2013 MX4700 Won't Hold PTO Idle

[jsilver]

I have a 2013 MX4700 that I bought new; it currently has 72 hours on it. It has run smooth, with no problems starting from below zero temps on up. This spring I started reclaiming some acreage from sagebrush. This is the first time I have run a PTO driven implement at 2700 rpm. After 30 to 50 minutes, the rpm drops to about 2100ish rpm and loses power. I have run fuel additives (Seafoam and Hot Shot's) to see if that would clear a problematic injector, and that didn't work. I checked the manifold temperatures and noticed the front cylinder is running consistently 25 to 30 degrees cooler than the other three. This tells me I need to replace that injector. My question is, should I replace all of the injectors if I replace one? And with this model, it appears that I am going to need to pull the air intake manifold simply to access the injectors. And last question, is there a special injector removal tool I will need to do this job? Any advice from anyone that knows will be appreciated. Thanks!

 

[aarolar]

I can't see how you would be having injector issues on a tractor that new.

Sent from my SCH-I545 using Tapatalk

 

[lugbolt]

me neither. I have not seen a 4700 with ANY injector problem. The front cylinder may read cooler because the front of the engine is closer to the fan, therefore your IR temp gun is picking up on the surface temp difference.

I had to put an injector pump in a 5100 once, owner had been running on biodiesel, home-made, appartently poor quality. Same symptoms, run about 45 minutes under load, start to smoke/miss, lose power. Pump fixed it. And yes we had it sent off for inspection and rebuild, nothing was found wrong, which I found odd. Replaced with new Kubota pump and it has run perfect ever since. IIRC the only difference between the 4700 and 5100 are the turbocharger and small difference in the injector pump.

 

[Bulldog]

I would think a bad injector would be bad all the time, not run good for 30 minutes then act up. Or at the very least it would be worse when cold and show improvements when warm, not the other way around.

Have you replaced the fuel filter?

Could have water/trash in the fuel.

 

[jsilver]

Thanks for your comments. I checked and cleaned the outer air filter (which wasn't in bad shape), and the inner looked great. I checked the fuel filter, but didn't replace it. I have been running red diesel from our local coop which has a rep for quality fuel. The only other symptom I left out when it begins to lose power was that it also starts blowing white smoke that smells of unburned diesel. I also ran the engine at 2000 rpm until until hot, but before losing power and the front cylinder was running within a degree or two of the other three. I'll post after replacing the front injector and let you know if that fixed it. (I'm hoping it isn't the pump!)

 

[100 td]

So has this done this once, or more?
Take your fuel cap off and replace it with a piece of clean rag with a rubberband holding it on.

 

[kuboman]

Replace the fuel filter. Unless you ran poor fuel there is no reason for an injector to be bad. I think I would do more investigation before replacing parts.

 

[North Idaho Wolfman]

Sounds like to me the valves need adjusting.
I would do that before changing a injector, and then I would swap 2 injectors to see if the problem follows the injector or stays with the front piston.

 

[jsilver]

I picked up the injector this week and replaced it. I checked cylinder temps when running, but before load and they all looked good. I started brush hogging the sagebrush, and with in 30-40 minutes, the same problem presented again; loss of power, white smoke, and won't hold PTO RPM. I checked cylinder temps while the problem manifested this time, and at least those were consistent, but the new injector didn't solve the problem. So, I'm done trying to diagnose it. Off to the dealer it goes this morning. Thanks for all of your comments and input. When I get it back I'll followup with financial damages and what the problem ended up being.

 

[jsilver]

Well, after five dealer hours of troubleshooting, re-timing the injector pump (dealer said timing was knocked out of whack when I replaced the injector), and running it on the dino for an hour at 2700 rpms, no problem was identified that could cause it to lose power and blow smoke after being under load with PTO for 30 to 60 minutes. Damages for telling me that they couldn't find the problem that started this whole mess? a mere $800.00. Service writer suggested I video record the problem if I get the tractor back and it ends up doing the same thing.

 

[1970cs]

Replacing injector knocked the injection pump out of time?

That's a new one!

The pump has shims underneath it to adjusting timing so I am having a hard time believing that it could happen. If you ever suspect a bad injector, crack the line at injector to see if you have a drop in RPM then it's "firing" and if it does not then something is going on with that cylinder i.e. bad injector, valve lash or dead cylinder.

Now I have seen this happen one time with a cassette style pump. After running the tractor for a while the tractor would lose rpm and blow smoke and would mis-fire (not on your list) but after three trips to our Injection service dealer saying nothing was wrong. We told them to run a heat gun on it and then it finally reared it's ugly head. The body had a crack in it and would open up and lose fuel pressure. 21 hrs of second guessing and trying everything in the book.

Pat

 

[D2Cat]

You better find a different dealer. What Pat said is correct. They're feeding you a line of BS if what you reported is what they said!

I believe when someone will lie one time, you better not believe much of any thing they say, because lying is a habit.