Bad news big repair

[John_Mc]

I assume that derating occurs when the computer detects a fault. BUT will the computer RERATE if fault is fixed or is it a tech call out once derating occurs.

This is exactly what I was wondering. What happens if you don't disconnect anything, just run an additional line to the glow plugs activated through a momentary contact push button switch (as noted, you'll probably need to run it through an appropriately rated relay, since most switches are not rated for that sort of current). You might even be able to run the alternate power (or alternate ground depending on how it's wired) direct to the existing relay coil. MAYBE the ECU will not be ble to sense this, and things will operate as desired. However, if the ECU gets confused and derates, will it stop derating once you stop manually powering the glow plugs? If so, no big deal. You don't really need maximum power when first starting and warming up your tractor anyway.

 

[Hay Dude]

This is exactly what I was wondering. What happens if you don't disconnect anything, just run an additional line to the glow plugs activated through a momentary contact push button switch (as noted, you'll probably need to run it through an appropriately rated relay, since most switches are not rated for that sort of current). You might even be able to run the alternate power (or alternate ground depending on how it's wired) direct to the existing relay coil. MAYBE the ECU will not be ble to sense this, and things will operate as desired. However, if the ECU gets confused and derates, will it stop derating once you stop manually powering the glow plugs? If so, no big deal. You don't really need maximum power when first starting and warming up your tractor anyway.

Unsure, but those are my exact questions.

 

[groundcover]

Definitely check all the harness connections and grounds, clean up and a dab of dielectric grease. A work around could be put in new glow plugs wired to a momentary switch and relay and leave the old ones hooked up to the ecu. Make them a little box to live in out of the way Under the hood. Should be way cheaper !

 

[K5lwq]

There is no way the ECU would know the glow plugs are disconnected. If there is any feedback to the ECU, and I highly doubt there is, it would have to be a sensor somewhere that is triggered by the heat of the glow plug. If they are wired to work on a new circuit they will produce heat and the ECU will be satisfied.

However we know they are not working now and no light so obviously the ECM is not concerned with the glow plugs.

Edit to add...The glow plugs are disconnected anyway after the relay kicks out. So what difference could it make if they are disconnected after the relay?

 

[Hay Dude]

There is no way the ECU would know the glow plugs are disconnected. If there is any feedback to the ECU, and I highly doubt there is, it would have to be a sensor somewhere that is triggered by the heat of the glow plug. If they are wired to work on a new circuit they will produce heat and the ECU will be satisfied.

However we know they are not working now and no light so obviously the ECM is not concerned with the glow plugs.

But on the other tractor they serviced, the ECU knew the GPs were out and set a code.

 

[K5lwq]

But on the other tractor they serviced, the ECU knew the GPs were out and set a code.

I edited the post. They are disconnected when the relay is no longer energized. That wire can not be the feedback. It is totally separate from the control side of the circuit.

 

[CADplans]

If you have to push a button to energize the glow plugs, hide the button,,
with the button hidden, that will make it MUCH harder to steal the tractor.

 

[not2old]

Correct!
And that’s another really strange thing.…The dealer took a look at what I had already done. I thought maybe they could shed a little more light on the problem, but they didn’t give me much more info.
However, they had an older M125X in with the same problem a few weeks ago. It had No glow plugs, but it DID show a code. They Ohmed everything and tried new sensors- no dice.
They suggested an ECU replacement and $6000 later, the older M125X had glow plugs again.
So the question is, why would the older, but similar size tractor throw a glow plug code, but mine doesn’t?

FYI: My GC2610 doesn't have all this stuff that's giving you problems but it did turn on a light that had no description in the owner's manual. The dealer didn't know so they called the factory. I was told my tractor did not support that light but on some other model it indicated a plugged air filter. I cleaned the air filter and the light went away.

 

[etpm]

There were a lot of posts here so I may have missed something you have already tested. If this is so then I apologize for being redundant. But maybe I didn't miss anything so here goes. Since the ECU cannot power the glowplugs directly it must power a relay. So the first thing to check is if this relay is getting power to the relay coil when the glowplugs are supposed to be energized. If the relay coil is not getting power then check the wires from the relay coil to the ECU. If the wires are OK then check for power right at the ECU. No power right at the ECU? Then maybe it's the ECU. If it is getting power to the relay coil then check power to the relay contacts. If no power to the relay contacts then find the problem in the wires coming from the battery that go to the relay. If there is power to the relay contacts but none coming out then the relay is bad. The relay contacts could be bad or the relay coil could be bad. Make all these checks relating to the relay at the relay. If there is power at the relay output then the problem must lie between the relay and the glowplugs.
If there is no power at the ECU where the wires from the relay go when the glowplugs should be energized then the problem is partly or wholly in the ECU. It is possible, though unlikely, that the ECU monitors the glowplugs even when they are not energized. To check this remove the wires from the glowplugs and run the tractor. If it runs the same as before then the best work around is to then leave the wires disconnected and wire in a relay and push button switch, as was mentioned previously. If the tractor does constantly monitor the glowplugs there is another work around, also involving a relay or two, that will energize the glowplugs while isolating the ECU during starting, but will restore the ECU back into the circuit once the glowplugs are de-energized. If need be I will draw up the fairly simple circuit and post it.
Eric

 

[jyoutz]

A heated garage option available?

Or a block heater?