TN55 won't turn off!

[Kregan87]

Hey, new here. I've searched around a bit and haven't found the exact situation I have. Had an intermittent problem for a year or so of my 2000 NH TN55 not shutting off with ignition. So I replaced the ignition switch the first time and just by coincidence it worked for about 6 months. Then started acting up again. I ordered a new fuel shutoff solenoid which on this tractor gets power from ignition and open up flow of fuel. When ignition is shutoff the solenoid looses power and the plungers falls closing the path for the fuel. Well I replaced the solenoid and no change. I can remove 12v power from solenoid all together and it doesn't shut tractor off. Could it be the passage the plunger falls into in the injector pump is dirty or clogged preventing it from falling into place? Any ideas I would really appreciate it!

 

[Kregan87]

Also forgot to mention. If I disconnect the wire from the solenoid and check continuity there it continuity between the post on the solenoid and ground. Continuity between the body of the solenoid and ground makes sense but not the post where the 12v attach. Could this prevent it from working correctly?

 

[TractorTech]

Welcome to TBN. Odd indeed. Continuity on the shutoff? It is a coil and it will have some continuity with resistance. A multimeter would show this, a test light will not. What are you testing continuity with?
As far as the shutoff goes, whether it is working or not, it should shutoff fuel in the pump. Your thought that something is in the passage is about the only thing that would keep fuel flowing under the plunger seat. It could be a piece of the old plunger.