1960 (I think) Massey Ferguson MF-35, 4-cylinder Continental Gas engine, Negative ground, still generator type
Replaced old gas tank that did not have a hole for a sending unit with a new one that has a hole. Dash had a hole for a fuel gauge but no fuel gauge.
Ordered new sending unit and fuel gauge.
Spliced into hot wire from key switch ignition to starter button and connected to power terminal of the gauge.
Connected sending unit post to sending unit terminal on gauge. No secondary ground wire from sending unit, just the tank ground through the screws.
Connected ground on gauge to lower side of the dashboard panel.
Started and it appeared to work, the gauge read about ½ tank which was what I had put in. It seemed to be working for the 30 minutes or so I had it running.
Now, when turn on the key, gauge pegs to F as soon as it has power, does not move. Drops to E without power.
Have Tried:
Disconnected sending unit wire at sending unit and still reads F with power, drops to E with no power.
Grounded the sending unit wire to negative cable ground and gauge drops to E with power.
Removed sending unit and held in hand, connected sending unit wire, with power on, still pegs to F even if you move the float and arm.
Connected a secondary ground wire from sending unit cap to negative battery post and now when you move the float, the needle moves on the gauge, but it is reading backwards. Float down when empty reads F on the gauge and float up when full reads E on the gauge.
Reinstalled sending unit and connected secondary ground wire from sending unit screw to negative ground and stays stuck at F.
The float on the new sending unit doesn’t move freely so I think it may be bad, but I have a feeling that even if it was moving, the gauge would still read backwards. When the gauge did work it was ½ full, so no way to know if it would go the correct direction as the gas level lowered.
I read through many of the posts on here about these type issues and I am unsure as to the next step. The float on the new sending unit sure doesn’t move as freely as I think it should, but even if it does and makes the gauge move, how do I get it to read the correct direction?
I saw a post from someone trying to match up ohm rating of the sending unit to a gauge and I wonder if there is an issue with that between these two and also if the resistance on this sending unit is opposite of the gauge, but I can't find a source to get both parts from the same place with assurance they are matched in ohm rating and resistance. I think it should be low resistance is full and high resistance is empty but not sure on that.
Thanks for any help. Newbie to working on tractors so learning as I go and these forums have been incredibly useful!
Replaced old gas tank that did not have a hole for a sending unit with a new one that has a hole. Dash had a hole for a fuel gauge but no fuel gauge.
Ordered new sending unit and fuel gauge.
Spliced into hot wire from key switch ignition to starter button and connected to power terminal of the gauge.
Connected sending unit post to sending unit terminal on gauge. No secondary ground wire from sending unit, just the tank ground through the screws.
Connected ground on gauge to lower side of the dashboard panel.
Started and it appeared to work, the gauge read about ½ tank which was what I had put in. It seemed to be working for the 30 minutes or so I had it running.
Now, when turn on the key, gauge pegs to F as soon as it has power, does not move. Drops to E without power.
Have Tried:
Disconnected sending unit wire at sending unit and still reads F with power, drops to E with no power.
Grounded the sending unit wire to negative cable ground and gauge drops to E with power.
Removed sending unit and held in hand, connected sending unit wire, with power on, still pegs to F even if you move the float and arm.
Connected a secondary ground wire from sending unit cap to negative battery post and now when you move the float, the needle moves on the gauge, but it is reading backwards. Float down when empty reads F on the gauge and float up when full reads E on the gauge.
Reinstalled sending unit and connected secondary ground wire from sending unit screw to negative ground and stays stuck at F.
The float on the new sending unit doesn’t move freely so I think it may be bad, but I have a feeling that even if it was moving, the gauge would still read backwards. When the gauge did work it was ½ full, so no way to know if it would go the correct direction as the gas level lowered.
I read through many of the posts on here about these type issues and I am unsure as to the next step. The float on the new sending unit sure doesn’t move as freely as I think it should, but even if it does and makes the gauge move, how do I get it to read the correct direction?
I saw a post from someone trying to match up ohm rating of the sending unit to a gauge and I wonder if there is an issue with that between these two and also if the resistance on this sending unit is opposite of the gauge, but I can't find a source to get both parts from the same place with assurance they are matched in ohm rating and resistance. I think it should be low resistance is full and high resistance is empty but not sure on that.
Thanks for any help. Newbie to working on tractors so learning as I go and these forums have been incredibly useful!
