..another DK 35 making oil

[VictorW]

I'm curious as to what 'fuel knock' is?? Having been around oil burners all my adult life, I've never heard fuel knock.

Please enlighten me??:confused2:

I read it as he was meaning the cylinders were possibly overloaded with fuel because of a bad injector(s) and not firing giving that nice rapping sound. I guess I shouldn't have assumed.

 

[zukota]

something like that. I guess all the oil burners do it.. it's really obvious in this video..

[ame=http://www.youtube.com/watch?v=s2pEM3fAepw]1982 Mercedes 300D diesel - knocking sound - YouTube[/ame]


If it knocks on all cylinders it's probably injector pump timing (which I may have) or if it's on one or a few cylinders it's likely an injector putting in too much, not enough, or even a bad pattern of fuel that changes the timing of that one cylinder only. Edit: this is what I'm hoping..

Pump timing is the last thing that I will have to check if the injectors test good and my lift pump wasn't at fault. Mine knocks really bad on a cold start.. I never liked it.

 

[jonyyuma]

[ame=http://www.youtube.com/watch?v=s2pEM3fAepw]1982 Mercedes 300D diesel - knocking sound - YouTube[/ame]


If it knocks on all cylinders it's probably injector pump timing (which I may have) or if it's on one or a few cylinders it's likely an injector putting in too much, not enough, or even a bad pattern of fuel that changes the timing of that one cylinder only.

that's the last thing that I will have to check if the injectors test good and my lift pump wasn't at fault - injector pump timing. Mine knocks really bad on a cold start.. never liked it.[/QUOTE]
Diesel knock..
Exactly how it sounds. I had a bad injector in My MB . It also stinks very strongly from the exhaust..I was afraid it was going to break a Piston before i could get it home..I replaced it, sound went away..

 

[ecruzin]

Have a few questions. Does the fuel knock go away as the engine warms up? Have you checked that the glow plugs are working OK? If the glow plugs are not working correctly, you can have a lot of fuel "wash down" untill the engine warms up. In real cold weather, I usually wait until I hear the glow plug relay shut off before I start the engine. The relay has and audible click about 5 seconds after the glow plug light goes out. Once you start the tractor, do you run it for a few hours at a time or just a few minutes? Cold starts definately increase fuel contamination in oil. If you are using off-road diesel, you may want to try a fuel additive such as Redline 85 or BG44k first and run it for a few hours at higher RPM and under load to see if it clears out. Since the engine only has 120 hours on it, I doubt that pump timing is an issue since that is usually a function of timing chain-gear wear. If you do end up taking the injectors out, replace the heat shields and gaskets. Hope this helps.

 

[zukota]

Have a few questions. Does the fuel knock go away as the engine warms up?

Yes.. or at least it gets much quieter. I have no real reference for what a dedong should sound like. The neighbors around me have a New holland, kubota, and bobcat (skid) they all sound much smoother. But I also had a 2nd gen cummins - so a noisy diesel isn't exactly a 'bad' thing.

Have you checked that the glow plugs are working OK? If the glow plugs are not working correctly, you can have a lot of fuel "wash down" untill the engine warms up. In real cold weather, I usually wait until I hear the glow plug relay shut off before I start the engine. The relay has and audible click about 5 seconds after the glow plug light goes out.

Glow plug light on the dash never worked. I can hear the relays click on and off. I've verified I have power to the plugs - but haven't checked to see if they are drawing the correct amperage. It's a little cold blooded, but it's never given me any real trouble.

I think I'm putting too much fuel into the crankcase to just be wash down.. I can see it on the dipstick (looking for it) in about 10 hours of running (maybe 3 cold starts), and that most recent 10 hours was in the warm spell we had a few weeks back.

Once you start the tractor, do you run it for a few hours at a time or just a few minutes?

More often than not it's hours.. I don't like to fire it just to take the trash down, but it does get jockeyed from time to time.

Since the engine only has 120 hours on it, I doubt that pump timing is an issue since that is usually a function of timing chain-gear wear.

hope you are correct - I really don't want to go down that road.

If you do end up taking the injectors out, replace the heat shields and gaskets. Hope this helps.

Thanks, that's what I wanted to know - I did order a set. service manual tells to drive in a philips and 'twist' them out. That sounds a little hokey.. hoping they aren't in very thight.

 

[zukota]

Update:


Parts arrived early this week. Last night I swapped out the lift pump and changed the oil. It took longer do do the oil change then swap the pump, so I decided to wait on the injectors until after I rule out the pump.

I'll report back in a few (tractor) hours and let ya'll know.

Thanks again!!

 

[VictorW]

Thanks for the update. I sure hope the lift pump was the easy fix but the way you say it sounds on startup points to probably at least one injector.

 

[zukota]

Update.

I've put about 4 hours on the machine since I changed out the lift pump. So far I'm unable to see any extra oil on the dip stick. I swear it's smoking less, but I don't know if that's even possible?

Regardless, I'll watch it for a few more hours, change the oil again and then run it. Cautiously optimistic, that the simple answer was correct.

Thanks for everyone's help, no more updates unless there is a problem - no news is good news. I will post a follow up oil analysis in about 50 or 60 hours. But that will likely be next year.