Ohm reading interpetation

[redlinj]

After running the appropriate tests, my fuel gage is shot! The ohm readings on the sending unit, which is stamped 240 ohm, is 255 and will go no lower than 61at which time my fluke tester goes to OL. is this reading OK?

 

[bruceb58]

Should never go to OL. OL is open.

 

[gm280]

Do you have another meter to read the sender? I would check with another meter if you have one to verify those readings. How did you verify the actual gauge was bad?

 

[redlinj]

I will check with another fluke meter. I removed the gauge and wired directly to the battery. No movement of the needle. Then removed the pink sender wire and jumpered the sender terminal over to ground and still nothing. The arm of the sending unit is pretty much all the way up/full when it goes from 61 ohms to OL. My feeling is that the sender is functional and the gauge is shot. Just didn't have another known good gouge to check it with. Yes, its only $20 or so for a new one but I LOVE wasting my time. I find that 12v dc electrical problems can be frustrating AND fascinating at the same time.

 

[mjf55]

So in my opinion, the sender is MOSTLY working. The spec calls for 30 - 240 ohms, in which yours is very close. To me the troubling part is the OL reading. That indicates something wrong at the full up. It is good enough to test your gauge with, but i would get a new one, especially since you have the unit out.

Since it is out, i would cover the tank hole ( where the sender was ) and now hook up the semi-working sender to the gauge with new short wires and test the gauge. Easy way to test the gauge without your existing wiring. That way, inaddition to getting a new sender, you will jnow if you need a gauge and or new wiring.

Remember, cover that tank hole so there are no fumes to go boom.

 

[bruceb58]

My feeling is that the sender is functional and the gauge is shot.

You are measuring the sender with all the wires disconnected right? If it goes to OL, the sender is not working properly.

 

[redlinj]

Yes, no wires connected and the sender out of the tank. Only goes to OL when the arm is all the way up or in the full position. So if the arm is half way or tank is half full, the ohm reading should be half way between 30 and 240 ohms---or in my case, mid point of 61 and 255 ohms. Just trying to play devil's advocate. Don't know if this makes a difference but the tank is rectangular, but the front is 12" high and slopes down to 6" at the rear. In other words, looking from the front or rear, the tank has 2 parralel sides. Whereas looking from either side it only has 1 parallel side.

 

[bruceb58]

Buy a new sender. Yours is bad.