Low on Power - Tech is Stumped

[weldguy]

My son's M6040DTC recently has been low on power after warm up. It's been to three dealers to fix the problem. It won't produce anything over 43 PTO horsepower on the dyno. The supply (lift) pump was down on pressure and was replaced. Then all the injectors were replaced because of poor spray pattern. Kubota then authorized a new injector pump... still 43 horsepower. Compression is great. The Master Tech is frustrated and stumped. It's only 9 months old!
I'm suggesting a Factory Tech meet at the dealer.
Any suggestions?
No black smoke makes me wonder if something with the turbo could be allowing too much boost.

 

[Daren Todd]

Have they checked the intercooler and boost lines from the turbo? Had one of the rubber sleeves on an intercooler line develop a small crack on a power stroke and it caused the truck to lose most of it's butt.

Could have jumped timing too

 

[weldguy]

Wouldn't a crack cause low boost and therefore smoke?

 

[85Hokie]

My son's M6040DTC recently has been low on power after warm up. It's been to three dealers to fix the problem. It won't produce anything over 43 PTO horsepower on the dyno. The supply (lift) pump was down on pressure and was replaced. Then all the injectors were replaced because of poor spray pattern. Kubota then authorized a new injector pump... still 43 horsepower. Compression is great. The Master Tech is frustrated and stumped. It's only 9 months old!
I'm suggesting a Factory Tech meet at the dealer.
Any suggestions?
No black smoke makes me wonder if something with the turbo could be allowing too much boost.

so it MAKES power BEFORE it warms up ?

When you have a turbo - that is a game changer, lots of different problems arise when you force air into a cylinder as apposed to just pulling it in.....
what should the rated HP be in a perfect world of that tractor?

 

[mike paulson]

There might not be enough Turbo boost. Waste gate stuck or Turbo impellers failing. The engine should be put under load and turbo function observed, there are tests that can be done to test turbo function with a scanner but these are all things any competent dealer tech would have done. Fuel pressure and Volume should also be measured. Any fuel delivery system should put out close to a quart at the lift pump in one minute?
All that being said it could be an ECM. Problem restricting injector pulse width or incorrect turbo pump timing if that's applicable. I would insist the dealer get a tech/rep who can find your problem especially if it's under warranty.

 

[weldguy]

Great! Kubota tells my son, "We know it's not to spec on power, but try it and see what you think." That's BS as far as I'm concerned. It's been over a month since the first dealer tried to fix it. Sounds like its time to tell Kubota they are going to be billed for lost revenue because it's taken so long and it's still not fixed.

 

[Tooljunkie]

No disrespect intended, but you are not helping things by taking it to a different dealer because the previous one failed. Forcing a new tech to follow the previous techs steps or repeat them. Seems like they are giving up, or they arent given the time to find the problem. Busy shops dont care for long drawn out diagnostic procedures. Especially warranty ones. They earn less on warranty work.

Had a similar situation with an oldsmobile- owner took it to four shops, mine being the last. After verifying the previous work i spent a great deal of time tracing an electrical problem. Other shops replaced battery, alternator and starter. Was power antenna drawing battery down.

 

[weldguy]

The moves were made because previous dealers each claimed it was fixed, but it wasn't. The original tech said, "I replaced the air filter. It's fixed." The dealer who currently has it is an experienced AG repair facility and those who couldn't find the problem recommended him be ause of the in-house dyno.
What would you do if your new $53,000 piece of equipment had a problem and the "lawnmower tech" blamed it on an air filter??? BTW, it has the problem WITHOUT an air filter.
This is quickly going to turn into a legal battle with the winter season in Ohio approaching. A friend with a Toyota with an issue went to arbitration and she got ALL of her money back, including interest, from the first day the dealer had it to repair.
I feel bad because I talked him into the Kubota when he was going to huy a JD unit.

 

[AZ.]

The moves were made because previous dealers each claimed it was fixed, but it wasn't. The original tech said, "I replaced the air filter. It's fixed." The dealer who currently has it is an experienced AG repair facility and those who couldn't find the problem recommended him be ause of the in-house dyno.
What would you do if your new $53,000 piece of equipment had a problem and the "lawnmower tech" blamed it on an air filter??? BTW, it has the problem WITHOUT an air filter.
This is quickly going to turn into a legal battle with the winter season in Ohio approaching. A friend with a Toyota with an issue went to arbitration and she got ALL of her money back, including interest, from the first day the dealer had it to repair.
I feel bad because I talked him into the Kubota when he was going to huy a JD unit.

That's very easy to answer...Go right to Kubota corporate...Do you have lemon laws in your state?...

 

[Daren Todd]

Did they happen to check it on the dino using a different fuel source (jug, can) with a fresh supply of diesel?

It's been known to happen where gas accidentally gets introduced into the fuel system, and can cause loss of power when the engine gets warm. Around here we've had cases where the delivery guy screwed up and mixed some into a diesel tank at a local store. Or grabbed the wrong hose off his truck and filled a bulk tank. And one time a few years back the local train depot accidentally filled a bulk tank for heating oil with gas. They ended up having to evacuate 30 to 40 homes before it was caught

 

[Wild and Free]

Explain the low power issues, what is he trying to do or what is he doing when it acts up. Is it low on power all the time versus what it used to have since it is nearly new, does the power slowly fall off under heavy load and then recover after is idles or has been shut off for a bit and then fall off again ect. you get what I am after?

From the lack of details of the issue other than "Low power" and only getting 43 hp from a 55 hp pto rated tractor on a PTO dyno that who knows the accuracy of and if or when it was last calibrated and certified can have up to a 10% + accuracy descrepency to start with. I have used PTO dynos a lot in the past having worked at an AG dealership which was also a Kubota dealer many years ago.

I agree that a stuck waste gate would be a good starting point" I had this issue kick my butt while trouble shooting it for several weeks on a newer Komatsu excavator years back". Also check all turbo intake connections and hoses, even a slight loss of boost pressure can cause low power with no smoke.

 

[kuboman]

The 6040 is a strait mechanical injection engine. Over boost will not cause low power. Underboost will give you smoke. The fact that it is low on power after warm up leads me to the EGR. My guess is it is sticking open after warm up. It has 2 factors that cause it to operate. One is water temp the other is turbo boost pressure. I would disconnect it so it will not function and try it again. An overload of exhaust into the engine will de rate the engine.

 

[weldguy]

UPDATE: A memo to a well placed Kubota manager demanding proper repair, replacement, or refund resulted in the dispatch of a top Kubota tech to the dealer. Two days later, the engine was producing 54 HP and needed to be "backed down" to 50 rated! Shimming the injector pump and an "undisclosed" adjustment corrected the problem.

 

[Bulldog]

UPDATE: A memo to a well placed Kubota manager demanding proper repair, replacement, or refund resulted in the dispatch of a top Kubota tech to the dealer. Two days later, the engine was producing 54 HP and needed to be "backed down" to 50 rated! Shimming the injector pump and an "undisclosed" adjustment corrected the problem.

According to Tractordata and the Kubota site both say the engine HP is 63.5 and the pto hp is 56. If they backed your tractor down to 50 your still way under rated. While the problem is fresh on their mind I would make them bring it up to the correct rated hp level.

 

[olthumpa]

What bulldog said.

http://www.tractordata.com/farm-tractors/001/8/4/1846-kubota-m6040.html

Kubota M6040 Power:

Engine (net):63.5 hp [47.4 kW]
PTO (claimed):56 hp [41.8 kW] (late)
55 hp [41.0 kW] (early)

 

[weldguy]

MY BAD...I noticed it's a 5740 when I stopped by his shop.

 

[Bulldog]

That makes a difference but if you're still talking about engine HP it should have 59, not 50.

 

[Tx Jim]

Horse power measured at dealer would probably have to be pto hp measured by way of a dyno which for a L5740 would be 50 pto HP.

 

[skeets]

I want to know how they measured the HP?

 

[Bulldog]

Horse power measured at dealer would probably have to be pto hp measured by way of a dyno which for a L5740 would be 50 pto HP.

I agree with you TX Jim but the man said engine hp was 54 and they backed it down to 50.