Bad news big repair

[Hay Dude]

Oh, there is your problem with the glow plugs... You're missing the battery!

Heres the ECU. Checked connections for moisture or corrosion. That looked ok. There was some, but not enough for alarm. Moving to check a few other things tomorrow

 

[LittleBill21]

start at the relay.... it will tell you which way to head.

 

[Hay Dude]

start at the relay.... it will tell you which way to head.

Yeah I already did all that. Last thing was to check the ECU plug/harness for anything. It looks good.
Gotta be cold for plugs to operate. 54* today.

 

[coobie]

I hope you win Hay dude stay after it.

 

[dirttoys]

Something a lot of folks have to remember is that the OP actually WORKS!!! He posted questions on Saturday and by Sunday people were asking him why he hadn't fixed it yet. Sheesh. He had other stuff to do. Make your suggestions and then move along. I'm sure he'll post his results when he has time to attempt repairs... or install a block heater.

LOL, I have followed this, biting my tongue, for what seems like a year. Glad I didn't say anything

On the good side, it is neat to see how many people try and help.

Best,

ed

 

[Hay Dude]

I hope you win Hay dude stay after it.

Thanks friend.
It’s finally back to a garage. We spread until it rained over the weekend. Ground too muddy to spread, so I have a little time to mess with it in an unheated garage.

 

[DieselBound]

Look real close at every connector in those harnesses (if you knew which wire then one could concentrate on just that one, but...). Further, examine each wire within an inch or so of the connector. I had my cabin fan stop working on my NX a couple of summers ago (right in the middle of a hot day and with a lot of mowing to do; AND, with mouse stench permeating the cabin! [I suspected that mice might have chewed wires but that turned out not to be the case]). I troubleshot the holy heck out of it and just couldn't figure out why the fan wasn't working. While scratching my head and wondering what the next step was I was kind of desperate and had the fan powered up and then started wiggling wires (and burning incense). Lo and behold, the squirrel cage on the fan started spinning! It was a bad wire, a factory defect! At the factory someone bent the wire (within 1/2" of the connector) such that it broke enough strands in the wire to work for a few years and then decide to stop working. The wire didn't look like it was a problem, just had a definite short bend in it. And for some reason when I disconnected the connector and probed it for power it showed that it was fine!

I would also look closely at the wires as they go into/out of the relay(s): I'm thinking that this would be the most likely place for such an occurrence ass the wire bundles to the ECU tend to be handled more gingerly (the group of wires together tend to kind of protect the individual wires).

Here's what the wires to my cabin fan looked like (not real obvious [I replaced the connector, that's why the wires are cut- no wiseguy cracks! ]):

 

[Hay Dude]

Diesel Bound, I will keep checking. It’s tedious and it pretty much requires two people and it to be cold for them to actually work. Yes you can look at wires relays, etc alone in a warm shop, but the OEM glow plugs won’t work unless it’s cold. You also need a second person to keep the switch in the GP position to perform some of the tests.
Takes away from time at work for 1-2 people. Time is something which I have little of.

 

[DieselBound]

My shop isn't heated. I do plenty when it's not warm out. Before I got our shop I'd worked on everything outdoors and on uneven rocky surfaces: I did the first timing belt on my car in winter, with a canopy over the front part of the car- did that when I was in my mid 50s. I'm a tyrant, in which case I force myself to just deal with crap! But yeah, when it takes another person to assist then that makes it really tough.

Wondering if anyone has any ideas for how to set up something such that you don't need another person. A remote triggering device of some sort: my brain isn't working well enough for me to come up with something right now).

 

[groundcover]

Clean up all your grounding spots too, a poor ground can do strange things !

Not what we're looking for here but a solution I have seen for this type of problem was to put a tee in the heater hoses with a valve and quick couplers and a matching set up in a work truck. Farmer or logger pulls up, hooks up and circulates the hot coolant from the pickup through the cold diesel, drink a cup of coffee and fires up the grumpy diesel.
I always thought it would shock the cold block having that hot coolant hit it but have seen it done for years.

 

[MossRoad]

Thanks for adding some sanity.
you can post questions or replies while wrenching, working, eating, etc.
Just like I did today.

Yep. At my job current job sometimes I have to watch glue dry! Seriously.
Watch
Glue
Dry
Yikes.

So get out the phone and see what's up with the world.

I have other tasks where I have to wait 5-10 minutes at a time. Like if I have to do a repair in an occupied space, but have to wait for it to be unoccupied. You have to stand and wait. Nothing else to do. 5 more years of that and I retire again.

 

[milkman636]

It seems odd that only one function is failing if the ECU is bad. I’m more inclined to think that the ECU is not getting all the necessary inputs needed to determine that the glow plugs should cycle. Temp sensors are typically resistive inputs, they should have a linear change in resistive value over a specific temperature range. Sensor manufacturers typically offer a chart that lists proper resistance values for given temperatures. Does the service manual cover checking the temperature sensors for accuracy of the temperature inputs? Is there any kind of summary in the service manual that lists all the inputs into the glow plug cycling decision? Does the manual have any diagrams that detail the glow plug circuits? Or whether or not there is wiring connected in parallel that could monitor glow plug circuit integrity?

I like making things work as designed too. If I lived anywhere nearby I’d stop in and offer a hand. I’m sure there are others here that would be willing to help also. Not having a similar tractor or access to relevant manual sections does limit our usefulness though.

 

[MossRoad]

Clean up all your grounding spots too, a poor ground can do strange things !

Not what we're looking for here but a solution I have seen for this type of problem was to put a tee in the heater hoses with a valve and quick couplers and a matching set up in a work truck. Farmer or logger pulls up, hooks up and circulates the hot coolant from the pickup through the cold diesel, drink a cup of coffee and fires up the grumpy diesel.
I always thought it would shock the cold block having that hot coolant hit it but have seen it done for years.

Wow! That's beautiful. Never heard of that before.

 

[MossRoad]

It seems odd that only one function is failing if the ECU is bad. I’m more inclined to think that the ECU is not getting all the necessary inputs needed to determine that the glow plugs should cycle. Temp sensors are typically resistive inputs, they should have a linear change in resistive value over a specific temperature range. Sensor manufacturers typically offer a chart that lists proper resistance values for given temperatures. Does the service manual cover checking the temperature sensors for accuracy of the temperature inputs? Is there any kind of summary in the service manual that lists all the inputs into the glow plug cycling decision? Does the manual have any diagrams that detail the glow plug circuits? Or whether or not there is wiring connected in parallel that could monitor glow plug circuit integrity?

I like making things work as designed too. If I lived anywhere nearby I’d stop in and offer a hand. I’m sure there are others here that would be willing to help also. Not having a similar tractor or access to relevant manual sections does limit our usefulness though.

Well, think about it. Each function is controlled by different sections on the ECM. If one component fails in a section, the rest of it can continue to operate.

 

[number two]

Clean up all your grounding spots too, a poor ground can do strange things !

Not what we're looking for here but a solution I have seen for this type of problem was to put a tee in the heater hoses with a valve and quick couplers and a matching set up in a work truck. Farmer or logger pulls up, hooks up and circulates the hot coolant from the pickup through the cold diesel, drink a cup of coffee and fires up the grumpy diesel.
I always thought it would shock the cold block having that hot coolant hit it but have seen it done for years.

I had thought about posting the same idea since I've seen loggers doing this 15-20 years ago.
Too bad so many posters have not really read the issue and inject the same ideas over and over.

 

[MHarryE]

This might be really stupid -I’m prepared for that. When I had one, I kind of remember part of the priming procedure was to disconnect the glow plug at the front , in front of cooling system up high. Reason not to toast the glow plugs during the multiple switch on 30 seconds, off 30 seconds, etc. my manual went with the tractor 5 years ago when I traded. Not sure if it was disconnect at relay or 60 amp slow blow fuse. I’m sure it’s stupid because you already changed that out but it rang a bell with me that I screwed something up going through this procedure. But I think there is a w/y wire out of the ECM that feeds the relay. Need battery voltage from there when cold, if no voltage then it’s ECM or temp sending unit and I think you already changed all the easy stuff. The jury rig is easy but I’m with you - would want it to work like intended just like your 126.

 

[Racenut]

Glow plugs wont heat if it's not cold enough.. do you know where the temp sensor is that determines that? a) is the temp sensor working? b) use a freeze spray to cool it off so you can diagnose on your schedule instead of mother nature's. Freeze spray can be canned air held upside down, brake cleaner might even get it cold enough.

 

[Hay Dude]

I’m going to try a little more today. I have some help for a few hours. Then I gotta get back to making some money.

 

[Hay Dude]

It seems odd that only one function is failing if the ECU is bad. I’m more inclined to think that the ECU is not getting all the necessary inputs needed to determine that the glow plugs should cycle. Temp sensors are typically resistive inputs, they should have a linear change in resistive value over a specific temperature range. Sensor manufacturers typically offer a chart that lists proper resistance values for given temperatures. Does the service manual cover checking the temperature sensors for accuracy of the temperature inputs? Is there any kind of summary in the service manual that lists all the inputs into the glow plug cycling decision? Does the manual have any diagrams that detail the glow plug circuits? Or whether or not there is wiring connected in parallel that could monitor glow plug circuit integrity?

I like making things work as designed too. If I lived anywhere nearby I’d stop in and offer a hand. I’m sure there are others here that would be willing to help also. Not having a similar tractor or access to relevant manual sections does limit our usefulness though.

It may not be. And it is of concern to me.
The glow plug issue is ”old”. At least 2 years old and could be as much as 10.
A new issue, just a few month old, possibly related, is my small side display keeps blowing fuses. It’s frustrating because it digitally displays the tractors RPM. Great for PTO usage of round baler, rake, tedder, bush hogs.
It now blows a fuse quickly. Sometimes it takes a day, sometimes a second.
Related to GP issue? I don’t know.
Remember, “I’m only doing this for drama”, so don’t give it much thought.

 

[K5lwq]

It may not be. And it is of concern to me.
The glow plug issue is ”old”. At least 2 years old and could be as much as 10.
A new issue, just a few month old, possibly related, is my small side display keeps blowing fuses. It’s frustrating because it digitally displays the tractors RPM. Great for PTO usage of round baler, rake, tedder, bush hogs.
It now blows a fuse quickly. Sometimes it takes a day, sometimes a second.
Related to GP issue? I don’t know.
Remember, “I’m only doing this for drama”, so don’t give it much thought.

Hey maybe you could replace the fuse with a push button and another fuse. That way you can push the button take a reading and release before the fuse blows.