[xcopterdoc]

What plugs are installed? On NGK plugs the lower the number the hotter. Remove a plug and get the number. Also, looking at plugs is a good diag tool. See what they look like.
Also not uncommon on these engines for it to drop a coil. Install 2 inline spark testers and compare spark. When it messes up, have a look see at the testers.

Sent from my LGL52VL using Tapatalk

 

[mcgee10]

Did you

I only have one question for you. Did you tell your dealer or JD that your running sea-foam threw your engine?

 

[64882]

What plugs are installed? On NGK plugs the lower the number the hotter. Remove a plug and get the number. Also, looking at plugs is a good diag tool. See what they look like.
Also not uncommon on these engines for it to drop a coil. Install 2 inline spark testers and compare spark. When it messes up, have a look see at the testers.

Sent from my LGL52VL using Tapatalk

The plugs are the correct NGKs straight from the dealership. I adjusted the gap slightly to match what the JD manual calls for. I pulled them today (they only have about 5 hours on them since the fix) and they were caked black like the previous time. Too much gas again I think. I don't have the tool you mentioned and at this point I am just going to take it in to the dealer again. I'm not very good at anything other than minor troubleshooting and maintenance unfortunately.

 

[64882]

I only have one question for you. Did you tell your dealer or JD that your running sea-foam threw your engine?

Yes, I told them I ran SeaFoam after the engine started malfunctioning. They said that was fine and they sell it in their repair shop.

 

[kbeaag]

I've been following this thread for some time , and it appears your JD dealer has some recent employed mechanics with a new set of tools and may have started yesterday.

When you get into EFI fuel related engines, most all problems point to "sensors", as that what really regulates the fuel to these engines. I would think...and I don't know the "ins and outs' on the X738 tractor, but, I would bet it has a "coolant, vacuum, and air temp sensors" that is tied into the fuel system. I've read where your are not "heavy impounded" with mechanic tools, and not adapt in all aspects of mechanical abilities. Ethanol is the worst thing to come down the pike to destroy fuel regulators, fuel pump seals, and when it gets past all those fuel fittings, it washes down all the cylinder walls of the oil they need...causing more damages to these engines.

Here's what you need to do now. Buy you a $15.00 to $20.00 stethoscope and get your hands dirty by "listening" to the injectors with it to see whether they injectors are "clicking". If they are not clicking like in heart beats, they're not working, or one or more of the sensors are sending too much fuel to the cylinder causing the cylinder heads to flood...black carbon buildup on the plugs, etc. and poor engine performance, rough idling, and all the other things that makes any engine run out of normal rhythm.

Applaud your resourcefulness, You can vary the injector volume capability within certain limits, but I expect that those will be too high for the system to accommodate. I don't think it will be able to put in enough fuel trim to compensate for that high flow in closed loop mode. In open loop mode, they will almost certainly be hopelessly rich.

If you have run it an hour or so since the injector installation, pull a spark plug and make sure it isn't sooty black. If it is, then my suspicions are correct. Such a rich condition will not be good for your engine. It will wash the oil off of the cylinder walls, drastically shorten plug life and other maladies including high fuel consumption.

Just wanted to make sure that you are aware of this and I hope this.

 

[64882]

Plugs

Here are 3 pics of the new plug with about 5 hours on it.

 

[jgayman]

Wow... those look as bad as the one in my Ariens rider with the single cylinder 31-series B&S engine. The plugs blacken within the first few hours. Otherwise the engine starts and runs perfectly.

 

[mr moe]

Have seen a few injected Kawasaki engines where the fuel pickup line in the tank, above the pump, was split. The regulator does not get enough fuel to properly regulate fuel pressure and volume.
The computer would then dump all the fuel available to the injectors, which is too much.
Sounds complicated I know.

Pull the return line off at the regulator. There should always be a health fuel flow returning back to the tank.
If there's not, the the regulator is not getting enough.
Not enough fuel to regulator, equals to excessive fuel to plugs.

I missed it, but are both plugs fouling up?

More thoughts:

Have seen a few individual ignition coils on Kawasaki engine quit.
Possible bent push rods on one cylinder.
Plugged air filters. Some of those Kaw. engines draw the incoming air (dirty) to the inside of the filter.
Exterior of filter looks clean because its the clean side.
Inside is plugged and can be missed.

Please keep use informed.
Moe

 

[SulleyBear]

If one plug looks like that and the other is normal, then it's not an air filter issue.

The plug appears to not be firing correctly, which would point me towards the ignition trigger coil first, especially since it's one cylinder. I would want to rule out the spark plug is not defective with a new spark plug, just to be sure. Simple first.

Too much fuel would also cause the same problem, but again, it's back to one cylinder verses two. So, the cylinder with the bad spark plug is either;

A. - Not firing at the correct spark, which would cause me to test the coil for both cylinders and compare them. Chances are the spark is weak on the loaded up cylinder.

B. - Getting too much fuel in that cylinder, which could be a bad injector.

C. - Could be a bad plug wire as well, but the plug wires on these are part of the trigger coil assembly so the assembly must be replaced to replace the plug wire.

The part numbers for the trigger coils are different for the cylinders, so it's important to get the correct one.

If the coils test normal, and the injector is operating correctly, if it were mine, I would want to run a leak down on both cylinders to rule out a broken piston ring, etc. for the cylinder which is showing the terribly fouled plug. Since the problem comes and goes, this is very unlikely but if it isn't a coil issue, plug issue, plug wire issue or injector issue, the only thing left is fuel and it seems like the dealer has been down that block replacing a couple of regulators and a fuel pump.

My guess is the dealer replaced the plug or cleaned it and reinstalled and then declared the problem solved. Well, it's going to run ''more normal" with a new plug until the plug fouls again.

 

[64882]

Sorry for not specifying. I only pulled one plug to see how it looked. I am 100% confident the other looks exactly the same.

 

[64882]

Dropped the x738 off for service today and shared my video showing the engine stuttering to the tech. I get this bad feeling I've got a lemon and I don't want to keep taking it in for repairs (2nd time in 3 months) because I have to rent a trailer and drive 2 hours round trip to get it serviced and pay someone to mow my yard in the interim. Then back again to pick it up. That's a lot of time and money wasted and I'm getting pissed. With all that being said, I'm debating about trading in my x738 for the x758 and make the switch to diesel. I know I'll take a big hit on the trade, but I'd rather take a known hit up front then continually take the x738 in for repairs, and also run the risk that the engine is short-lived due to all its issues. I've already sunk $2,500 into x7 accessories that I want to stay within the x7 line.

Luckily, the dealer has an x758 when I dropped my x738 off yesterday and I checked it out. I was surprised how loud it was, but I have never owned a diesel before. Outside of the money aspect here are my pros/cons of upgrading:

Pros: get rid of problematic x738, diesel has more torque and should last longer, no longer driving across town to purchase ethanol free gas, better gas mileage
Cons: diesel is louder

Thoughts are appreciated. Thanks!

 

[mike01]

Thoughts are appreciated. Thanks!

Do it!! The diesel engine is substantially more powerful. The numbers don't tell you that, but trust me, I've had/used both and there is no contest. It has to do with where and how both engines generate torque. Also, resale value will be higher, fuel economy will be better and the tractor will last forever if taken care of. A gas engine can last forever too, but as you have experienced, there are more things that can go wrong, even with an EFI engine.

Biggest pro...NO SPARK PLUGS!!!

Also, there's just something about a diesel.

 

[SulleyBear]

Dropped the x738 off for service today and shared my video showing the engine stuttering to the tech. I get this bad feeling I've got a lemon and I don't want to keep taking it in for repairs (2nd time in 3 months) because I have to rent a trailer and drive 2 hours round trip to get it serviced and pay someone to mow my yard in the interim. Then back again to pick it up. That's a lot of time and money wasted and I'm getting pissed. With all that being said, I'm debating about trading in my x738 for the x758 and make the switch to diesel. I know I'll take a big hit on the trade, but I'd rather take a known hit up front then continually take the x738 in for repairs, and also run the risk that the engine is short-lived due to all its issues. I've already sunk $2,500 into x7 accessories that I want to stay within the x7 line.

Luckily, the dealer has an x758 when I dropped my x738 off yesterday and I checked it out. I was surprised how loud it was, but I have never owned a diesel before. Outside of the money aspect here are my pros/cons of upgrading:

Pros: get rid of problematic x738, diesel has more torque and should last longer, no longer driving across town to purchase ethanol free gas, better gas mileage
Cons: diesel is louder

Thoughts are appreciated. Thanks!

You will LOVE the diesel.....Just buy some hearing protection where you can listen to music and move forward.

If you liked the X738, you will be giddy happy with the x758.......This will make the x738 just a bad memory.....

The Yanmar has been used in this series of tractor for around 30 years with excellent results. Just DO IT.....

 

[64882]

So the technician is unable to replicate the issue, which I am not surprised by. That reaffirms my decision to trade it in for a x758.

 

[Zebrafive]

Does your tractor come under the John Deere "Promise" where if you don't like it you can return it? Might make the "hit" a non issue.

 

[64882]

Does your tractor come under the John Deere "Promise" where if you don't like it you can return it? Might make the "hit" a non issue.

Unfortunately not, its over a year old now.

 

[Boonie]

What ever became of the issue?

 

[64882]

What ever became of the issue?

Ended up trading it in on an x758 which is a beast. Went ahead and added the 3PH which has been awesome to use.

 

[Sportshot2]

I just stumbled across this thread and decided to add my experience with a X728 with the efi Kawasaki engine and about 1000 hours . I was having issues with it backfiring and missing in cold weather and the dealer hadn’t solved it after a couple hours of troubleshooting.

When I went to change the fuel filter their is a bleeder screw on the base of the intake manifold that I had to use to relieve the fuel pressure. After changing the filter and tightening the screw I realized that the screw slot was not in the same place as when I started. The screw was about 1/8” tighter. The tractor ran much better and i never had an issue again. I believe the screw was not tight and allowed more air into the system then the sensors where measuring.