Bad news big repair

[joea99]

The ECU reads the air and water temp sensors and they are both part of the glow plug wiring circuit and it has been stated that if the relays are bypassed, the tractor derates itself.
So how do you bypass all that and “simply install a switch”?

So, don't bypass them. Leave them in place, just disconnect the "last inch" that puts power to the glow plugs. Probably just a "buss bar" connects them all together and one end goes to the "magic box".

Then connect your own power to the plugs, as others have said, heat and crank.

BTW, who "has stated" it de-rates itself? Kubota or is that an "urban legend"?

 

[Laser Man]

Purchased my M135X in warmer months almost 3 years ago (April 2019). Never thought to see if the glow plugs worked. They actually won’t work if it’s over 41*.
Last winter, I realized the glow plugs weren’t working. Ohmed out wires, looked at wiring for mice damage, water damage, bad grounds, etc. Ohmed out wiring. Thats when I learned the glow plug system in larger kubotas is more complex than I thought. All 4 glow plugs passed electrical testing.
The glow plugs have 2 sensors one for air temp, one for water temp. The ignition switch is also part of the circuit. Then there are 2 relays and a fuse. All of this is controlled by the ECU. Last winter, I replaced
Key switch
water temp sensor
air temp sensor
both relays
fuse

Still no glow plugs. With nothing left to replace or test, I succumbed to a very reputable Kubota dealer. They basically did all the same things I did and replaced one of the new sensors I had already placed.
Still nothing. They called Kubotas double secret probation hotline and Kubota thinks it’s the ECU.

ECU price $6000
ECU Not returnable and no guarantee it will fix glow plugs.

So I’m out of answers. Any thoughts on other possible avenues to pursue

How about a block heater

 

[jgoodma1]

I don’t think it’s that simple, but yes, the thought crossed my mind. They make timer switches too, so you can’t accidentally leave them on.
The sensors must stay in place. We tried to bypass the sensors and if you bypass them, the engine runs de-rated.

I'm no mechanic, but FYI, I had a little John Deere 670 and the ignition switch rotated both directions. I'd rotate the key to the left for 10 seconds or so to warm the glow plugs then rotate to the right to activate the starter motor. That system worked great. Seems that the suggestions being made about a simple switch to activate the glow plugs would work the same way.

 

[MossRoad]

Maybe his chain isn't sharpened correctly.

 

[prairiegirl]

Purchased my M135X in warmer months almost 3 years ago (April 2019). Never thought to see if the glow plugs worked. They actually won’t work if it’s over 41*.
Last winter, I realized the glow plugs weren’t working. Ohmed out wires, looked at wiring for mice damage, water damage, bad grounds, etc. Ohmed out wiring. Thats when I learned the glow plug system in larger kubotas is more complex than I thought. All 4 glow plugs passed electrical testing.
The glow plugs have 2 sensors one for air temp, one for water temp. The ignition switch is also part of the circuit. Then there are 2 relays and a fuse. All of this is controlled by the ECU. Last winter, I replaced
Key switch
water temp sensor
air temp sensor
both relays
fuse

Still no glow plugs. With nothing left to replace or test, I succumbed to a very reputable Kubota dealer. They basically did all the same things I did and replaced one of the new sensors I had already placed.
Still nothing. They called Kubotas double secret probation hotline and Kubota thinks it’s the ECU.

ECU price $6000
ECU Not returnable and no guarantee it will fix glow plugs.

So I’m out of answers. Any thoughts on other possible avenues to pursue?

Keep the $6000 and build a heated shed with it maybe.

 

[thorn]

My late dad was an electrical engineer and learned to fix radios while he in the Navy during WW2 as a radioman (Morse code and tube radios back then). He continued to fix ours, relatives and friends electronics. In later years he was having a hard time finding ICs, they would probably have a production run and stop. After a few years they were impossible to find. They also started surface soldering components so it took more time to de-solder and re-solder. I wonder if one might have a hard time finding some IC components on older ECUs.?

After reading this thread, I have noticed my 2008 JD5525 has been harder to start in colder weather the last couple of years, lots of smoke and runs rough for a minute. When It's really cold I plug it in and it starts like its in the 90sF like summer.

 

[Skystream]

It's a 3 year old tractor, insist on getting the Kubota service representative involved. They have discretionary funds available for out of warranty repairs.

 

[ptsg]

It's a 3 year old tractor, insist on getting the Kubota service representative involved. They have discretionary funds available for out of warranty repairs.

The M135X was produced between 2009 and 2014, accordingly to TractorData. Definitely not a 3 year old tractor.

 

[5030]

I believe he's hosed far as any coverage for a defective part.

 

[geneP]

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