Losing power/RPM's - Cummins 6CT450

[CaribbeanCruzer]

Port engine appears to run fine at the dock but will not power up under stress. Bogs down, loses power, and will not maintain RPM's. Currently 600 hrs. on engines.

Replaced racors with no change. I'm planning to replace the secondary fuel filter next but I suspect I may have a bad injector or perhaps an injector seat leak. The on-site mechanic suggests that it may also be caused by a fouled-up turbo (around the small fan blades). I also noticed that oil is now seeping from the air filter.

Any ideas or suggestions on where to begin? Thanks very much.

 

[CaribbeanCruzer]

Same, only worse. Installed secondary fuel filter hoping for an easy fix. Of course that would be way too easy though. When I cranked the engine, black soot blew out. Thenk at idle it seemed to run okay. But at higher RPM's smoke poured out consistently. I immediately shut it down.

After another brief phone conversation with the on-site mechanic, his first guess is that the turbo charger is fouled up, partially clogged and not spinning, and is not functioning properly. He suggests it may need to be cleaned out. Update: not the case. Turbo fan is good and clean, spins fine. The inside of the air filter (mostly the housing where it mounts to engine) is loaded with dark gray colored sludge.

Before I start pouring money I'd love to have somewhat of an understanding. Never know, I may be able to knock this one out myself. Should I also be concerned about the injectors? Any ideas or suggestions will be greatly appreciated. Thanks.

 

[Skip]

You have indicated that the turbocharger vanes spin freely.

That does not mean that the turbo is adding boost as RPMs increase. If your 6CTAs are like mine, there is noticeable turbo lag between 1500-1900 RPMs. At 1900 the turbos spool up and the accelration is dramatic up to 2450-2500 RPMs. Acceleration flattens out over the last 150 RPMs to WOT (2650)

So--can you hear the turbos starting to wind up? Are the hose clamps tight on the outlet side of the turbos? I broke a hose clamp on the outlet side of the starboard turbo and it seemed as though we had tossed an anchor off the starboard side of the boat..the glendinning synchronizer would not stay engaged, which was the first clue.

 

[earthmover17]

You seem to be fixated on the injectors. I would concentrate on the Turbos as was said before. Just because they spin freely does not mean something else hasn't gone wrong. Troubleshoot them completly before moving on to something else. Everything you describe sounds like air starvation. As the previous poster said there could be a clamp broken, or a bad gasket so you need to make sure the Turbo is spooling up.

Jack