Low power and lots of smoke(complete overhaul)D6H

[992G]

Construct'o.
Does this machine still have the original precleaner assembly on it from the factory? Have been reading this post, and here is something to try. Have the boost pressure checked, if it is low, recheck it with the air filters removed. If it comes up to were it should be, and the air filters that you removed are new and clean, remove the precleaner assembly and pressure wash it out. Make sure to wash if from the inlet and outlet side. A build up of dust over the years could be restricting your air flow to the air filters themselves, causing your low power and excessive black smoke. Do not know if this is the fix, but it is worth a shot. I have seen these precleaners get full and cause this problem.

 

[Cmark]

Construct'o.
Does this machine still have the original precleaner assembly on it from the factory? Have been reading this post, and here is something to try. Have the boost pressure checked, if it is low, recheck it with the air filters removed. If it comes up to were it should be, and the air filters that you removed are new and clean, remove the precleaner assembly and pressure wash it out. Make sure to wash if from the inlet and outlet side. A build up of dust over the years could be restricting your air flow to the air filters themselves, causing your low power and excessive black smoke. Do not know if this is the fix, but it is worth a shot. I have seen these precleaners get full and cause this problem.

Good point 992G. I'd forgotten about the precleaner. Used to get blockages a lot with machines working on landfills.

 

[Cmark]

Quick check for the hydraulics. Remove the floor plate and put a pressure gauge on the pump outlet test fitting. Standby (all implements in neutral) pressure should be around 400psi. Relief pressure around 2800.

"Where would i start to check for drag on the hydraulic pumps because you can usually tell if something is running over top the relief and it just doesn't show any signs of doing that.Nothing like when you lift blade to top of stroke and then you can hear the engine pull down at idle ,but that is normal."

But if you've studied the engine noise and it changes when you top out the cylinders, you've probably already answered that question.

 

[pushcat]

Here's a total shot in the dark, but could it be a fuel quality issue? I know in the last few years the quality of fuel we've been getting has really dropped. Don't even get me started on biodiesel, that stuff is crap. Used to be able to easily run a hard ten hour day and an hour or 2 the next morning. Now it's hard to make it a full day. I've noticed it in all our machines, but especially in our D6H also. I've also seen a very small loss of power and more smoke, but it doesn't appear as bad as yours. Like you said, 15 years of operating the machine and you tend to notice subtle changes. Also, I'm sure you're running Cat filters, to keep from voiding your warranty. I've tried running cheaper Napa filters, both air and fuel, and learned there is a difference in performance.

 

[willie59]

Just for the sake of being able to say "yeah, we checked that", have we checked that the rebuild tech got the injection pump timing correct?

 

[Construct'O]

Just for the sake of being able to say "yeah, we checked that", have we checked that the rebuild tech got the injection pump timing correct?

Will start here with this question and try to answer you other guys question on this post.If your saying check timing, ,not sure ,but will.The same Cat mechanic replaced the pump on my R and it runs perfect,so he must have done good there.

But the pump was already on the engine when rebuilt so,they might have not gotten the timing quite right:beatsmeWill check that out !!!!! another positive to check.

As for the precleaner thing this is what is going on there.When you look down into the precleaner after taking the screen top off.On the new machine the honeycomb swirl plates are now plastic(old 7E was metal).Why they went plastic i'll never know(metal will take more heat) Cat need to change this.It is and issue!!!!!!

What happens the plastic get hot,it melts and the honeycomb get melted togather(restricts air flow in).Most of you i know that it is for dust, with the pipe running from the precleaner over to the stack and the stack blows the dust coming into the precleaner out the stack.Helps cut down on dust and dirt getting into the air filters as fast.

If you guys check your honeycomb in the precleaner i will bet yours will be melted,unless they have been replaced.

I would around burning brush piles,so not sure that is how they get melted or is the back pressure heat from the stack through the cross over pipe from the precleaner when working at high temps?

So that has been checked and elimated,it is clean(not melted) okay! If you would sometime a few of you guys check your precleaner and see what the honeyconb looks like and report back?

As far as the tubing from the air filters on too the turbo when the filter are out the opening is clean to the curve.Again that was all assemblied when the engine came back. I also went through the drop box(new bearing and checked the gearing) bewteen the engine and the convertor.

Like i said i wanted to have everything right from the radiator back to the transmission,one time deal,then i was going to start with the finals, trans and hydraulic pump,from there on.Then my machine was hopefulling going to run me on out until retirement when every that is probably when my health get bad which is anyone guess?

Anyway that is the update as of now.Sorry for the long post but trying to get all the info in so you guys can try to come up with any new possabilties???

I see guys on here that ask question ,but never give enough info,but also is hard to do in one short post.

The two things so far is the muffler,timing !!!!!!! but what is you thoughts on the liftpump from where this started??? Is that a possibilty if they never changed that out when they did the injection pump.I can see lost of power from that ,but if that would have anything to do with the smoke issuses?

Well thanks for taking the time to post.Again just trying to get as many leads to check before the mechanic comes.The time search always gets expensive when trying to locate and issue like this.

Probably why the Cat dealer didn't want to deal with it.Dealer sometimes just srug things off,when it comes to warranty work seem like,especially when it is not a new machine.Okay better post getting off track:Banghead:usa

 

[Construct'O]

Pushcat for got yours ........ Cat filters and using fuel out of the same tank and other equipment is doing okay:usa

 

[surfer-joe]

I think your machine has a scroll type injector pump, and with the other information you have supplied, I'd now say that the trouble is in the pump. Just sounds to me like it was not rebuilt correctly, and it likely was set to just within spec and not the high side either. I've run into that before. I always hated working on 3306 engines with the scroll system. Two choices; either have Cat do the pump over, on your dime now I guess, or have an independent injection shop do the work.

There is some substance to the pre-cleaner and muffler ideas, have run into both. It's also possible that the injector pump was installed one tooth off. Ran into that as well. Engine performed well on dyno, but when loaded in the machine with all accessories and parasitic loads, it bogged down everywhere but at high and low idle.

Good Luck!

 

[Construct'O]

After all the posts here the secret might just lay in the muffler theory so far.That is the basic thing that might have been missed when i did everything.It wasn't rusted that bad and looked to be reusable at the time not knowing ly it might be plugged!

Like i said i was loosing water which was antifreeze out through the exhaust pipe because it was showing up on the brushguard where the exhaust was blowing toward.

Antifreeze it sticky,so is the muffler full of the baked antifreeze and carbon,plus the excess oil usage.Would the antifreeze gum up the muffler,sound possible since it is so sticky when you get it on your hands.

This would be something that i not sure? that didn't get replaced, (key)before overhaul and after the overhaul.

The theory of timing after i think about it, was that if timing was off now that it would have to have been off before, and the pump had never been off the machine since new.Not that after the overhaul it couldn't be off now.

"The MUFFLER !!!!!!! to me hopefully is the clue to my fix.":beatsme

Would just like to hear a few more comments on the antifreeze plugging the muffler and then i will give this thread a break.

So will let you guys know how eveything turns out and thanks for all the reply and help:usa

 

[willie59]

One thing I think we can agree on; by the time this machine gets fixed, we'll know everything about a D6H!:yup

 

[surfer-joe]

Easy test. Pull muffler off. Run tractor. If no more problem with low power and smoke, trouble found.

 

[992G]

The antifreeze going through the muffler could possibly be the problem.:beatsme

Remove the muffler and try running it, before buying a new one. It might be a little loud, but you should notice the power come back.

 

[992G]

Sorry Joe, did not mean to say the same as you, guess your faster typing than me.

 

[d6peg]

Constructo,
Your 6H sounds like it is doing the same thing Dad's 5H did after it was over-hauled. We put a new torque converter on it and finally decided after about $5000 dollars spent on trying to find the problem in the engine after the over-haul we went back to the t/c and it was a bad rebuild, that being said we sent it back and got another t/c and problem solved. I know you said the tranny checked out fine but might be worth a look at the t/c. Just pull the plug on it and if it has more than 1-2 gal of oil in the housing you might have a leak and it could be loading the engine down.

Just my $.02. Hope you get her going.

 

[John C.]

These kinds of problems can drive you nuts over time so I feel for you.

I have seen broken baffles in mufflers that change the flow characteristics and really change the output of the engine. We had that problem with Komatsu S6D170 engines in early nineties. I've cut several wheel loader and excavator mufflers apart and found just that. I have not seen that in Cats at all but that doesn't mean that it isn't possible. The idea that the muffler is plugged up is an interesting possibility. Since it has run so long with the black smoke, I'm sure it will have a very thick coating of soot inside.

The most common item that I have seen cause this in Cats is leaking converters slugging the housings. I don't know how the D6H case is scavanged but I'm guessing there is a scavange pump either on the bottom of the converter housing or somewhere on the transmission. Since scavange oil is dumped into the lube circuit for the transmission you might not see high transmission temperatures.

Retarded fuel injection timing will also cause loss of power and lots of smoke. I don't know which method is used to time this pump but I seem to remember a timing plate being installed on the engine or the pump somehow and then the pump stabbed into the gear train on the engine. I know there were different ways of timing these things and it is entirely possible for engine people to use the wrong tool.

When you do find out what is wrong I would not recommend you telling the dealer what you found. Use it as a lever in the future, unless of course they want to pay some of your bills.

 

[Cmark]

As for the precleaner thing this is what is going on there.When you look down into the precleaner after taking the screen top off.On the new machine the honeycomb swirl plates are now plastic(old 7E was metal).Why they went plastic i'll never know(metal will take more heat) Cat need to change this.It is and issue!!!!!!

What happens the plastic get hot,it melts and the honeycomb get melted togather(restricts air flow in).Most of you i know that it is for dust, with the pipe running from the precleaner over to the stack and the stack blows the dust coming into the precleaner out the stack.Helps cut down on dust and dirt getting into the air filters as fast.

If you guys check your honeycomb in the precleaner i will bet yours will be melted,unless they have been replaced.

I would around burning brush piles,so not sure that is how they get melted or is the back pressure heat from the stack through the cross over pipe from the precleaner when working at high temps?

So that has been checked and elimated,it is clean(not melted) okay! If you would sometime a few of you guys check your precleaner and see what the honeyconb looks like and report back?

Hi Constructo

You're quite right, the plastic tubes do melt. The reason for this is there is a "check valve" in the line between the precleaner and the stack. Sometimes it is in a "bulge" on the precleaner, sometimes it is a seperate steel can installed in the line. This valve is just a tin flap on a hinge and it stops exhaust gas entering the precleaner when the exhaust pressure is more than the precleaner pressure. This flap breaks and falls off. That's why exhaust gas gets back into the precleaner and melts it.

I hear what you say about removing the mushroom and looking in the top, but in my experience (and would I guess 992G's as well) the blockage occours in the chamber underneath. You can only see this by removing the precleaner and looking in from the bottom.

Can I suggest simply removing the air filter cover and trying a run? It would be a quick way to check.

 

[Cmark]

By the way, if you want to know why the precleaner changed from metal to platic, you'll have to ask Donaldson. They make 'em.

 

[Construct'O]

Cmark and John C i keep going back to what was going on before and still now after all has been done unless something sliped through the cracks during the overhauls.

Could the convertor been bad before and they missed it in the rebuild,like stated??? I just don't know? I should have kept on them,but was getting wore out from fighting with them, then they come up with run it,not broke in yet.

Everything to drag it on until the warranty run out.Time wish two years not the 2 thousand hours.Had to many workday down because the weather ,floods,wet, and winter seasons.

What about the check of the convertor is what D6peg said about draining the convertor a way to check?

Just going to have to get my mechanic down here and start.If muffler easy fix, if convertor expenssive,unless i can prove they did get it right up at the dealer.I hate REDO's when you pay someone good money to get it right the first time!

We did have to replace the seal on the convertor after we got it running first thing,they pinched it when they put it back togather.I chewed on them about that hard.There shop is almost spot clean up there at the dealer then we have to tear it out under the dozer in the dirt,which we was clean about but you get the point.

So anyway starting with muffler and go from there.I have never had good luck with rebuilds,always something.They are never like when they roll out of the factory ,or has been for me.Every machine i have bought new has run over 12k to this one 16K hours with just normal matinence.

Anyway thanks guys just going to give this thread a rest,but will let you all know what we find unless i run out of money trying to find like D6 peg said.5 grand to find out, that it was a bad rebuilt convertor!!!!!!!

Hoping it is the muffler,just can't be that simple probably.

Well be showing my Cat mechanic all these post,and even the dealer if it is something that they messed up on.Not faulting my mechanic he is a good mechanic and try to look out for his customer,:usa

 

[Construct'O]

I well say this that most machines that i have been around with to much oil in the convertor,when you first try to move them it is like there stuck in the mud.

As far as that the H doesn't seem that way to me,but about now i'm wondering if i know anything??? Thanks again and good night:usa

 

[Iron Horse]

I was asked to diagnose a series 60 in a truck that was blowing huge amounts of black smoke and had no power . The truck had been hit in the front and had just been repaired but they could not find what was wrong . I took it for a drive and came back . The boss said "what do you think?" I said theres a pair of pyjamas in the intercooler . He looked at me with an astonished look . I said trust me . They pulled off the cooler pipes and sure enough , out came a ladies dress . He said "i'll kill that mechanic , why would he do that ?" I said , i'd kill him if he did'nt while the system was open . The trick is to pull it out before putting the pipes back on . Does your engine have an intercooler ? If not have you checked inside the intake pipes ?