JD6620 running in 5 cylinders

[radu]

2005 JD6620 10k hours started running rough and white smoke was coming out the exhaust.
The mechanic sugested it might be an injector gone so i bought six new injectors (never had any replaced before) which were fit today but the problem was not solved.
Then, while trying to identify the problem, the mechanic loosened the pipes that supply fuel to the injectors in turns and found one that when unscrewed made no difference to the engine sound. It got late so he will return tomorrow and try an old injector in the dead cylinder just in case the new one is a dud. If this isn't the case, what else could it be?

BTW, it's a Stanadyne D10 rotary fuel pump


Radu

 

[Philip Watkins]

Did the white smoke stop when the duff cylinder injector pipe was loose? White smoke is unburnt fuel so I would say injector is good. Maybe broken exhaust valve causing no combustion in that cylinder.

 

[Mursal]

More likely be cylinder rather than injector pump I'm afraid.
But easily checked by piping an old injector up and see if you have diesel spray out the pipe going to the dud cylinder?

Tight tappets (unlikely)
Then a cylinder leakage test using compressed air into the injector port in the head sealed off, listen for leaks out the exhaust/inlet/coolant/sump?
Work from there ..............
We wouldn't go striping down without knowing where the leak is, or you'll be standing looking at each other in a poor of bits.

Edit:
Just be careful with the spray from the naked injector, the diesel can be fatal.

 

[agcon1]

Head gasket, well know for it I'm afraid

 

[SteveO]

I also think it is that damn head gasket. I have done the same one time, bought 4 injectors and then realised that the head gasket is the problem.

Start the tractor and try to press that thick rubber hose on the left side under the bonnet. If it is not soft then it is head gasket. And then ask that mechanic to buy those injectors from you since you did not need them !!

 

[Phil P]

Check for bent/worn push rods, they had a bad batch on some early 20 series. If the inlet isn’t opening properly it will white smoke as there’s not enough air for a clean burn.
Could also be -
Head gasket
Cracked/ bent valve
Top of piston broke away

I’d be doing a compression test then pull it to bits.

The joys of running a deere

 

[ARW]

Head gasket

 

[radu]

I followed @Mursal 's advice and piped up an injector in the air. When connected instead of injector no 6 there was a lower amount of diesel sprayed out at idle and when revving there were times when no diesel was coming out at all. Then we connected the injector on a different outlet and (after all the air in the pipe cleared out) there was much more diesel spat out at idle and the flow was consistent at higher rpm. I made a couple of videos that you can see below:

Me and the mechanic agreed it must be the injection pump which we took off and sent to a repair shop and i'm still waiting for their diagnose.
Can it not be the pump?

 

[Mursal]

Sounds good .................
Keep us posted

 

[Right-arm fast]

Looks like a delivery valve spring broken or sticking in FIP. Good detective work so far, the good port injector is working well

 

[Lincsman]

Could have saved a lot of time cracking each injector in turn, in the first place.

 

[radu]

so, we got a new injection pump and everything went well for ~100 hrs. until it didn't and the tractor started blowing white smoke again. The driver stopped it and after that it refused to start. here's what happened next:
- we thought, since it won't start it must be the injection pump as if it were just an injector it should have started -> we put the old pump back
- while bleeding the fuel lines we discovered that pressure was escaping from the cylinder through an injector. it seems that the new injectors that i got are crap (ordered them online, didn't get exactly what i thought i would but they said made in USA so i thought they couldnt be that bad) and the small nozzle in the tip of the injector had come off (pic below). Then, at every compression stage of that cylinder all the pressure was pushed in the injection pump.
- after we replaced the faulty injector, and some more bleeding, the tractor started with the old bad injection pump. Started a few times, all seemed fine (apart from it running in 5 cylinders because of the old pump)
- we then decided to swap the new pump in as we thought the injector was to blame and the pump should be ok. -> did not start or even give sign any of starting. it would rev faster on brake cleaning spray (no starting spray on hand)
- then we thought maybe the new pump was damaged by that pressure coming from the cylinder so back with the old pump. Couldnt get it to start at all anymore.
- we replaced all the new junk injectors with the old original ones, no luck!

The question is: could the back pressure from the cylinder damage the fuel injection pump? It's a stanadyne DE10. Fuses were checked, computer was connected, no faults there. the nozzle that came off the injector is now embedded in the piston, couldn't see any damage to the cylinder looking through a borescope
As i am typing this i realized we didn't check for blockages in the injector lines but did check the output ports of the inj pump and they seemed fine.



Radu

 

[Mursal]

Pipe a few injectors up to the injector pump and see if its putting out diesel?
Try a few outlets at the same time?

If you have a spray pattern = engine problems (unless timing issues from swapping the pumps?)
If no spray pattern after bleeding = pump or stop mechanism on pump.

I'm afraid the piece embedded in the piston might have done a bit of damage to the combustion chamber, there ain't much room in there. But it should at least run on the other 5.

Be extremely careful of atomized diesel from the injectors or leaking injector pipes

 

[Timbo]

D

I followed @Mursal 's advice and piped up an injector in the air. When connected instead of injector no 6 there was a lower amount of diesel sprayed out at idle and when revving there were times when no diesel was coming out at all. Then we connected the injector on a different outlet and (after all the air in the pipe cleared out) there was much more diesel spat out at idle and the flow was consistent at higher rpm. I made a couple of videos that you can see below:

Me and the mechanic agreed it must be the injection pump which we took off and sent to a repair shop and i'm still waiting for their diagnose.
Can it not be the pump?

DV problem by the looks then.

 

[radu]

First of all i want to thank you all for your time and for the opinions you share here!
Now for an update:
We replaced all the injectors with new ones from the dealer, put the new pump on, put the battery off the combine (the tractor battery wasn't turning the engine fast enough) and after some bleeding, it started!! And now we have an other problem: it makes some sort of rattle sound. It seems to be coming from the front of the engine where i had that injector that parted with it's nozzle which is now embedded in the piston. Could this sound be from the nozzle that keeps banging on the head? The fitter that helped me said there is a risk that the piston might crack because of the nozzle and that i should overhaul the engine, just to be sure. The tractor is ~10k hrs so an overhaul wouldn't be unacceptable but from my experience with the mechanics, and the general rule of if it ain't broke, don't fix it, i don't want to take unnecessary actions that may lead to other problems in the future.

This is the sound it now makes:

The nozzle that is now embedded in the piston:


There is also a mark on the edge of the piston and what looks like a mark on the liner is just a reflection.

What would you do if you were in my shoes?

 

[Mursal]

No room for anything like a nozzle in the combustion chamber, so head off to investigate.
Then decide on action to be taken .............

 

[Flat 10]

I think you should have a look, it sounds not very nice. If you haven’t done it, the head gasket might benefit from being changed anyway......
Your English is excellent by the way.

 

[Phil P]

It’s definitely not a diesel knock as you can hear it on the over run. I’d say it sounds mechanical, possible a cracked ring or a damaged valve. Almost sounds like a small end gone but that’s really rare.
Is it breathing hard?

 

[Pheasant Surprise]

It’s definitely not a diesel knock as you can hear it on the over run. I’d say it sounds mechanical, possible a cracked ring or a damaged valve. Almost sounds like a small end gone but that’s really rare.
Is it breathing hard?

Sounds quite ‘tappety’. Is there a possibility it hydraulic’d on that cylinder with the loss of the injector tip?

 

[Kevtherev]

Sounds like a valve did the injector tip damage a valve?
I’d be getting head off before further damage.