'98.5 24 valve 5.9 L ...
 

...CUMMINS w/ 155 K miles, 5 speed man, power puck, used to tow 5th wheel

during the final 45 minutes of a 2.5 hour run towing camper at highway speeds I noticed a need to down shift from 5th more often than usual to avoid "chatter" or "lugging"

Upon arrival I observed excessive white/blue smoke and a slight tendency to try and stall at low speed while maneuvering with clutch action. Hoping for fuel related issues I

added SEAFOAM to remaining 1/2 tank of fuel and watched as smoke cleared up and satisfied with that I shut it down. A while later when starting up again there was excessive smoke again, so I changed the fuel filter filling up the filter canister with SEAFOAM and after restart observed no smoke until the additive was displaced with diesel then the smoke returned. !?!

Had injectors and tubes replaced and valve lash set and oil change . smoke was greatly reduced but not eliminated. drained fuel tank of additive laced fuel and replaced with 5 gal fresh fuel. smoke would clear up but return when started again hours later this has been recurring off and on as final amounts of additive aced fuel is consumed then I put 3 more gal fresh fuel in and observed original excessive smoke once again after having been perfectly clear for 15 -20 minutes I'm now wondering WTF. Timing?

How long ago did you replace the air filter?

High pressure common rail pump losing it's oomph? What you are describing is exactly what the old manual injector pumps did when they were in failure.

...well, I don't like the $ound of that. I was hoping to unplug the power puck and see if the timing is messing up, that tuner is a 98 era and I wonder if the life span is spent, any thoughts?

...can someone tell me how to determine if my engine is a "non HO" ?

From what I know about the H.O. Cummins there were a few installed in the later 2000 models but they weren't advertised until the 2001 model year, and were only available with the 6 spd manual transmission. If someone has contradictory knowledge I will bow to their expertise and stand corrected.

I believe the HO engines weren't advertised as available until 2001 and they only put them in front of manual 6 speed, although I have read of a few that got into late 2000 models.

...Thanks guys! now... does any one know how to grow a money tree?