Fuel Guage

1990RangerinSK · Jun 27, 2017

My fuel guage hasn't worked since I bought the truck. I can get by without it, but I never know how much gas I really have, so it would be nice to fix it.

The interesting symptom is that when you turn the key off, the guage rises to 1/4 tank. When you turn the key on, it falls to Empty.

Can anybody shed some light on what the problem might be? I know there's a float in the tank that has a sending unit that sends a signal to the guage, but that's about all I know.

Thanks!

Plum Ranger XLT · Jun 27, 2017

The sending unit to the gauge could be bad. I know how you feel because I once had a 1984 Ranger that I bought used and the fuel gauge didn't work in it either and it turned out to be the sending unit to the gauge. I would reset the trip counter and drive about 250 miles or so and fill up with gas and reset the trip counter again. Not once did I run out of gas doing it that way even with the gauge not working.

1990RangerinSK · Jun 27, 2017

I'm guessing the sending unit is on top of the tank, right? Or is it inside? So for access I have to remove the bed?

ericbphoto · Jun 27, 2017

1990RangerinSK said:
I'm guessing the sending unit is on top of the tank, right? Or is it inside? So for access I have to remove the bed?

Either remove the bed or drop the tank. My preference is remove or lift the bed. Once you get the bed bolts loose, you could leave the rear bolts in their holes to keep the bed in place, then lift the front of the bed and prop it on blocks of wood. You will need to remove the screws holding the filler neck in place. If you take the bed completely off, you will need to unplug the wiring connector for the rear lights. The bed isn't heavy. 1 person could lift and prop up the front end. 2 people can easily lift it completely off. Worst part is getting the bolts loose.

The fuel pump and level sending unit are an assembly that lifts out of the tank. You may want to have a new gasket on hand for the hole they come out of.

I had an '88 F150 years ago with dual tanks and both senders were bad. Never did fix those. I used the trip odometer method.

Eric B

Mark_88 · Jun 27, 2017

Removing the bed is the best way but if it hasn't been off in 27 years you may find some rust issues with the bolts.

They are T-55 if original with C-nuts (clips with threads) on the frame. that hardware can be replaced as needed but if you soak the bolts from the bottom around the C-nuts and use a breaker bar they might come out easy.

The bed is light enough for one or two people to lift off or just prop it up unless you are going to do other work.

Good time to check the spring hangers and shock mounts too but removing the bed for that work later will be a breeze within the next three or four years.

If they use salt or chemicals on the roads in SK check the frame over while you're in there just so you know...

1990RangerinSK · Jun 27, 2017

Ok, thanks. Am I right that the floor of the bed can be removed? Or are the screws/bolts that seem like they hold it holding the entire bed, including the sidewalls?

ericbphoto · Jun 28, 2017

Those bolts are holding the whole bed to the frame. They can be a pain. I hit mine with penetrating oil from underneath. I think I used WD-40. I then needed a breaker bar with a handle extension to break them loose and I am NOT in any of the "salty" parts of the country. Lately, I have been having better luck with PB Blaster vs WD-40. If you can spray them down several times over a few days, that may help. Not sure if an impact is a good idea or not. It might just tear up the C-nuts.

Mark_88 · Jun 28, 2017

I prefer PB Blaster also...WD-40 doesn't work as well on badly rusted items in my experience but if that's all you have...

I tried an impact gun on mine and that only managed to annoy the rust monsters. Breaker bar works find but I did actually need to use a pipe extension so I was cranking with about 4 feet of bar. that gets a bit tricky if the bolt heads are dirty so clean them out good before applying the socket and press down firmly on it while cranking.

A stripped head can be easily taken off with a grinder using a cut off blade so if you don't have that stuff handy before you start it will save time to gather things just in case.

ericbphoto · Jun 28, 2017

... and that T-55 needs to be good quality. A cheap one will twist, break, strip, etc. Causing you to use many curse words and consume much adult beverage out of frustration.

I know this might sound bad. But It's not really. If you're prepared. It will be ok.

Eric B

AgPete139 · Jun 28, 2017

+1

Definitely spray the critical bolting areas under the bed (connecting bolts to the frame) with PB blaster hours before you try to remove the bolts.

Use a quality Torx bit, indeed. Cheaper ones will strip, which means you will have a much harder time removing the bed or grinding the head off with a grinder. I've done this twice to two different Rangers that weren't nearly as old as yours. Also, use a breaker bar for additional torque to break loose the bolts. Don't just try to use a small socket wrench at an awkward angle.

1. Spray all areas with PB blaster, WD-40, etc. Wait 2+ hours.
2. Remove the screws inside the fuel door on the driver's side of your bed.
3. Remove the tail light + license plate wiring harness by the bumper.
4. Remove the 6-8 T-55 bolts in the bed of your truck.
5. Get a second hand to lift off the bed. Be careful to now bend or break the fuel filler neck. (I actually use a chain hoist in my garage with tie-down straps. Also, if you see cracks in the filler neck, use quality RTV to seal them.)
6. You now have access to the fuel pump.

Good luck.

1990RangerinSK · Jun 28, 2017

Before I get too far into a reply, to EricbPhoto: Thank you for your service. I'm Canadian, but I still appreciate your military service.

With that out of the way, I suspect it's going to be a while before I can do the job. You've given me some great tips here, so I'll see if I can tuck this away somewhere so that I can have it when I'm ready. Just the same, thanks for the help and the tips.

I don't know if it would be easier or not, but what's involved in dropping the tank?

Mark_88 · Jun 28, 2017

Dropping the tank can be easy too but you would probably want to drain the tank doing it that way. Not a big issue if you have next to no gas in it but otherwise you need to store that gas somewhere and they hold 60 litres or so and that is three or four large containers...unless you have farm equipment and a gas pump on site.

Biggest problem is working while laying on the ground or under the vehicle looking up. If you have a lift it is actually pretty easy. A lift with a stand for removing the tank is even better because you won't have to drain it (much).

The straps may need to be replaced or you may find the support beam where the front strap hangs may need work. Then you might want to drop the tank and remove the bed for better access with torches and welders.

Is the tank metal or plastic?

Makes only a small difference either way but the metal tanks sometimes need more work like cleaning rust and patching seams. Makes no difference what method you use as far as tank type though.

1990RangerinSK · Jun 30, 2017

Thanks, Mark. I'll keep that in mind.

AllanD · Jun 30, 2017

THIS IS REALITY as I've under stood it..

Fuel gauges in any transport device, be ir a car a plane or a ship CANNOT BE TRUSTED EVER!!!

I only believe a fuel level gauge when it says "Full" when I have put a measured volume of fuel into that tank and/or seen standing fuel in the filler pipe.
and conversely only trust one that says "empty" immediately after the engine has stopped running from fuel starvation.

And that is from someone who is a trained instrumentation technician who hand wired his own Ranger with duel tanks.

AD

rangerpilot · Jul 1, 2017

AllanD said:
THIS IS REALITY as I've under stood it..

Fuel gauges in any transport device, be ir a car a plane or a ship CANNOT BE TRUSTED EVER!!!

I only believe a fuel level gauge when it says "Full" when I have put a measured volume of fuel into that tank and/or seen standing fuel in the filler pipe.

and conversely only trust one that says "empty" immediately after the engine has stopped running from fuel starvation.

And that is from someone who is a trained instrumentation technician who hand wired his own Ranger with duel tanks.

AD

FWIW ... in small piston aircraft (not certain for transport so don't look too deep), we are taught the gauge is only certified to be accurate at empty.

Trust but verify EVERY flight and establish know indicators (fuel flow per hour for aviation and miles per gallon/tank in vehicles.

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