Fuel gauge sender on T180

[bobbie-g]

The fuel gauge on my T180 has been showing full for way too long. I'm down to about an inch of fuel in the tank and it still reads completely full (round gauge on left panel, non-deluxe panel). I unplugged the wire harness at the sender, and the gauge then read empty. The sender at this point has 33 ohms of resistance. I'm betting the sender is mechanically stuck at the top, or some linkage has come apart to cause the electrical mechanism to move to the full position. I was warned by a Bobcat mechanic to not remove the sender from my 751 unless I had a new one to put in the tank. The used one (plastic body) evidently swells when it's removed and can't be replaced. The problem on the 751 is compounded by the fact that only a triple-jointed person with skinny and very long arms can reach it (impossible to see it). Any thoughts on the T180 sender? Anyone know what the normal range of resistance is for the sender? Manual doesn't say. Can it be removed and replaced? At least it's easily accessible. ---RC

 

[Fishfiles]

What I would do is buy the new sending unit and disconnect the plug on the sender in your machine and connect the plug off your wiring harness to the new sender with that sender out the tank and work it manuelly up and down the shaft and you will know if that will fix your problem before going thru the hassel of changing it --------with the wiring disconnected from the sender and you read empty and it connected and you read full I 'd give it a 99.9% chance it is the sender thats bad ------------------you know the tool that fits the new style quick couples on the machine happens to fit the sending unit of the fuel tank , but not too many model machines can you get access to get it on , a channel lock pliers works about the best

 

[bobbie-g]

What I would do is buy the new sending unit and disconnect the plug on the sender in your machine and connect the plug off your wiring harness to the new sender with that sender out the tank and work it manuelly up and down the shaft and you will know if that will fix your problem before going thru the hassel of changing it --------with the wiring disconnected from the sender and you read empty and it connected and you read full I 'd give it a 99.9% chance it is the sender thats bad ------------------you know the tool that fits the new style quick couples on the machine happens to fit the sending unit of the fuel tank , but not too many model machines can you get access to get it on , a channel lock pliers works about the best

Fishfiles, good idea about using the new sensor before removing the old one. The nearest new sensor is a hundred miles away, so I pulled the old one. Looks OK, but doesn't work with the gauge. Moving the float all the way up and all the way down does not affect the gauge, it always reads full. So much for guessing the float was "water logged" and sinking (although then it should always read empty). The resistance on the sensor changes from 33 ohms (bottom) to 18 ohms (top). But with the sensor unplugged (essentially thousands of ohms or more) the gauge reads empty. I'm wondering if the sensor has gone south and is partly shorted. Only way to tell that I can figure out is to get a new one like you suggested and plug it in. I think it's still possible that the meter circuit is goofed up. Oh joy. Removing the sensor was a blast, turned hard all the way out, using water pump pliers. It's manufactured so that a 1-5/8" socket spins on it, and a 1-11/16" won't fit over it. OK, I'll let you know how the new sensor turns out in about 3 weeks when we make the trip to the dealer. :-( ---RC

 

[Fishfiles]

Fishfiles, good idea about using the new sensor before removing the old one. The nearest new sensor is a hundred miles away, so I pulled the old one. Looks OK, but doesn't work with the gauge. Moving the float all the way up and all the way down does not affect the gauge, it always reads full. So much for guessing the float was "water logged" and sinking (although then it should always read empty). The resistance on the sensor changes from 33 ohms (bottom) to 18 ohms (top). But with the sensor unplugged (essentially thousands of ohms or more) the gauge reads empty. I'm wondering if the sensor has gone south and is partly shorted. Only way to tell that I can figure out is to get a new one like you suggested and plug it in. I think it's still possible that the meter circuit is goofed up. Oh joy. Removing the sensor was a blast, turned hard all the way out, using water pump pliers. It's manufactured so that a 1-5/8" socket spins on it, and a 1-11/16" won't fit over it. OK, I'll let you know how the new sensor turns out in about 3 weeks when we make the trip to the dealer. :-( ---RC

Boobie-g , you could have the dealer UPS the part to you , frieght charges would have to be less than fuel and a lot sooner than 3 weeks ------------to check the wiring and the gauge you can put a jumper into the end of the plug and the gauge should go all the way to full , pull the jumper out and it should go to empty , it is a pretty common to have a sender go out , I have seen quite a few times on certain models that the plugs wires get rubbed right at the plug from hitting the bottom of the sunstrand -----------talking about hard all the way out , I remember once where the threads came out the plastic tank while unscrewing a sensor and the motor had to be removed and the tank changed

 

[bobbie-g]

Boobie-g , you could have the dealer UPS the part to you , frieght charges would have to be less than fuel and a lot sooner than 3 weeks ------------to check the wiring and the gauge you can put a jumper into the end of the plug and the gauge should go all the way to full , pull the jumper out and it should go to empty , it is a pretty common to have a sender go out , I have seen quite a few times on certain models that the plugs wires get rubbed right at the plug from hitting the bottom of the sunstrand -----------talking about hard all the way out , I remember once where the threads came out the plastic tank while unscrewing a sensor and the motor had to be removed and the tank changed

OK, let's close out this thread. Fishfiles, your 99.9% guess was 100% right: bad sender. Old one read 18 ohms at the top, 33 ohms at the bottom. New one read 33 ohms at the top and about 230 ohms at the bottom. The threads on the new one are just fine, I lubed them with silicon spray and it turned in by hand right to where it seated on the rubber washer. I just snugged it up with the waterpump pliers. The old one had obviously swelled up a lot, and I never could get it to thread back into the tank properly. I would advise against pulling the sender unless you planned to reinstall a new one. New one is about $75. ---RC

 

[Fishfiles]

OK, let's close out this thread. Fishfiles, your 99.9% guess was 100% right: bad sender. Old one read 18 ohms at the top, 33 ohms at the bottom. New one read 33 ohms at the top and about 230 ohms at the bottom. The threads on the new one are just fine, I lubed them with silicon spray and it turned in by hand right to where it seated on the rubber washer. I just snugged it up with the waterpump pliers. The old one had obviously swelled up a lot, and I never could get it to thread back into the tank properly. I would advise against pulling the sender unless you planned to reinstall a new one. New one is about $75. ---RC

That's great you got it fixed , it's nice to see a close out of a thread as you put it , you never know sometimes what were the results , and those ohm valves could be helpful to someone in the future -----only other thing I could think of to help someone do this job would be to blow off or pressure wash the area before pulling the sender and it don't hurt to put some dielectric grease on the plug connectors