4120 Engine problem- Any Ideas?

[GalwayBoy]

Hello group. I seem to be having some problem with my 4120, and am looking for suggestions before I have to trailer it to the dealer.

When working the machine for over an hour the engine will develop a hollow sounding exhaust, like it's floating- similar to a Jake Brake. It seems to lose power as well, with the rpm's I would generally use for given tasks. Hydro effort seems down during these times also, and I can hear it straining when lifting a full bucket.

Tractor can prove slow to start following these episodes, and seems to just be noisier overall.

There are no service bulletins on my machine at present.

Unit was placed in service 11/05 and currently has 380 hours clocked. Fuel filter was changed at 370 hours, oil per schedule with Rotella synthetic. Engine operating temps have been consistent all along.

Has anyone experienced similar issues? I figure I will have to take it to JD, but hate to have to borrow a trailer, and also to lose the use of the tractor.

Jon, in Galway, NY

 

[AKfish]

Wonder if it's injector related...? Or injector pump. Kennedydiesel and others have mentioned issues related to the Stanadyne fuel system on the new PowerTech engines.

Have you called your dealer and detailed your concerns to him, yet?

Under warranty....?

AKfish

 

[GalwayBoy]

Unit is still under warranty, and my dealer knows of the situation.

I bought the machine, then moved some 200 miles away. If it has to go into the shop, it will go to a nearby dealer not to *my* dealer. I expect that will complicate things somewhat, but hopefully won't be too traumatic.

I want to be sure to have it 100% before the warranty runs out in November.

Jon

 

[Mighty Dodge]

Do these tractors have hydraulic valve lifters? If they're mechanical sounds like maybe the valve clearance may be off or maybe a valve is sticking?
Just a thought.

M.D.

 

[jamestaylor72]

Hello group. I seem to be having some problem with my 4120, and am looking for suggestions before I have to trailer it to the dealer.

When working the machine for over an hour the engine will develop a hollow sounding exhaust, like it's floating- similar to a Jake Brake. It seems to lose power as well, with the rpm's I would generally use for given tasks. Hydro effort seems down during these times also, and I can hear it straining when lifting a full bucket.

Tractor can prove slow to start following these episodes, and seems to just be noisier overall.

There are no service bulletins on my machine at present.

Unit was placed in service 11/05 and currently has 380 hours clocked. Fuel filter was changed at 370 hours, oil per schedule with Rotella synthetic. Engine operating temps have been consistent all along.

Has anyone experienced similar issues? I figure I will have to take it to JD, but hate to have to borrow a trailer, and also to lose the use of the tractor.

Jon, in Galway, NY

Hey Jon,,, I'm curious, did you ever find out whats causing the problems with your 4120 ?? I have the same tractor and am sorry to see your having problems with yours. Hopefully its something they can remedy quickly !!

 

[GalwayBoy]

I went to my local JD dealer yesterday and spoke at great length with the service rep. He made no attempt to hide his dislike of the Powertech engines.
Said that they're a great product, just not well suited for tractors.

He'd personally done quite a few of the injector spring recall units(which doesn't apply to mine) He's had JD replace one entire engine under warranty.

Anyway, back to mine.
When I start the tractor, I can place my hand on the exhaust manifold, and the two center cylinders get hot right away , as does the back one. I can leave my hand fully on the front for over a minute. It will heat up if I raise the throttle.
It's also come to my attention that I no longer have the characteristic rev up at start. So we're looking at some type of fuel delivery issue. I'm going to grab a cheap infrared thermometer and record exhaust temps @ the manifold at startup, warmed up, and also during a miss condition to further narrow down what's happening.

The rep was very receptive to my problems, but stated that if anything is to be done under warranty, it absolutely must be done within that time. His JD regional rep apparently does not care how many times I go to complain about my issue. After 24 months, they're done, regardless of whether I told Deere about it or not.

I don't really believe I've any serious malfunction, It's just a matter of diagnosing what it is. With that in mind I'm happy to help him out all I can.
Not likely I could get him over to mow a few acres until it starts acting up....

Jon

 

[BleedGreen]

Jon,

Sorry to hear about your issues with the 4120...

If I may, I would like to throw my two cents in regarding the PowerTech engine, as well as your warranty. The technicians I have talked to (Ag, as well as C&CE - we have 14 stores in three different states) have been very pleased with the PowerTech engines, so I don't know quite where your tech is coming from. PowerTech engines "not well suited for tractors" ??? ??? With the addition of the new 4x20's, we now use PowerTechs from 43 HP up to 450 HP (in the 9520) which would lead myself (and many others) to believe that they work pretty well in tractors.

As far as your warranty goes, the standard is 2 yrs / 2,000 hrs, whichever comes first - but your drivetrain is warranted another year (no additional hours) so I would not worry about the 11/07 date, unless you plan on putting a huge amount of hours on the unit sometime new. Also, in regards to your warranty - If you have a warrantable problem (especially a recurring problem) and your Dealer and John Deere are aware of your problem prior to the end of warranty, it can be taken care of outside of the standard warranty timeline. Again, I don't know where your tech is coming from with his statements. Anyway, just my two cents - hopefully I was of some help.

 

[jamestaylor72]

I went to my local JD dealer yesterday and spoke at great length with the service rep. He made no attempt to hide his dislike of the Powertech engines.
Said that they're a great product, just not well suited for tractors.

He'd personally done quite a few of the injector spring recall units(which doesn't apply to mine) He's had JD replace one entire engine under warranty.

Anyway, back to mine.
When I start the tractor, I can place my hand on the exhaust manifold, and the two center cylinders get hot right away , as does the back one. I can leave my hand fully on the front for over a minute. It will heat up if I raise the throttle.
It's also come to my attention that I no longer have the characteristic rev up at start. So we're looking at some type of fuel delivery issue. I'm going to grab a cheap infrared thermometer and record exhaust temps @ the manifold at startup, warmed up, and also during a miss condition to further narrow down what's happening.

The rep was very receptive to my problems, but stated that if anything is to be done under warranty, it absolutely must be done within that time. His JD regional rep apparently does not care how many times I go to complain about my issue. After 24 months, they're done, regardless of whether I told Deere about it or not.

I don't really believe I've any serious malfunction, It's just a matter of diagnosing what it is. With that in mind I'm happy to help him out all I can.
Not likely I could get him over to mow a few acres until it starts acting up....

Jon

Yeah then, I'd have to agree with you on the fueling problem. Obviously that front cylinder isn't firing or firing to potential. At any rate, good luck with it. I'm sure before long she'll be runnin' back up to full power, and good as new again !!
Jim

 

[AKfish]

Jon, please keep us in the know with whatever JD diagnoses and finally get's fixed.

I, for one, would sure like to know just exactly what the problem is ---

And the other reader's here (especially 4120 owner's) will also have an opportunity to learn.

AKfish

 

[GalwayBoy]

Jon,

Sorry to hear about your issues with the 4120...

If I may, I would like to throw my two cents in regarding the PowerTech engine, as well as your warranty. The technicians I have talked to (Ag, as well as C&CE - we have 14 stores in three different states) have been very pleased with the PowerTech engines, so I don't know quite where your tech is coming from. PowerTech engines "not well suited for tractors" ??? ??? With the addition of the new 4x20's, we now use PowerTechs from 43 HP up to 450 HP (in the 9520) which would lead myself (and many others) to believe that they work pretty well in tractors.

As far as your warranty goes, the standard is 2 yrs / 2,000 hrs, whichever comes first - but your drivetrain is warranted another year (no additional hours) so I would not worry about the 11/07 date, unless you plan on putting a huge amount of hours on the unit sometime new. Also, in regards to your warranty - If you have a warrantable problem (especially a recurring problem) and your Dealer and John Deere are aware of your problem prior to the end of warranty, it can be taken care of outside of the standard warranty timeline. Again, I don't know where your tech is coming from with his statements. Anyway, just my two cents - hopefully I was of some help.

Hello Bleedgreen,
FWIW, the guy doesn't hate the Powertech engine. He thinks they're great in stationary equipment such as gensets and compressors that run at or close to WOT.
His disdain for them in the 4000 series comes from doing recall and warranty work on them from upstate NY all the way to Long Island. New engines with seemingly absurd problems, and some with catastrophic failures.

I'm not knocking the machine. I enjoy working it as much as as I enjoy driving my Volkswagen. And, though V-Dub has had some issues, I'm still a loyal customer. I expect to remain with JD as well.

Jon

 

[GalwayBoy]

Just an update-

Got the 4120 down to the dealer on 7/14. Had the service manager stand by to witness the engine at cold start. "Yep, there's something wrong there" was his reply.

I should have some kind of diagnosis in a few days.

Jon

 

[AKfish]

Thanks, Jon. I'm pretty sure there are more than a few 4000x20 series owner's out there that are watching and waiting to see how this plays out...

AKfish

 

[clarityconnect]

I'll second that as I'm about to receive my new 4120 in about a week and I'm naturally anxious to see how this episode ends or is satisfied. Hope everything ends well and that JD is resposive to this situation/problem.

 

[GalwayBoy]

I picked up the tractor yesterday.
Turned the key, and she revved right up and blew a puff of black smoke. Seemed to run much smoother than before, and with more power. I turned the manure piles with the loader when I returned home, and was satisfied with the power. Just finished up three hours of mowing and had no issues.

The service manager was not in when I called, and in fact, the dealer was closed when I put it on the trailer.The guy with whom I spoke said that they did some work to the rack. The rectangular access cover on the front of the engine has obviously been removed and is newly sealed.

I intend to give a call tomorrow, and ask specifically what was done.

In any case, it's good to have it back! Things were starting to look pretty shabby around here.

Jon

 

[AKfish]

Thanks Jon, for the follow-up info.

Help me out, though... what's the rack? I recall that early diesel engines had a common-line fuel distrubution to the cylinders known as a rail --- but I don't know what a rack is.

Appreciate hearing about your 4120 problem and how you managed to take care of it.

AKfish

 

[GalwayBoy]

AK,
Sorry to disappoint you, but I know about as much about the workings of this fuel system as you do.

I called the dealer yesterday, but the service manager is on vacation this week, and he's the guy who handled my repair. I'll contact him when he's back in the shop and try learn what was done, and some info on the mechanics of the system.

Jon

 

[Green is Keen]

Jon,

Sorry I tuned in late, but glad to hear you got it fixed.

As I read through the thread I was thinking that a lack of fuel to the front cylinder was the reason for loss of power. My guess would have been a failed injector. When the shop "Runs the Rack", they are adjusting the lash in the valve train, which not only opens the exhauste & intake valves, but triggers the injector as well.

No more hours than you have on the engine, someone must have failed to tighten a lock nut.....

 

[GalwayBoy]

Just an update-
Was at the dealer to get hydro oil and some filters in order to do engine and trans oil change, and got to speak briefly my service rep. He also said they worked on the " rack", although he didn't personally work on it. I asked about a subsequent hiccup that occurred while under load, and was told that all the 4x20 tractors do that- even new units on the lot with no hours.

They apparently dyno'd the machine after completion of the work, and are satisfied with its operation.

I'll post a followup if needed.

Thanks for everyones posts!

Jon

 

[RRacing]

I had the same problem but with some added smoke. It was fixed by the rack and injector timing. I got a recall and they had to replace the pump springs and its almost as bad as it was before. They have new specs for the rack and my dealer refuses to adjust it back to were it was as per JD . After owning 5 John deeres I think this will be my last. 3 of the other 4 were jewels. This one has lemon written all over it!!!!

 

[AKfish]

RRacing -- sorry to hear that you're having problems that your dealer won't address.

Adjusting the "lash" on the valves is a relatively easy exercise. Some good wrenches, a screwdriver and a feeler guage. Probably have to replace the valve cover gasket, too. The hardest part is advancing the cylinder's to adjust each set of valves. Need a 1/2" drive ratchet and socket on the crankshaft pulley and maybe a short "cheater".

I haven't kept up with the shop talk --- so, didn't know that "workin' the rack" meant adjusting the valves --- oh, well; I'm gettin' to be an ol' fart anyway...

That said, I don't know if your tractor is still under warranty, but given that you have an established track record of purchasing multiple tractors and implements from JD; I would like to believe that someone, somewhere in the corporate food chain would be very interested in keeping you as a loyal customer.

Don't roll-over on this until you're satisfied that your tractor is working the way it was designed to work!!

AKfish