M7040 glowplugs

[Tx Jim]

The point that no one has answered, is what is magical about the glowplugs coming on at 32 degrees, and what specially controls that? ALL and every other diesel I've had the glow plugs come on MUCH sooner than that.

I thought I answered that question in my 1st reply to your thread. GP's are controlled by key switch,RELAY & TIMER

 

[suzy]

I thought I answered that question in my 1st reply to your thread. GP's are controlled by key switch,RELAY & TIMER

There must be a thermister there somewhere to turn the glowplugs on at a given temperature. I have one on the block heater of my truck, it is like the ones on heat tapes.

My tractor is maybe a 2010 or close to it. Will look it up somewhere.

 

[the8080]

Looks like no one with the same year tractor as the OP has chimed in. We still don't know if the tractor has a glowplug controller. If the OP could identify which M7040 he has on the Kubota illustrated parts look up, we might be able to sort it out. Or maybe not because some of the parts are serial number specific and say call the dealer.

The newer tractors have controllers per input from their owners and the 2006 WSM shows a preheat position on the ignition switch with no sign of the controller in the electrical schematic or in the write up. The preheat position on the switch is shown in the schematic and mentioned in the writeup.

His glow plug circuit is clearly broken even if it is only the light. My L35 has the controller (16415-65660). Turn the key switch to ON and the glow plug light comes on. The light then goes out and you can hear the relay opening. The controller is hooked to the water temp sensor and that is what determines how long it stays on. When the tractor is warm, it just goes on and right off. The WSM says at -15C it will be on for 5 secs which I would agree with. At 0C I would expect a couple of seconds. At this temp the OP should be able to easily see the light and hear the relay after he turns the key to ON, if there is a working controller in the tractor. On the L35 the controller is behind the instruments with all the relays. You have to take some plastic off the steering column and the big plastic dash housing off to get to it. I think this also gets you to the back of the instrument cluster where the light is.

Take the tractor apart to find out what parts are in it or get the correct model year WSM/parts list.

 

[jcummins]

UPDATE...been to dang cold to work on this...plus some family surgerys...a nephew who was in a serious wreck...haven't done anything on this except, I called the dealer about a month ago. He gave me some things to try, etc...but he agrees, glowplugs are not coming on. He thinks it is probably the relay, but wasn't sure where it was located....couldn't find on his parts list.

The fuse for it is located on the outside of the firewall, along with the headlight relay. I cannot get my hand In There good enough to pop it lose to check it...not just the loader but the loader mount is In the way. Today, got 50+ degrees, so spent some time looking at this again.

Need to locate where the glowplugs relay is at, I suspect it's inside the dash. Tried to take the dash off, and there is something holding it in place at the top, and I can't figure out how to get to whatever is holding it. Question how do you remove that dash? More to the point does anyone know specifically where the glowplugs relay is located?

 

[wmonroe]

I can't help with the location of the glow plug relay, but for getting the dash off, my L has a little phillips screw above the instrument cluster that has to be removed.

 

[jcummins]

I can't help with the location of the glow plug relay, but for getting the dash off, my L has a little phillips screw above the instrument cluster that has to be removed.

You know there is a hole there...and I've poked around in that hole trying to find a screw head...nothing. Because if the steering wheel you cannot see into that hole. So...how far into that hole is the screw...and can you see the screw head?

 

[whis]

glow plugs working or not will not change how it turns over. if it turns slow its battery or to thick oil

 

[jcummins]

Yes....I hate to pay double the price for 5w40...but will probably go with that. I really didn't think with the insulated barn it is in I'd have to do that. ..but appears I do.

BUT glowplugs need fixed.

 

[vrmnthntr]

I can't help with the location of the relay. But my L3540 was turning over very slow when it was below 40 degrees or so. I suspected the battery so I replaced it. New battery did the same thing.

Long story short dealer said the glow plug relay was not sending power to the glow plugs.

I started a thread on it with a video in 6 degree temps. Before it was fixed. I have since started it around 20 degrees and its a night and day difference. No slow turning over. Starts very fast like it should.

 

[jcummins]

I can't help with the location of the relay. But my L3540 was turning over very slow when it was below 40 degrees or so. I suspected the battery so I replaced it. New battery did the same thing.

Long story short dealer said the glow plug relay was not sending power to the glow plugs.

I started a thread on it with a video in 6 degree temps. Before it was fixed. I have since started it around 20 degrees and its a night and day difference. No slow turning over. Starts very fast like it should.

Hmmmm Very good reason to fix the glowplugs before changing oil....which I intend to do.

 

[tom4018]

I have a 2008 M7040, this morning in the upper 20's glow plugs ran 5 or 6 seconds guessing. I run the Rotella 5W-40, started doing that in a Ford I had before and saw better cranking speed in cold weather. Parts manual shows several relays in the dash panel.

 

[wmonroe]

You know there is a hole there...and I've poked around in that hole trying to find a screw head...nothing. Because if the steering wheel you cannot see into that hole. So...how far into that hole is the screw...and can you see the screw head?

On mine the screw head is easily visible, it is a hard area to see and I usually use a stubby screwdriver to get the screw out, but I haven't had trouble getting on the screw. Maybe request a parts diagram from messicks and see if there is a fastner you are missing.

 

[whis]

Big difference in 6 degrees and 20. glow plugs might not be working, but it won't make motor spin faster or slower

 

[jcummins]

Well I called the local dealer, and asked how to get the dash off. He said there is a nut you access on the outside of the firewall. I said, no...I looked, he said look again. Come to find out, there was a small rectangle of mylar tape type stuff stuck on the firewall...same color as firewall, not noticeable. I had to destroy it to get to the nut....then realized the hood has to come off. Just no way to get to it.

With the hood off, I could also get to that 'Charge glow plug' as Kubota calls it on the outside of the firewall...it tested good. I pulled the relays, they are good. Also with the hood off, I could also get to the electrical connect to the glow plugs on top of the motor. Using a test light I found the relays got power at the detent position of the key between the ON and START position. The charge glow plug got power at the START position, also the glow plug connection on top of the motor got power at the START position? I do not understand why no power to at least the charge glow plug at the detent position on the key.

NOW this morning it was 7 degrees and I hoped the insulated barn would be below 32...it was right at 32 degrees. Turned key to ON position, the glow plug light came on for about half a second??.. so those who posted the glow plugs don't come on until 32 degrees are right. The dealer said yesterday that was NOT true, so much for what the dealer knows.

The glow plugs work, but some nagging questions:
WHY 32 degrees when every diesel I've ever had, the glow plugs come on at a much higher temperature? Those that mention this do you have some documentation I could read on it?
WHY does the glow plugs come on so very briefly at 32 degrees when every other diesel the glow plugs cycle for several seconds?
WHY do the glow plugs come on with the key in the ON position this morning, because when I tested when the relay turns on and found it got power at the detent position which is between the ON and START position.
WHY does Kubota's documentation from the WSM manual, shown below, showing the glow plug relay but nothing... nada... about the Charge glow plug as Kubota calls it, which is between the relay and the glow plugs?

 

[jcummins]

BTW my last post wasn't clear on this, but from my testing, it appears the glow plugs come on at any temperature....at the point the engine cranks. No glow plug light coming on.

 

[Tx Jim]

In my M7040 operators manual on page 14 it states:Suppose that the engine coolant temp.is not high enough yet. The glow plug ind.(4) also comes on when the key is turned to on to preheat the engine and goes off automatically when preheat is completed. Illumination time of indicator varies according to the coolant temp. On page 15 it states:If ambient temp is below 0 C(32F) and the engine is very cold activate glow plugs.

 

[jcummins]

In my M7040 operators manual on page 14 it states:Suppose that the engine coolant temp.is not high enough yet. The glow plug ind.(4) also comes on when the key is turned to on to preheat the engine and goes off automatically when preheat is completed. Illumination time of indicator varies according to the coolant temp. On page 15 it states:If ambient temp is below 0 C(32F) and the engine is very cold activate glow plugs.

Thanks TxJim....I actually missed that in the manual. But still...what's magical about 32 degrees when other diesel glow plugs work very different....my ZD326 being one of them. Whether the plugs are working....my testing confirms they are, ....but I'd still like answers to the WHY it works the way it does.

 

[Tx Jim]

I suppose because the engine is direct fuel injected and the engineers thought GP's weren't necessary until at/or below freezing temps. I use my M7040 to feed/load rd bales and I know it starts very easy without the aid of GP's at just above freezing. I have no electricity in tractor shed so this is without the aid of the coolant heater. I've had experience with 2010 D with "INDIRECT fuel injection" and they were hard starters at 60 degrees with GP's activated.

 

[jcummins]

TxJim what oil do you have in your 7040?

 

[Tx Jim]

15W-40 but I live in Texas where most of the time it doesn't get below freezing.