Komatsu 3.6L excessive black smoke

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Komatsu 3.6L excessive black smoke

Postby alanhughes1973 » Sun Feb 16, 2014 2:41 pm

Came in smoking excessively ...found one injector defective.... filters changed.
Turbo intake was found to have rubber shavings after a flexible elbow installed.
Took turbo apart found lots of burnt rubber around shaft ....cleaned off . Bearing clean and no wear

Upon flash up , still excessive exhaust . ...

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Re: Komatsu 3.6L excessive black smoke

Postby JK » Mon Feb 17, 2014 6:29 am

Fuel/air ratio.
Most of the MFR manuals have a good troubleshooting section for their engines based on stack emissions.

But you want to run through the fuel system, injectors, pumps, rack setting, take cylinder pressures to see if you have an abnormals readings, ect.
On the air side what is the turbo putting out, what is going through the intercooler-set up a u-tube manometer, what is the turbo readings compare on history and so on.

Oh and check for bootleg injectors. They may have snuck into the ship stores.

Here is a list of some causes:
Incorrect timing
Dirty or worn injectors
Faulty turbocharger (ie not enough air to match the fuel)
Incorrect valve clearanceIncorrect air/fuel ratio
Low cylinder compression (eg sticking piston rings or worn components)
Dirty air cleaner
Restricted induction system (eg system too small or kinked inlet piping)
Other engine tune factors including valve adjustments, and regular servicing of air, fuel and oil filters. Do not buy fuel from suspect outlets.
Poor quality fuel
Excessive carbon build up in combustion and exhaust spaces
Cool operating temperatures

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D Winsor
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Re: Komatsu 3.6L excessive black smoke

Postby D Winsor » Mon Feb 17, 2014 11:41 am

Sounds like the rubber you found in the Turbo may have made it's way into the baffles of the after cooler.
Check the differential pressure across the Cooler with either a U tube Manometer or couple of pressure gauges If the differential is high it will be a good indicator that the cooler is choked restricting the air flow
Troubleshooting 101 "Don't over think it - K.I.S.S. it"

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Re: Komatsu 3.6L excessive black smoke

Postby astat101 » Wed May 13, 2015 11:56 pm


I am not sure if this will help at all but there is a company that manufacture diesel engine charge air coolers, you should try Vestas aircoil A/S in Denmark (

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Re: Komatsu 3.6L excessive black smoke

Postby JollyJack » Fri May 15, 2015 8:16 pm

We had a name for Komatsus, "Tojo's Revenge"!
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Re: Komatsu 3.6L excessive black smoke

Postby Merlyn » Fri May 15, 2015 11:13 pm

They nearly brought Caterpillar to its knees I well remember way back when, caused them a lot of trouble.
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

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