/pump was not the full problem. At this point i was getting shall we say just a bit agitated. I went to two different shops and they both told me it was a bad sending unit. I knew this wasn't the case so I did some further research. And by luck, I found an article that it might be the slouch (sp) module. I asked myself, wtf would a slouch module be and do? Well, it is a small circuit board that plugs into the instrument cluster vertically adjacent to the gage and I didn't bother contemplating what it did for too long, so I couldn't tell you. all I knew was that that was probably the item that I needed to replace. You might be able to find one on here or at a junk yard, but I was only able to find one at the dealer. you may be able to replace the whole instrument cluster as another option. I went the dealer route. It's another 100 dollar part that prolly costs ford 3.00 to make. When removing the instrument cluster, you have to disconnect a couple of electrical connections and the speedometer cable. The cable came off fairly easily with the help of a long screwdriver. you have to squeeze the flat side of the connector for it to release. Once you get the unit out, I cleaned it up for the 1st time in 217,000 miles and snapped in the new slouch module. Then I set the unit back in place, and wah-laa! my fuel gage worked for the first time in 2 years! Make sure if you take the plastic cover off the cluster that you do not touch any of the gages as they are more sensitive than a pregnant woman. A tip would be that it sure helps if you have someone with small hands that can reconnect the speedometer cable for you. It was a *****, but my wife was finally able to get this connected for me and it only cost me a night out on the town. hopes this helps!.

 

[josh000888]

Ok, I had a similar problem with my 91 and here's what I did. I first checked that I had a good ground and it wasn't a circuit issue or fuse. That wasn't the problem. Then I checked the connector to the pump/sending unit (up under the rear wheel well) with an ohmmeter set on the 200 ohm scale. With the connector tab facing the right, you want to probe the upper left with the positive and the lower left with the negative and check the resistance. If the tank is full, it should read somewhere around 160 ohms. If the tank is empty, it should read about 15 ohms. If you are not getting these readings from the sending unit, your sending unit is bad and you will have to drop the tank. I dropped the tank and changed out the pump/sending unit. DO NOT buy the cheap crap they sell at Advance/Auto Zone. Buy a Carter unit from NAPA. Trust me. I screwed up and didn't check the resistance of the 1st new nuit and had to drop the tank again once I found it it was a bad unit!!! (how to spell stuuuped) Whatever you do, do bench test the unit with an ohmmeter to make sure it works. You can raise the float up and down and it should fall into the above ohms readings.

So I get everything back together and go and refill my truck up only to find that replacing the sending unit/pump was not the full problem. At this point i was getting shall we say just a bit agitated. I went to two different shops and they both told me it was a bad sending unit. I knew this wasn't the case so I did some further research. And by luck, I found an article that it might be the slouch (sp) module. I asked myself, wtf would a slouch module be and do? Well, it is a small circuit board that plugs into the instrument cluster vertically adjacent to the gage and I didn't bother contemplating what it did for too long, so I couldn't tell you. all I knew was that that was probably the item that I needed to replace. You might be able to find one on here or at a junk yard, but I was only able to find one at the dealer. you may be able to replace the whole instrument cluster as another option. I went the dealer route. It's another 100 dollar part that prolly costs ford 3.00 to make. When removing the instrument cluster, you have to disconnect a couple of electrical connections and the speedometer cable. The cable came off fairly easily with the help of a long screwdriver. you have to squeeze the flat side of the connector for it to release. Once you get the unit out, I cleaned it up for the 1st time in 217,000 miles and snapped in the new slouch module. Then I set the unit back in place, and wah-laa! my fuel gage worked for the first time in 2 years! Make sure if you take the plastic cover off the cluster that you do not touch any of the gages as they are more sensitive than a pregnant woman. A tip would be that it sure helps if you have someone with small hands that can reconnect the speedometer cable for you. It was a *****, but my wife was finally able to get this connected for me and it only cost me a night out on the town. hopes this helps!.

 

[Joe Dirt]

Great info- thanks for the writeup!

 

[Puremuscle]

yeah, i read that same thing about the anti slosh circuit. I'll try that out this weekend. I have gotten use to reading the thing by miles, but it will be nice to look at the guage for a change and not use math to figure out how far i can go. Not only htat, ther has been a time or two when i forgot toreset the odom and had to do some walking.

 

[Macgiobuin]

Could be the float itself. On some models, the float is a brass cylinder about 2 in long, one inch diameter. They get hairline crack in them and eventually fill with fuel. The crack on mine was invisible; I needed a magnifying glass to see it. Even if the tank is full, the gauge will read empty. But then when the tank is almost empty, the float empties of fuel and it floats again. Then you fill the tank, and it works for a few days til the float fills with fuel again. I cut mine off and replaced it with a plastic float from a carburetor kit; just soldered it onto the float rod so that it works the same as the factory brass float.