DK45 glow plugs

[seacap04]

My 07 DK45 with 850 hours had not been starting cold as I thought It should. Lots of smoke and not all cylinders firing evenly for a few seconds on start up. It did not seem to matter what the outside temp was. I was thinking that my glow plug circuit was not working as it should and it was time to check it out. I may have to do this in several posts as I live in a rual area and my internet connection is a little flakey.

First step was to determine if the controller and timer were doing their thing. I used an infrared temp probe to see if I any temp at the plugs.

With the FEL and hood on tractor access to the connections is a little difficult. Everything seems to be working to this point so off to shop to remove FEL and hood and check out electrical connections and pull plugs for inspection. A recent thread where an op had plug tip break off prompted me to really want to ck the plugs out for carbon build up.

In the shop, FEL and hood are removed. Now to remove engine related interferance. Coolant tank and fuel filter are unbolted and set aside. Bracket for hood gas cyl is removed. Breather hose is left on for now as I want to really clean the area good. I will be pulling parts that will give dirt internal excess to eng.

I will post this for now and continue with another post.

 

[seacap04]

Ok now to check out electrical connections. I have learned that this tractor is real sensitve to dirty connections. I pull, check, clean, and coat with dielectric compound electrical connections on this tractor far more often than anything else I have ever been associated with. I found 4 glow plug related connections under the hood. If I missed any please post and inform me. I used brake cleaner only because I was out of electrical contact cleaner. I really planned this repair well, didn't I.

So I have found what I believe is causing the problem. Terminal end of glow plug looked just like an old exhaust manifold stud. It was not only rusted, but had the color of being very hot. Probably a high percentage of amps were being consumed at this connection. I knew this connection would not come apart intact, but hit it with PB Blaster and let it soak for a while anyways. Sure enough, hardly any torque twisted the nut off and my nearest dealer is a couple of hours away.

So while I think about what I am going to do about it, I throughly clean area again. Pull breather hose and plug valve cover and manifold. And start to pull glow plugs.

This will take a while to upload so will continue with another post.

 

[seacap04]

I do not have a shop manual. I know I should, but I don't. So to test glow plugs I cleaned up electrical terminal, and attached to each glow plug one at a time. I also made up a wire with spring clip terminal to attach to plug body and bolted it to block. I just turned the key for a second or two and each plug produced smoke at the tip. Be careful as the plugs can get very hot. I never left key on long enough for the body of plug to get more than warm to the touch. I think I now know I have good plugs. I also wanted to ck plugs for carbon build up as another thread involved head removal with a broken plug tip. I had just a light coating of soot after 850 hrs.

Now to address damaged plug. Close exam showed that I still had a thread or two left that I could tighten a nut on. I moved the plug to the front of eng so I had better access for replacement at a latter date. I also stole a new nut from my Satoh. I put a little bit of never sieze on the threads to each plug just to make sure the would not sieze to head. If there is a better way to test the plugs please post and let me know.

I spent about 6 hrs on this repair, but I did other maintainance while I had everything apart and I had some issues that required thinking and gumping. Of course it has now been warm outside, 40's, but tractor starts cold with quick puff of smoke and instantly runs even. I'll have to wait for weather to turn cold and let it sit a day or two to really confirm that I fixed it. Feel good about though. While I was in there I took a couple of pic of items that have been in previous posts that had a lot of disscussion.

I hope this helps anyone who is considering this fix. It is not difficult, just time consuming. If anyone knows a better way to go about this please post. That is what makes this forum great. Have a good day everyone.

 

[k0ua]

Other than some continuity test for the glow plug relay and controller the only tests in the manual are as follows:

The glow plug is installed in the engine cylinder
head.
Glow plugs are heating elements used to warm the air
in the combustion chambers before engine startup.
Current: Max. 20 A of current flows through the glow
plug in 4 seconds after voltage is generated.
Preheating test: The glow plug is normal if its temperature
rises up to 800°C in 4 seconds
after voltage is generated

1.Check and see if the resistance
between the glow plug's ring
terminal and the ground (chassis)
is approx. 0.43 Ω
1. If the measured resistance is
“∞”: open circuit
2. If the measured resistance is
“0”: short circuit
2. Check the voltage when in operation
- With the plug manually preheated,
the voltage between
the glow plug and ground
should be 12 V. (Voltage
fluctuation by operating time:
8~12V)


When the key switch is in "ON" position
The 12 V of power is supplied to the display unit
(BN) through the "ON" terminal (No. 6) and the fuse
8 (unit) by the contact in the key switch (PP). If the
preheat condition of the temperature sensor (below
60 °C) is satisfied, 12 V of power is supplied to
the coil terminal (No. 41) of the preheat relay (BJ)
through the preheat output terminal (No. 41) of the
display unit (BN).
12 V of power is supplied to the glow plug (BM)
through the relay switch contact for 15 seconds.
Simultaneously, 12 V is supplied to the preheat indicator
terminal (No. 45) of the instrument panel assembly
(PT) to turn on the indicator for 8 seconds.

- W hen the key switch is in "ST" position
12 V of power is supplied to the display unit through
the terminal No. 42 of the key switch, and this signal
acts as an indicator of the "start" cycle. This
signal acts as an indicator for the “start” cycle. This
input will shut the preheat cycle down to direct all
battery current to the starter. Once the key switch
returns to the “ON” position, the preheat cycle will
operate again as described in the previous paragraph.
This second cycling of the glow plugs is
known as after heating and cycles for 15 seconds
without illuminating the glow light on the dash

There is also a photo showing where the glow plugs bus is. I would say you are on the right track.. That is definitely a very high resistance connection on that first glow plug as as you pointed out a lot of voltage drop has been occurring there as evidenced by the high heat.

James K0UA

 

[k0ua]

Excellent post by the way with good photo's, this should help many others with this type of problem.. and I am sure the pup would have helped quite a bit if you could have given him a boost up into the engine.

 

[seacap04]

I guess I will have to get a shop manual. Thanks for the info. I was lucky that I was able to confirm controller circuit was working right off the bat. I had power to buss bar confirmed by heat rise. I have alligator clips that side onto my multimeter probes. For some reason this time I was getting high resistance through the probes I did not trust them to give me accurate ohm measurement. Something else to fix in near future.

 

[Coyote machine]

Excellent post and detailed pics with description of your work method, logic used, etc. This judge's rating: 9.75! :thumbsup:

One thing I would note is the grey oil fill cap you show is NOT to be used to fill the crankcase with oil. The orange capped rubber plug at the IP location is what is used to prevent airlock to the crankcase, which can be caused if the upper fill cap is used.
You probably are aware of that already- but others may not be.
BTW, how do you get the text into your pics?

 

[seacap04]

Thanks CM. I should have made a statement about the oil fill cap. You would have to be really determined to get to that cap to put oil through it.

 

[landedakioti]

My 07 DK45 with 850 hours had not been starting cold as I thought It should. Lots of smoke and not all cylinders firing evenly for a few seconds on start up. It did not seem to matter what the outside temp was. I was thinking that my glow plug circuit was not working as it should and it was time to check it out. I may have to do this in several posts as I live in a rual area and my internet connection is a little flakey.

First step was to determine if the controller and timer were doing their thing. I used an infrared temp probe to see if I any temp at the plugs.
<img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=292173"/><img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=292175"/>
With the FEL and hood on tractor access to the connections is a little difficult. Everything seems to be working to this point so off to shop to remove FEL and hood and check out electrical connections and pull plugs for inspection. A recent thread where an op had plug tip break off prompted me to really want to ck the plugs out for carbon build up.
<img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=292177"/>
In the shop, FEL and hood are removed. Now to remove engine related interferance. Coolant tank and fuel filter are unbolted and set aside. Bracket for hood gas cyl is removed. Breather hose is left on for now as I want to really clean the area good. I will be pulling parts that will give dirt internal excess to eng.
<img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=292179"/><img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=292180"/>
I will post this for now and continue with another post.

Seacap04, thanks that will help me out a lot to see if my glow plugs are working right. Will start monday. Today hung lights on the house and took my snowblower a part drained the gas out took the carb a part cleaned everything put it back together and put fresh gas pulled the cord started up on the first pull.

 

[ritcheyvs]

Great post/pics. I envy your shop. WRT testing glow plugs, the only additional things you could have done would be to measure the current and temp. But looks like your plugs are working fine. If any carbon buildup is suspected it's a good idea to clean out the glow plug holes and then crank the engine to blow out any carbon debris. If you have a gun cleaning kit, a bronze bore brush (slightly bigger than the hole) works well for this purpose; just don't unscrew it from the rod while it's in the hole.

Probably not your issue, but My DK45S had a glow/start problem that turned out to be the ignition switch. My switch worked fine in the on/glow position but stopped the glow signal when turned to the crank position. Cleaning/luning the switch fixed that problem.