Smoke on acceleration

[Montemar]

I have a Tamd41b recently rebuilt with the injection system reconditioned by Bosch. Apart from a small niggle now fixed the engine has run perfectly. Now it produces dark grey smoke on acceleration that persists until the speed levels out. Accelerate further and the smoke is produced then stops. This all starts from 2000 rpm.
the port engine continues to work perfectly.
Any suggestions most welcome.

 

[lusitano]

Pump timing likely

 

[burgundyben]

Dirty bottom?

 

[Montemar]

Thanks but is only one engine that does it

 

[Portofino]

Pump timing likely

Yep .
Always go back to the last thing meddled = pump = fuels too rich .

Either a fault , possibly but unlikely from Bosch .
Or Counterintuitively its momentarily when you say “ accelerate “ because it’s the good un now so to speak having to work harder to cross compensate for the weaker un serviced pump engine .This manifest itself with a short overload the smoke until the other weaker has caught up .Then it settles down back to normal.Which is what you see .

 

[Montemar]

Thanks for replies.
Have done tests on each engine independently and starboard only shows the smoke.
Engine originally blown due to leaking aftercooler which was replaced. A further aftercooler leak fits the bill as original port unit fitted and new unit fitted to port.
So it is 32 years old and will check it manana. It fits a lack of air problem. Can’t believe it is a fuelling problem as whole system was Bosched during the rebuild.

 

[Portofino]

Thanks for replies.
Have done tests on each engine independently and starboard only shows the smoke.
Engine originally blown due to leaking aftercooler which was replaced. A further aftercooler leak fits the bill as original port unit fitted and new unit fitted to port.
So it is 32 years old and will check it manana. It fits a lack of air problem. Can’t believe it is a fuelling problem as whole system was Bosched during the rebuild.

Ah goal post have just moved now you toss in after cooler woes ……but I did say “ go back to last thing meddled ….”

 

[QBhoy]

Sounds like fuel, must admit. Were the injectors replaced or serviced and pop tested to the correct opening pressure ? Check the engine oil for signs or smells of diesel. Or perhaps she’s running cold and combusting conditions aren’t ideal.
Could she just be burning off the remains of any deposits left by her previous health state ?

 

[Montemar]

Many thanks for replies.
Last thing done was complete rebuild and fuel stuff sent back to Bosch for reconditioning.
ot is either too much fuel or not enough air.
I will check aftercooler tomorrow and see if there is a water leak.

 

[Montemar]

New air filters fitted to both engines in Spring this year.
Removed air filter on starboard engine and smoke virtually gone. Port engine continues smoke free.
If I rev the SBD engine up to max it pushes out a black cloud and a film of fuel (presumably) left on the sea. Port engine is clean when revved up.
Reconditioned turbos fitted to both engines August 2019.
The SBD engine was completely rebuilt late 2021 so how can it perform worse that the original port engine?
Any input gratefully received.

 

[al terego]

One of the joys of having two identical engines is the ability to swop parts .......... turbo, pumps etc.
I have two AD31's with the exact same problem as you, with one of them smoking badly on acceleration. I've tried all the easy solutions - new air filters, fuel filters, injector cleaning liquid, new exhaust elbows, cleaned aftercooler, turbo spinning and sprayed, props clean and not slipping. Next is to send the injectors away for testing/cleaning. If that doesn't work then I'll swop the fuel pumps over and then the turbos.

 

[Montemar]

I removed two injectors and had them checked - both ok. I will get the other four done as a precaution. I don’t know where you are but Morey Diesel in Bridport are very competent and helpful. Did mine foc.

 

[Montemar]

Check the plastic pipe between the metering unit and the inlet manifold for cracks or leaks.
If the diaphragm in the aneroid sensor on top of the metering unit is dective this can also cause your problem