New Holland Boomer 54D Tractor Error Code

[UncleMerle]

I have an intermittent problem where error code 3350 appears as the instrument cluster is trying to excite the alternator over the period of half a minute or longer. The service manual describes the fault related to the error code as "terminal 50 (crank input) always on", and "engine cranked for too long, or key switch failure". My key switch seems to be operating correctly, and the tractor engine starts almost immediately, but it can take several seconds to a minute or so to excite the alternator. The weird thing is that if it takes longer than about 30 seconds (+/-) to excite the alternator, the 3350 error code appears even though the engine is running - not cranking. If the alternator excites in less than 30 seconds of run time, the 3350 error code does not appear. Why is this happening? Isn't the state of the alternator / charging voltage unrelated to the cranking circuitry, and doesn't this error code coming on when it does indicate some other kind of problem? My dealer went through the guided troubleshooting procedure for the 3350 code but did not find anything. I am hoping someone here has the experience or the expertise to suggest what it is that is causing the error code and what should be done to resolve it.

 

[RjCorazza]

Hazarding a guess, the computer is receiving a low voltage reading (terminal 50) and it's assuming that the engine is cranking for the extended period. A voltage reading on the battery at rest, then when running would be good to know, both immediately after starting, and after the voltage comes up to normal... If that's what you're experiencing.
Sure sounds like something is wrong with the alternator or belt, but I'm no expert. My tractor won't produce voltage after starting until the engine rpm's are bumped up to 1200 or so. If I start it and just keep it at low idle (700 rpm) the tractor electronics see less than 12.4v or so.

Hope you get it figured out!

 

[UncleMerle]

Hazarding a guess, the computer is receiving a low voltage reading (terminal 50) and it's assuming that the engine is cranking for the extended period. A voltage reading on the battery at rest, then when running would be good to know, both immediately after starting, and after the voltage comes up to normal... If that's what you're experiencing.
Sure sounds like something is wrong with the alternator or belt, but I'm no expert. My tractor won't produce voltage after starting until the engine rpm's are bumped up to 1200 or so. If I start it and just keep it at low idle (700 rpm) the tractor electronics see less than 12.4v or so.

Hope you get it figured out!

Great insight - thanks for your suggestion. I bought this tractor used in October and didn't discover it had this issue until I got it home. Since then, I have replaced the battery, alternator, and drive belt, but it hasn't made a difference. The charging voltage immediately after start-up is approximately 11 to 12V. Once the voltage jumps up, it is in the area of 14.3 to 14.5V. But you've got me thinking about the throttle position when I start the tractor. Because I typically throttle down before shutting it off, I think there is a good possibility that I have been starting it at idle speed, which would contribute to the situation you described. I am going check this out first thing in the morning. I will let you know what happens. Thanks for your input.

 

[UncleMerle]

Giving some throttle at start-up did not make a difference. I should have anticipated this, but in my excitement to try a simple solution, I overlooked the fact that the instrument cluster is responsible for exciting the alternator for the first minute of run time. After that, increasing the engine speed to 2300 RPM should enable the alternator to self-excite, but that process seems to have no effect. The voltage comes up when it's good and ready and not before. AAAAGGGGHHHH

 

[RjCorazza]

I know very little about alternators. I mistakenly assumed they were all self exciting, but after a short read it appears they are excited through the battery lamp in the instrument cluster (?).
Other than the standard troubleshooting steps of ensuring a charged battery, good connections, etc, I got nothin.

Hopefully someone more knowledgeable will chime in...