How to start diagnosing crank-no-start on a kubota common rail diesel

[TheOldHokie]

Takeuchi owns the right to the Kubota engines they use, so they have their own ECU and diagnostics. A Kubota dealer or Kubota industrial engine service center can not connect to them.

Takeuchi owns its engines, which are different from any others Kubota manufactures. The warranty and software are all Takeuchi's.

Their diagnostic port is also different from what Kubota Tractor and Kubota Industrial use.

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I understood the diagnostic ports and electrical interface are different.

I thought the software was still Kubota Diagmaster with a Takeuchi specific database and Takeuchi specific access credentials. Much the same as Diagmaster with the Kubota industrial database or Diagmaster with the Kubota agricultural database.

Of course that perception is based on the pirated software and screen shots that are all over the web.

Who owns and warrants the Takeuchi engines is a different issue.

Dan

 

[c5vettster]

Well, it will be interesting. The injectors should arrive today or tomorrow. I will plug them in and hope their profile matches the original ones. This also means that even if I were to rebuild the old injectors, they won't likely to work since rebuilding will change their profile. I used to rebuild mechanical injectors and simply make sure that they "pop" using a simple pressure pump-based injector tester. I can still rebuild and test the electronic injectors but calibrating them for the ECU would be a different matter.

 

[TheOldHokie]

Well, it will be interesting. The injectors should arrive today or tomorrow. I will plug them in and hope their profile matches the original ones. This also means that even if I were to rebuild the old injectors, they won't likely to work since rebuilding will change their profile. I used to rebuild mechanical injectors and simply make sure that they "pop" using a simple pressure pump-based injector tester. I can still rebuild and test the electronic injectors but calibrating them for the ECU would be a different matter.

Common rail injectors "pop" as many as 5 or 6 times per ignition event. I think its safe to say the new injectors will not match the old ones. How much the mismatch degrades engine performance is a big question.

Dan

 

[c5vettster]

Common rail injectors "pop" as many as 5 or 6 times per ignition event. I think its safe to say the new injectors will not match the old ones. How much the mismatch degrades engine performance is a big question.

Dan

One would think that the ECU has adaptive abilities to accomodate for some range in injectors? One supposes that any injector spray pattern changes with time, fuel quality, ambient temperature, etc. These are industrial engines and are designed to perform in the toughest conditions.

 

[TheOldHokie]

One would think that the ECU has adaptive abilities to accomodate for some range in injectors? One supposes that any injector spray pattern changes with time, fuel quality, ambient temperature, etc. These are industrial engines and are designed to perform in the toughest conditions.

Sure. The ECU gets its baseline adaptive data via coding. Thats what the code on the individual injectors tells the ECU. The ECU is not going to "learn" that on its own.

Dan

 

[c5vettster]

One would think that the ECU has adaptive abilities to accomodate for some range in injectors? One supposes that any injector spray pattern changes with time, fuel quality, ambient temperature, etc. These are industrial engines and are designed to perform in the toughest conditions.

Well, I may have to buy a bullet and bite that diagnostic software so to speak. It is amazing how few shops know/have the ability to work on these smaller diesels.

 

[TheOldHokie]

Well, I may have to buy a bullet and bite that diagnostic software so to speak. It is amazing how few shops know/have the ability to work on these smaller diesels.

There is more to it than writing a check. If it were that easy lots of people would bite the bullet.

My understanding iz you also have to demonstrate a "need" and attend annual training and certification classes. Licenses are then renewed annually (another check).

Dan

 

[c5vettster]

Well, I may have to buy a bullet and bite that diagnostic software so to speak. It is amazing how few shops know/have the ability to work on these smaller diesels.

You are right. I was thinking about going the "cracked" version route.

 

[TheOldHokie]

You are right. I was thinking about going the "cracked" version route.

Do share that experience! I am sure many here would be interested in what you learn

Dan

 

[c5vettster]

Do share that experience! I am sure many here would be interested in what you learn

Dan

I will! Will update the thread as soon as the injectors are replaced.

 

[c5vettster]

Injectors have arrived and I will put them in after work tonight.

 

[c5vettster]

Well, here are the culprits. I don't see any markings on these injectors and they are the original ones. However, you can clearly see why the engine struggled to start. All three were pretty fouled up but the machine does have 23xx hours on it.

The new injectors from amazon did the trick. Machine started right up and goes up and down in RPM just like it supposed. Stable idle and full throttle. Replacing them was about 3 hour job but this is the first time I did it, so if I have to do it next time, it will likely be more like an hour.

 

[#40Fan]

You'd need to get the paint off to see the markings.

 

[North Idaho Wolfman]

Well based on the paint on the Injectors the engine was a cheap rebuilt or Junk yard recycle replacement.
Cheap or junk yard units get spray painted and cover all the original markings.

 

[GreensvilleJay]

curious about the 'calibration'....With today's 'computer controlled engineering and manufacturing' I'd expect the injectors to be nearly identical so what where are they different ?
Do gas cars and diesel trucks also have to be updated or reprogrammed when new FI installed ?

 

[c5vettster]

curious about the 'calibration'....With today's 'computer controlled engineering and manufacturing' I'd expect the injectors to be nearly identical so what where are they different ?
Do gas cars and diesel trucks also have to be updated or reprogrammed when new FI installed ?

I think it is a common procedure to recalibrate the FI on big tractor-trailers when major components are replaced.

 

[TheOldHokie]

curious about the 'calibration'....With today's 'computer controlled engineering and manufacturing' I'd expect the injectors to be nearly identical so what where are they different ?
Do gas cars and diesel trucks also have to be updated or reprogrammed when new FI installed ?

Injector Adjustment

When the injectors are manufactured, a multitude of measurement data is recorded at specific points in the factory. In this way, the tolerance ranges for injector-quantity adjustment are determined and specified in a six-digit number combination.
Information on the lift performance of the injector is also added for injector voltage adjustment. Injector adjustment is required because of the individual voltage demand of each piezo actuator. An allocation is made to a voltage demand category, which is included in the number combination on the injector.
These data items are transmitted to the ECM. During engine operation, these values are used to compensate for deviations in the metering and switching performance.

And yes, cars and trucks have the same requirements.

Dan

 

[c5vettster]

Regardless, this was my first experience with a common rail diesel repair. I daresay it wasn't all that bad. I am used to replacing injectors, replacing/rebuilding mechanical pumps. My experience working on this newer engine didn't prove to be more challenging or require any special tools. A simple backflow test told me which injectors were at fault, and swapping them out was a simple repair. I couldnt find any local indy place that would work on these engines, and the local Kubota dealer wasn't interested in making this repair.