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Discussion Starter #1
Hi Folks! New to the forum but have search your forum and found lots of help in the past!

Hoping to get some assistance with my 94 John Deere 445. Over the past few years it’s idle quality has decreased and now at WOT I can hear an intermittent miss-fire. I discovered the oil to way overfill (about 3/4” over the full dipstick mark) . While draining it it’s definitely badly fuel diluted.

It will run and mow eh “okay” but when you throttle it it will throw black smoke. Certainly over fueling for one reason or another

I have confirmed the left side cylinder to be a little weaker then the right as far as comparing engine rpm when removing spark plug leads. I understand this is normal due to intake design but its definitely intensifying the issue. I have swapped coils from side to side to rule out a coil issue. No beans.

I have around 190 psi compression on both cylinders, giceor take 5 psi. Confirmed valves to be properly adjusted, 26 psi of fuel pressure, recent spark plug and fuel filter change.

I have checked for vacuum leaks, I have followed the repair manual to confirm my coolant temp and MAP are within ohm spec. I also have my 5v reference on both of those s

I’m leaning towards a faulty/dirty fuel injector but if this was the case I’d think it would blow black smoke all the time?

I’m Kind of stump on this, I don’t want to throw parts at it. I’ll take it to John Deere before I do that!

If anyone would have some ideas I would reallly appreciate it. Mowing season it’s here in southern Ohio!

Thanks in advance
 

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I would bet on the Fuel Injector. When you start it up for the first time after setting for a period of time or over night, does is sound like it is running on both cylinders or just one? If one, I would suggest you shut it off and pull the drivers side spark plug and see if it is wet from gasoline. I had that issue on my 1994 vintage 445 and found the injector was dripping after it was shut off and the way the injector is mounted in the throttle body the fuel will wind up in the drivers side cylinder. It took me several years to find the problem as the tractor ran great after the first cold start of the day. Eventually it got bad enough that every time I shut it off for a few minutes, I would have the missing power from the drivers side cylinder. I replaced the injector and she is purring like a kitten now. Unfortunatly, I could only get the injector from JD. It seems no one else used that Kawasaki engine with Fuel Injection in any other equipment so it appears to be a JD exclusive.
 

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Discussion Starter #3
Thanks for the reply!

It runs on both cylinders cold and hot just not very smoothly. I have been getting some light blue smoke out the exhaust on start up and for a few minutes while warming up. This could have been due to the oil be extremely overfilled because of the fuel dilution.

Maybe I’ll pull the air cleaner after shutdown to observe the fuel injector. When it’s running it I should be able to see it spraying a nice stream of fuel correct?

-David
 

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Yes, I believe so. I have never looked at mine when running. If it is leaking, you should see a stain on the throttle body just below the injector and it will show the injector off set to the drivers side. Good luck on finding the problem. By the time I figured it out, I had a 20# difference in compression between the cylinders. 175 left and 195 right if I remember correctly. Tractor still runs good and doesent burn any oil. I do get a puff of smoke when starting and I have over 1040 hours on the tractor, I did a major PM last spring replacing all the remaining plastic gears and the head gaskets. I was losing Anti-freeze over the season and found no leaks. I did find the head gasket defective and have had no issues since. Hopefully I will get it started today and get the mower deck installed. Been in the heated side of the barn since October.
 

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All depending, you may not be able to notice the injector by watching - but its worth trying. From what you describe, I would tend to guess that your injector(s) is the issue - Not enough of an issue to affect while running much initially (but getting worse now). The big issue is after you turn it off, the remaining pressure in the line has time to slowly bleed into the engine where it makes it to your oil.
 

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Discussion Starter #6
All depending, you may not be able to notice the injector by watching - but its worth trying. From what you describe, I would tend to guess that your injector(s) is the issue - Not enough of an issue to affect while running much initially (but getting worse now). The big issue is after you turn it off, the remaining pressure in the line has time to slowly bleed into the engine where it makes it to your oil.

This makes since, I was trying to imagine how the fuel got into the oil while running. Injector bleed off after shutdown makes the most since.

Is there any other check I could do to verify to debunk the injector causing my poor running condition and fuel dilution? From what I recall, these single injectors are pretty pricey.
 

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The only other thing I could think of is leaving the pressure test rig set up over night and see what happens.
 

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Pull the injectors, turn on fuel pump, and see if leaks occur. **However, I don't know if you can have the injectors off the engine and still connected to the lines? Might need to make a creative connection.

If you watch cleaning videos, you use hose/tubing etc to connect a spray can to the injector. I don't know if the spray can creates enough pressure to see a leak? Or how long you need to monitor for a leak (overnight certainly sounds safe, but you won't hold the spray can that long). If you are leaking, there is a good chance that it is just dirt/buildup that's preventing the injector from sealing off. So cleaning might solve it.

However for piece of mind, I would want to see the leak first and then know that cleaning fixed it before sticking it back on the engine.
 

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Injector can't be removed and pressurized. It is not like an normal injector. You can see the injector tip just by looking down the throttle body. There is only one injector for the 445. Unless you heve very good fabrication skills, I don't see any way you could clean it at home.
 

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Discussion Starter #10
The only other thing I could think of is leaving the pressure test rig set up over night and see what happens.
I’ll do this. I cant think of a way to clean them at home due to the design of how the fuel enters the injector.

As far as how it runs, the bad injector could be spraying inappropriately not allowing the fuel to atomize?
 

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I know, I ran into the same problem trying to figure out a way to clean the injector myself. If it was leaking and did not shut off completely it could be causing a rich mixture causing the poor running. These tractors don't have any oxygen sensors to control the fuel mixture and no way of learning what the proper parameters to run properly and without proper test equipment we just would not know if there was a proper spray pattern or not. I just started and ran my unit today and she is running good. I had a heck of a time installing the mower deck, some dumb person could not get the mower control arms to drop. Seems he was operating the wrong lever. Took my wife to point me in the right direction. Oh well that is why I married her to help me when I have a brain fart.
 
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If your injector is leaking, then it would affect running - both in fuel dispensing and possibly in compression. How much it affects will depend on the condition of the injector. But all symptoms seem indicative of a bad injector.
 

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Discussion Starter #13
I really appreciate everyone's input.

Ill have a look at the fuel injector in the next few days. Work has me getting home late in the evenings but this is what the weekends are for... Time to play!

Thinking ahead, anyone have a part# for that little fuel injector or the best place to buy one? I really don't want to go the ebay/used route.

Thanks!
 

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Discussion Starter #14
Finally got a chance to perform a fuel pressure leak down test. As a few of you suspected, the injector is leaking.

Below is a few pictures of my readings. I initially get 25-26 psi after the pump kicks off. Within 30 minutes it dropped almost 6 psi and I had fuel dripage and gas fumes in the intake.

Looks like I’m in the market for a fuel injector.. Nice to have piece of mind I found the problem and not guessing at a solution.
 

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