GloPlugs

elimsprint

Member

Equipment
Kubota Sunshine ZL1-235 with tiller, FEL and 60" box blade
Feb 23, 2023
42
5
8
Kelowna, BC, Canada
The glo plug light on my ZL1-235 dash never goes out and 12v goes to the plugs constantly. They are all burnt out because of this so I want to fix the problem before I replace them.
I thought maybe it was controlled by the engine temp but I have fixed all the cooling problems on my ZL1-235 and now the temp gauge works and everything seems good but the glo plug light is still on and they are still getting voltage so that wasn't the cure.
I have a wiring diagram but it's all in Japanese so I can't really tell what controls the plugs getting power. There is no special glo plug spot on the ignition switch, only off/on/(start? as the writing is in Japanese on the spring return part of the switch). Without cutting all the wiring looms apart I can't follow where the glo plug power wire is coming from so what I was thinking I would do is place a momentary push button switch and a relay to control power getting to the plugs and just use that. Is that OK to do as a fix?
I've never had a diesel before so how long would I need to push the button for before starting the engine in cold weather? It starts easily now when it's warm out. The previous owner heated the intake manifold with a torch but that is a pita and I want to do it using the plugs.
 

Russell King

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L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
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Your general concept is correct and can be done. You will need to insulate the existing wiring to the glow plugs from whatever is providing the power so they won’t get grounded and cause problems.

You may need to use a resistor to drop the power. On my L185 there is a indicator that drops the voltage when in glow plug position. The starter drops the power when cranking so the wiring bypasses the indicator.

Your concept is battery to relay, relay to glow plugs. You will need to use heavy gauge wire for that and a robust relay. The fire wire will provide power from the push button. You can determine how long to hold it down but probably 15 to 30 seconds when cold and 10 to 15 seconds when cold. Since you are in really cold weather you may have to increase the times during really cold weather or if you’re having trouble starting it
 

North Idaho Wolfman

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Glow plugs need two feeds, one from the preheat position and one from the crank position.
 

Roadworthy

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Many older tractors had no glow plug controller. They did have the glow indicator which was supposed to light when the key switch energized the glow plugs. It served to drop the voltage from the nominal twelve volts to about 10.5 volts which the glow plugs were rated for. When the glow plug position failed on my Mitsubishi tractor I went to a fifty amp rated spring loaded toggle switch from the auto parts store. This was simpler than a relay. I had tried a push button but my thumb got sore. The toggle switch had more leverage. You can still get the voltage dropping resistors from eBay or the like but they take a pretty big hole in your dash.
 

elimsprint

Member

Equipment
Kubota Sunshine ZL1-235 with tiller, FEL and 60" box blade
Feb 23, 2023
42
5
8
Kelowna, BC, Canada
Your general concept is correct and can be done. You will need to insulate the existing wiring to the glow plugs from whatever is providing the power so they won’t get grounded and cause problems.

You may need to use a resistor to drop the power. On my L185 there is a indicator that drops the voltage when in glow plug position. The starter drops the power when cranking so the wiring bypasses the indicator.

Your concept is battery to relay, relay to glow plugs. You will need to use heavy gauge wire for that and a robust relay. The fire wire will provide power from the push button. You can determine how long to hold it down but probably 15 to 30 seconds when cold and 10 to 15 seconds when cold. Since you are in really cold weather you may have to increase the times during really cold weather or if you’re having trouble starting it
I was actually just going to splice the relay into the existing glo plug wire right near the glo plugs. It looks to be 12g or so and I was just going to splice a 40A relay I have lying around in to it so I would keep whatever power they were using to the glo plugs the same and just use a random 12v source for the relay activation power. Would that work OK?
 

elimsprint

Member

Equipment
Kubota Sunshine ZL1-235 with tiller, FEL and 60" box blade
Feb 23, 2023
42
5
8
Kelowna, BC, Canada
Glow plugs need two feeds, one from the preheat position and one from the crank position.
I only have one wire going to them and I was just going to splice the relay into that wire and use a random 12v source and a switch to activate the relay when needed. Would that not keep my voltages and feeds correct?
 

elimsprint

Member

Equipment
Kubota Sunshine ZL1-235 with tiller, FEL and 60" box blade
Feb 23, 2023
42
5
8
Kelowna, BC, Canada
Many older tractors had no glow plug controller. They did have the glow indicator which was supposed to light when the key switch energized the glow plugs. It served to drop the voltage from the nominal twelve volts to about 10.5 volts which the glow plugs were rated for. When the glow plug position failed on my Mitsubishi tractor I went to a fifty amp rated spring loaded toggle switch from the auto parts store. This was simpler than a relay. I had tried a push button but my thumb got sore. The toggle switch had more leverage. You can still get the voltage dropping resistors from eBay or the like but they take a pretty big hole in your dash.
I did think of using just a switch but as I have a useable relay lying around I thought I would just use that. I do have some toggle switches laying around also but I thought I would inevitably bump it on accidentally so that was why I was opting for the push button which wouldn't have to be very stiff as I would only need a very low amperage one to activate the relay.
 

elimsprint

Member

Equipment
Kubota Sunshine ZL1-235 with tiller, FEL and 60" box blade
Feb 23, 2023
42
5
8
Kelowna, BC, Canada
The strangest thing happened today. I took the hood off the tractor to remove a glow plug and get the numbers off it to order new ones. I also wanted another look at the power lead to see where to splice it. I noticed that there was a plug on the wire a few inches past where I could see easily so I thought I would unplug it and see if I could get a matching plug set which would make splicing into it really easy.
Before I did that I thought I might as well check the voltage to the lead so I turned the key (ignition) switch ON and got an 11v reading at the plugs. The glow plug light on the dash was on.

I then unplugged the glow plug lead and disconnected it from the glow plugs. The plug on the lead was quite dirty so I blew it out with compressed air and put some dielectric grease on it and reconnected it to see how it would go back together, all good. I then thought I would check the voltage just to make sure I had a good connection so I hooked up the voltmeter to the end of the lead (not connected to the glow plugs now) and I turned the key on and...... I got a little flash of voltage on the meter and then nothing. The glow plug light on the dash lit up for a second and then it went out at the same time. I checked the plug on the lead that I had just cleaned and lubed and tried again. This time nothing at all! What?????

I fiddled around some and still no light, no power. Checked the fuses, all good. I then tried turning the key to the START position without depressing the clutch and I got power to the glow plug lead and the glow plug indicator on the dash lit up. Go back to the ON position and the glow plug lights and power go out. That's new. Turn the key to the START position again, light on and power to the lead again. I push in the clutch and the motor starts so I let the key return to the ON position and the light on the dash goes out and the power to the glow plugs cuts off. Huh! While the motors running in neutral, clutch out, I tried the key to the START position again, no starter grind, no power to the glow plugs and no indicator light. Progress?

Does this starting sequence seem reasonable? Key to spring loaded START position to heat the glow plugs, then depress clutch to engage starter and start motor then release the key so it returns to ON position and then let the clutch out if in neutral.

Could I have released a stuck relay when I tried to read the voltage with the power lead off the plugs? I've never done that before, I always just took readings with it attached to the dead plugs.
 

elimsprint

Member

Equipment
Kubota Sunshine ZL1-235 with tiller, FEL and 60" box blade
Feb 23, 2023
42
5
8
Kelowna, BC, Canada
And now for my new problem, I can't seem to match up the numbers I got off the glow plug to anything. On one side of the hex head it is stamped NGK, 1713R over 11V on another and 9011 on another. Any way I google those numbers I either get spark plugs or nothing at all. I emailed NGK Canada to see what they know but I have yet to hear back. Any input from the brain-trust here?
 
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North Idaho Wolfman

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
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Sandpoint, ID
I only have one wire going to them and I was just going to splice the relay into that wire and use a random 12v source and a switch to activate the relay when needed. Would that not keep my voltages and feeds correct?
In the wiring before it becomes one wire there are 2 feeds one feed in the pre heat and one feed in the crank.
Believe me or not, but it won't start properly if you only heat them in preheat.

KUBOTA 15521-65510
NGK NGK Y-106V
 
Last edited:

elimsprint

Member

Equipment
Kubota Sunshine ZL1-235 with tiller, FEL and 60" box blade
Feb 23, 2023
42
5
8
Kelowna, BC, Canada
In the wiring before it becomes one wire there are 2 feeds one feed in the pre heat and one feed in the crank.
Believe me or not, but it won't start properly if you only heat them in preheat.

KUBOTA 15521-65510
NGK NGK Y-106V
I believe you, I know nothing about diesels other than semi motors and that's only to start them before I drove them and we always plugged the block heaters in in the winter so they were easy to start.

Does my starting sequence as listed in post #8 seem right to you? Using the key to power glow plugs and clutch to start?

Thanks for the part numbers, I will check them out.
 

Russell King

Well-known member

Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
4,655
994
113
Austin, Texas
Okay you may want to post some pictures of the dash and glow plug wiring so we might be able to see what you have on the tractor.

Just to describe how my similar vintage L185 is set up for glow plug and starter operation:
power from battery goes to a main power key switch that can be on or off (or to provide power to the headlights). That key switch provides power to a secondary switch that can be turned to the left for glow plug operation (only). In that position the wire then feeds through a indicator that is also a resistor and drops the voltage from 12 to something like 10.5 volts. Then that goes to the tops of both glow plugs. The bottom of the glow plugs are grounded into the block and the internal glow plug wiring is heated by the power applied. When the clutch is depressed (safe switch closed) the starter will spin when the secondary switch is turned to the right. In that position the wire from the switch bypasses the glow plug indicator but is connected directly to the wire g from the indicator to the glow plug. Because this also activates the starter, the battery voltage is lower than 12 volts. You also only hold the starter on for a short time before the engine starts or you aba don the cranking and remove power to the glow plugs.

In your case and mine also I can turn the switch to the crank position and NOT have the clutch depressed (safety switch open). This will provide power to the glow plugs but it will be at 12 volts and not the reduced voltage as normal. It will work but would shorten the life of the glow plugs. I also have read that the glow plug tips “explode“ if they get too hot and then you have ceramic bits in your cylinders that can cause damage.

I guess you could run the wiring through a indicator/resistor when in the starting position but when actually starting the voltage would be lower and the glow plugs might not be hot enough to cause the tractor to start running.

I think it might be best to figure out how the wiring is supposed to work and return it to original. If there is some glow plug controller that is broken then that may be impossible or cost prohibitive to do. If that ends up being the case then you can use your original plan and possibly a second switch to power the glow plugs when cranking (bypass the resistor).

Please let us know if your key switch and wiring are still in factory original condition or if it has been modified over time.
 

Roadworthy

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L2501 HST
Aug 17, 2019
1,649
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113
Benton City, WA
I had a Mitsubishi tractor. I bought it used and it had the wrong glow plugs. I was told the correct glow plug number by a long time Mitsubishi guy. I contacted NGK and sure enough, they came up with the same number he had given me. NGK is a really good information source but may take a day or two to get back to you.
 

North Idaho Wolfman

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Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
28,605
5,066
113
Sandpoint, ID
I believe you, I know nothing about diesels other than semi motors and that's only to start them before I drove them and we always plugged the block heaters in in the winter so they were easy to start.

Does my starting sequence as listed in post #8 seem right to you? Using the key to power glow plugs and clutch to start?

Thanks for the part numbers, I will check them out.
I would replace all the glow plugs then try the start sequence the way you described and see what you get.
 

elimsprint

Member

Equipment
Kubota Sunshine ZL1-235 with tiller, FEL and 60" box blade
Feb 23, 2023
42
5
8
Kelowna, BC, Canada
Glow plugs ordered, under hood is just one wire coming from the wiring loom going to the middle glow plug with a metal bar joining the other 2, no pic as I have to take the hood off to see anything and it's a total PITA
Tractor dash with key ON but motor not running, glow plug light second from left and lit again.


Key, 3 positions, OFF, ON and spring return whatever. Lights above with turn signals
 
Last edited:

Russell King

Well-known member

Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
4,655
994
113
Austin, Texas
Your tractor is much more modern than my L185 so I won’t be much help really.

Have you ever had any of the characters translated into English. If you have a smartphone there are ways to get the image of the Japanese into English. This is the way to do it on an Iphone

 

elimsprint

Member

Equipment
Kubota Sunshine ZL1-235 with tiller, FEL and 60" box blade
Feb 23, 2023
42
5
8
Kelowna, BC, Canada
Your tractor is much more modern than my L185 so I won’t be much help really.

Have you ever had any of the characters translated into English. If you have a smartphone there are ways to get the image of the Japanese into English. This is the way to do it on an Iphone

I tried that on the Japanese manual I have and couldn't get it to work but I am not very techno literate. I'll try it on the switch writing and see what happens.
 

Russell King

Well-known member

Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
4,655
994
113
Austin, Texas
I tried that on the Japanese manual I have and couldn't get it to work but I am not very techno literate. I'll try it on the switch writing and see what happens.
No expert on smart phones but you can do it through google translate also. This seems to cover that process

I did it today with the iPhone translate app. Search for that on the iPhone and start the app. Select the two languages you want (Japanese and English). Then at the bottom is a camera symbol that then takes a picture of the character and then you can touch that image to see the translation.

I was Spanish to English and did only one word in the photo and it worked fine. You may have to zoom in on just a few characters and then write down the translation character by character, I have not done Japanese or Chinese so wI’ll try that this weekend to see what happens.
 

elimsprint

Member

Equipment
Kubota Sunshine ZL1-235 with tiller, FEL and 60" box blade
Feb 23, 2023
42
5
8
Kelowna, BC, Canada
No expert on smart phones but you can do it through google translate also. This seems to cover that process

I did it today with the iPhone translate app. Search for that on the iPhone and start the app. Select the two languages you want (Japanese and English). Then at the bottom is a camera symbol that then takes a picture of the character and then you can touch that image to see the translation.

I was Spanish to English and did only one word in the photo and it worked fine. You may have to zoom in on just a few characters and then write down the translation character by character, I have not done Japanese or Chinese so wI’ll try that this weekend to see what happens.
I had to install and uninstall Translate 3 times but now it seems to be working, thank you!
I will try it tomorrow on the tractor and play with it tonight with the manual and report back soon.
 

elimsprint

Member

Equipment
Kubota Sunshine ZL1-235 with tiller, FEL and 60" box blade
Feb 23, 2023
42
5
8
Kelowna, BC, Canada
Sorry for leaving this conversation with no notice but between the forest fires, a couple too close for comfort, and now this, see below, I've been kind of tied up. I did wire the glow plugs directly to a relay powered by my already there horn button, horn didn't work anyways, and in testing it does seem to work. Turn key to ON and hold horn button for 10-15 seconds, depress clutch and turn key to start. I also mistakenly posted this in another thread a while ago, my bad!