How to test a fuel gauge?

fpappal · Jan 7, 2016

If I connect a fuel gauge quickly to a battery should the needle move? The fuel gauge in my 203 has never worked. I have the gauge out and I hooked it up to a battery briefly. The needle did not move. I simply connected one of the wires to positive and the other wire to negative on the battery.

Dieseltech · Jan 7, 2016

When testing the dash gauge on the machine I just ground the sending unit wire with the key on if gas, or engine running if diesel. A good gauge on MF equipment will move the needle from empty to full when the wire is grounded.. MOST times the sending unit is the problem either the float has a hole or the resistance coil is bad.

fpappal · Jan 7, 2016

Right now the dash is removed and the entire wiring harness is in pieces. The tank is sitting on the floor. So I need to somehow test the gauge with it not hooked up to anything. The key switch also did not work so that is getting replaced. Any suggestions?

ptfarmer · Jan 7, 2016

On the gauge if you hooked the + terminal of the gauge (which should be on the "E" side of the gauge) to the positive battery terminal, and the sender terminal on the gauge to the negative battery terminal it should go up to full.

The fuel gauge works off of resistance from the sender in the tank. To test the sender you remove the sender from the tank, and hook a ohm meter to it then move the float arm on the sender up, and down. If the sender is working correctly the ohm meter should move when you move the float arm, if the ohm meter doesn't move the sender is bad.

fpappal · Jan 8, 2016

Thank you. My gauge actually has a terminal in the middle and one at the top middle. Either way the needle will not move. I
will check the sending unit this weekend.

ptfarmer · Jan 8, 2016

The sender should read from 10 ohms (empty) to 240 ohms (full)

fpappal · Jan 8, 2016

I called MF to order a new fuel gauge and they want $56. I told them to hold off till I get some more information. Will any generic fuel gauge work or do I need one that works with my sending unit? This website does not even sell a fuel gauge for a MF203. I was going to check with Tractor Supply, they usually have a bunch of generic stuff.

Any thoughts?

Phil Tibbetts · Jan 8, 2016

From what I have seen almost all AC 2 1/8 diameter gauges are the same ohm rating, and it is in small writing on the dial face.

ptfarmer · Jan 8, 2016

You need.
Fuel gauge 193950M91 (gas or diesel)
Sender 189605M2 (tractor serial number 659002115, and up)
Sender 189132M91 (used on prior tractor with serial number 659002115)

ptfarmer · Jan 8, 2016

There are at least 11 different ohm range fuel gauges, and senders, there is no one fits all. The gauge, and sender has to have the same ohm range.

fpappal · Jan 8, 2016

Yes you are correct. I just looked and it says 12 Volt, 30-240 OHM

Should there be continuity between the two terminals? Using my ohm meter I am not getting a beep when connect to the two terminals.

fpappal · Jan 8, 2016

Thank you. Looks like I will be spending some money tomorrow.

Phil Tibbetts · Jan 8, 2016

I think you will find that is a very common range in older equipment that used gauges made by AC Delco.

How to test a fuel gauge?

fpappal

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