M59 and EGR Valve

[rScotty]

Hard to believe, but it's been almost ten years and 1000 hours since my we bought the M59. It's been an amazing machine.

But not quite perfect.... it does work well, but in my opinion it has always burnt a little too much fuel and certainly makes way too much black smoke. I've thought about that for years, and I'm now considering disabling the EGR valve for better combustion. Has anyone done that? Any Advice?

The M59 uses Kubota's standard 150 cu. in. 4 cylinder, turbocharged, indirect injection engine (the V2403-M-TE3) vintage 2007. The shop manual implies that EGR valve is an add-on emission solution to an engine that has been around for awhile. The shop manual has an entire new section devoted to the EGR system.

Through the years I've changed several things to make this machine work better for us, but have just sort of ignored the thick black smoke that it makes when starting or revving up, just like I've ignored the rather low fuel mileage. That was easy enough since I didn't know what to do other than think about it awhile. Of course diesels do smoke, but this seemed excessive. Easy to ignore when the rest of the machine works so well.

And I figured that fuel consumption and black smoke might simply be the 7000 foot altitude here. Up here there's less available oxygen in the air - and at first I thought that I'm not going to be able to do much about that....and then one day while enjoying some loader work while listening to the EGR hammer & rattle away....and dodging the smoke plume..... it occured to me that maybe I could do something. After all, the engine has a perfectly good turbo - maybe that turbo is being crippled by the EGR valve. So I got out the shop manual and began to study up. It looks easy enough to do. The EGR valve is driven open by boost pressure from the turbo. Just plug it up?

So that's what I'm thinking.....what do you guys think?
rScotty

 

[kuboman]

I took the egr off my L5740 which uses the same engine. You can disable it or remove the whole thing which is what I did. You will need to get made or fabricate small plates to seal off the port on the exhaust and intake manifolds. I'm betting your intake manifold is cruded up with carbon which will not help at your high altitude.

 

[caballero59]

I've done some research on this also since buying my 2013 M59. I'm surprised yours has the EGR being a 2007 production motor. I thought thought the EGR was an interim Tier IV bandaid. But any way, I dropped mine by the dealer this week to observe the motor as it started. I live at 8000 in Colorado and it always stumbled, stuttered, and smoked for about 5-7 seconds. At 5000' and then later at 2000' in Kansas, this startup stumbling was completely gone...just a puff of black smoke at startup and then running smooth. My L39 and ZD326 mower do this also. But in any case, the dealer immediately asked me what elevation I lived at (a factor?) and told me that he had recently went to a class about the EGR motors and he thought the timing was retarded. Other threads I have found also support this. If the EGR is closed off, I think the timing can be advanced, giving less EGT's and better economy at speed. Another thing that sucks about the EGR is Rotella 5w-40 is not rated for it...too much soot being recycled I guess. I would like to learn more about this also. Not sure but EGTs and cylinder head temperatures may vary in an inverse relationship...which if true, is not completely intuitive for me at this juncture.

 

[caballero59]

I would like to learn how to advance the timing myself but I've done it on my 5.9 12v Cummins and to do it properly using the "spill" method rather than resorting to the timing pin ( very inaccurate) is a bit of a bearcat.

 

[caballero59]

I am leery of only disabling the EGR without changing the timing since the EGR reduces cylinder head temperatures.

 

[rScotty]

I am leery of only disabling without changing the timing since the EGR reduces cylinder head temperatures.

Yes, I've heard that too. It does make sense that the EGR reduces cylinder head temperatures, since it is oxygen that makes a lean mixture burn hot, and what the EGR does is replace some of the incoming charge with some of the already-burned exhaust gases. That reduces some of the oxygen that it be present in a normal intake charge. So the engine burns cooler.

But here at 7000 feet altitude the incoming air has already lost 22% of the oxygen that sea-level air has. (Altitude.org | Altitude air pressure calculator) So our engines already burn cooler without us changing anything. Mechanics deal with this all the time; it's basic high-atitude tuning.
What I don't know, is just how much engine heat does 22% less oxygen represent? Is it significant?

I'm still thinking it through....still leery too. Still looking at the options, and that's why I want to learn as much as I can here on the forum.

I hear what you are saying abouit engine heat, and might feel more favorable to keeping the EGR if I was pulling a big plow or grader at high RPM/heavy loading. But my use is just general loader and backhoe work. Pretty easy, and done at part throttle. Is the EGR helping the tractor here or hurting it?
rScotty

BTW, all the M59s use an interim tier IV engine. As I understand it, adding the EGR is what makes that engine meet "interim tier 1V" emissions.

 

[caballero59]

Pardon me for my #3 post. I had some very unclear writing that I later edited for clarification but somehow, my edits did not get saved.

 

[FatTire]

I'm hoping you do remove the EGR so the rest of us can see what happens, but wouldn't an easier/safer experiment be to advance the injection timing? It is widely believed to be the big issue with Interim Tier 4 at high elevation but I don't know of a single person who has solved the cold stumble/smoke problem at 7000 ft or above. My L5740 has it worse than the MX5100 did, yet they are similar engines.

 

[FatTire]

I've done some research on this also since buying my 2013 M59. I'm surprised yours has the EGR being a 2007 production motor. I thought thought the EGR was an interim Tier IV bandaid. But any way, I dropped mine by the dealer this week to observe the motor as it started. I live at 8000 in Colorado and it always stumbled, stuttered, and smoked for about 5-7 seconds. At 5000' and then later at 2000' in Kansas, this startup stumbling was completely gone...just a puff of black smoke at startup and then running smooth. My L39 and ZD326 mower do this also. But in any case, the dealer immediately asked me what elevation I lived at (a factor?) and told me that he had recently went to a class about the EGR motors and he thought the timing was retarded. Other threads I have found also support this. If the EGR is closed off, I think the timing can be advanced, giving less EGT's and better economy at speed. Another thing that sucks about the EGR is Rotella 5w-40 is not rated for it...too much soot being recycled I guess. I would like to learn more about this also. Not sure but EGTs and cylinder head temperatures may vary in an inverse relationship...which if true, is not completely intuitive for me at this juncture.

On the 5W-40, are you talking about CK-4? There are some 5-w40 still available at CJ4.

 

[rScotty]

Pardon me for my #3 post. I had some very unclear writing that I later edited for clarification but somehow, my edits did not get saved.

No problem caballero59, I thought #3 was clear enough. I'd be curious about how the timing is advanced - in fact, I'd sure like to see some notes from that class he went to. But not so sure I agree that advancing timing is what I want to do. On any type engine, advancing the timing increases burn time and therefore the effective compression ratio...more HP......but it then defeats some of the advantage because the burn begins at such an unfavorable crank angle. And it is tricky to get right; timing that is just a little too far advanced can really hammer on the bottom end wear. All in all, I'd rather come up with a solution where I give up some HP in exchange for a better burn ratio.
I'm in this for a nicer, more economical run - and for longevity; the tractor has HP to spare.

I hope KUBOMAN posts some of the reasons why he removed the EGR completely. I'd just thought that simply defeating the actuator pressure would be enough. I thought about maybe even putting in a manual valve in the boost pressure line to the EGR so we could experiment a bit. But I'm thinking that KUBOMAN may have already thought this through...
rScotty
still wondering if I can get hold of notes from that class....