fuel gauge reads empty

I have a '95 Ford Ranger with the 2.3 L 4 cyl. The other day I noticed that the gas gauge read empty. First I thought someone had siphoned my gas but when I put more in it only took a few gallons and the gauge still reads empty.

What is the simplest diagnostic procedure I can use to determine if the problem is the gauge, the sender or some other problem? I do not want to drop the tank unless absolutely necessary. All the other gauges work OK and the vehicle has no other problems. Is there a fuse that controls the fuel gauge?

Engineman

Reply to
engineman
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I don't know about the Ranger, but in my experience, the gauge is seldom at fault. It can be anything from a wiring fault, fuse(if it has one), the sending unit, or a bad ground. Use a volt ohm meter to check for voltage at one of the meter terminals. The gauge is usually a heating element wound on a bimetal blade. Not always though. The tank unit is usually a crude rheostat moved by a metal rod connected to the float. The return circuit is via a ground to the chassis. With a metal fuel tank, it usually grounds through the tank shell via the mounting straps.

Steve R.

Reply to
Steve R.

Most of the times I have seen this happen, the float itself is hung in the down position. Certainly, the electricals can be at fault too, but I dont remember ever seeing the gauge itself go bad.

Reply to
hls

Worthless response.

Reply to
twisted

Also a worthless response.

Reply to
twisted

You'll need to get to the wiring harness that goes to the sending unit. Find the wire that comes from the gauge and ground it. The needle should start to go up and peg to "Full." Sometimes, depending on what side the needle is leaning, they will peg to "empty." I haven't found the wire colors for the gauge in my book yet. The wires for the pump are supposed to be: + PK/BK and - Y/W, on the truck side of the harness. Take a test light/meter and find the other +/KOEO. (Key On Engine Off). That will be the gauge wire.

Reply to
twisted

Also a worthless response.

Thank you so much, twisted. From you I take that as a compliment;>)

Reply to
hls

Abpout 80% of the time it's a bad groiund or wiring connection. If it starts working at somewhere around 1/2 to 1/4 full, it is a worn out sender rheostat.

Reply to
clare

It is very seldom that I have seen trouble with these systems. I dont doubt your figures on wiring and grounds...They are the main cause of a lot of auto systems problems.

I used to see the floats hang up every once in a while. They could hang high when you had refueled, and then indicate a full tank until you hit a bump or something. Same way with low fuel.

They arent too hard to troubleshoot, if the OP has a circuit diagram and a VOM, in most cases.

Reply to
hls

I've had them stick UP, but in 40 years I don't think I've seen 2 stick down - and then only for a short time.

Reply to
clare

Pull the tank .. pull the fuel gauge sending unit.

You might have just lost the float, the swing bar if they use one like that .. or the electrical sending unit.

Since your dash is working, this is isolated, it is best to check if electricity is getting TO the SENDING UNIT.

Usually sending units only have one wire, and if that is intact and not cut or broken .. it is usually good.

Soooo ... pull the tank is the best first bet if you wanna do it your self and not do a proper Diagnosis and find out.

Likely it is an open circuit in the fuel pump sending unit, they can test engine starters for being bad with this open circuit test if it is burned out electrically.

So pull the fuel pump sending unit .. put it into a good truck and if it makes that same break .. then it is the sending unit.

Much like testing computer parts.

Likely you might discover how it is broken once to your eye.

Plan two .. hunt down the electrical short in the wiring harness.

I don't think there is a plan three for this connundrum lacking data.

All my best,

sumbuddie wear blind sea

:?

Reply to
Alan B. Mac Farlane

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