ISX fuel slobber

Are you sure that is fuel and not oil?

 

If it is really fuel you have some kind of injector related problem that needs immediate attention in my opinion.
I thank it is more likely oil. Probably passed by the rings but and or some valve stems. That to me is not really a problem but more of an irritant. If you do not have excessive blow by and or oil consumption I would not worry about. Just be irritated like you are. Try setting the idle at different speeds between 900-1200 and see if that helps.

 

"With their large cooling systems and the vast amount of air that passes through them during idling, diesel engines tend to run cool. The typical results of burning fuel in a modern diesel engine are about 67% nitrogen, 11% carbon dioxide, 11% water vapor and 9% oxygen. Less than 1% makes up all the “bad” pollutants that diesel exhaust has recently become so infamous for. On a cold start of a diesel engine, the water vapor may be cold enough that it turns into liquid water in the exhaust system – especially on trucks with vertical exhaust stacks. This liquid water can run back down the stack and leak at various clamped joints, making a mess on the chrome elbows, and possibly even leak out of the flex pipe.

This “fuel slobber” problem normally goes away in just a few minutes if the truck is put to work, but if it remains idling, especially on a cold day, the liquid water can be quite a nuisance. Most of us believe that this liquid water is not good for modern diesel particulate filters, especially if the engine is shut down before it gets hot enough to turn the liquid back into a vapor and purge if from the filter. This “slobber” can also run out of the exhaust manifold at the connecting joints and run down the side of the engine. If this happens, just spray the slobber with soap or penetrating oil and wipe it off with a rag (many penetrating oils are also very good cleaning solvents that will also help to keep the engine from rusting)."

 

That is interesting but also looks like an add. My personal experience is that cylinder is normally passing oil. Pull the manifold. If the above listed is the case all cylinder exhaust ports should be wet.
Possibly that is the only cylinder that the manifold gasket is not totally sealed on?
Just open conversation not casting stones.

 

If your sniffer is not working so good try the paper towel test. put a few drops of the liquid on a piece of white paper towel and if there's diesel fuel in it it should leave a halo around the spot.
The cm870 I have started to leak oil out of the back of the exhaust manifold. It would soak the engine. I would have to add oil every day.

When I finally took it to the engine mechanic he took the turbo and the exhaust manifold off and capped the coolant & oil lines and fired it up.
Engine oil was coming out of piston number 2 port.
After tearing it down they found that a piston ring on the #2 piston had failed.

 

This my cm870 has done this even after my rebuild with new head,pistons,liners,rings,bearings