Hello I am new to this board. So far I am impressed with the questions and the responses vs. "some other" boards.

I recently overhauled a 6.9 with all new internal parts. Problem is it has thick lingering whitish/grey smoke a small amount at idle and LOTS of it with an increase in RPM's once it is warmed up it is really bad.

I have removed the injectors and disassembled them and thoroughly cleaned them. They are not too old. Checked for air leaks and tighten fittings. The IP probably does not have more than 5,000 miles on it since it was overhauled but a diesel shop in Boise.

I was careful about the timing gear alignment and have tried several dimes witdth before and after the center mark on the IP . It is slightly better 4 deg advanced.

I have not changed the fuel filter yet but it does have fresh fuel in the tanks. I use these engines on irrigation pumps on our farm and overhauled them in the past all with out this problem. This is the first one in a truck however. The truck sat for a couple of years and that is the reason for the flush and fresh fuel.

I really like these engines and have gotten 1,000's of hours out of them. But his has me stumped. It starts right up on about the 3rd crank after the light goes out. And has plenty of power. Except for going into stealth mode (smokes so much it would just about be hidden) it runs fine. The smoke does NOT have the typical sweet smell that you get from coolant burning. I have had LOTS of experience with this. I have a couple of diesel tractors that eat head gaskets.

I am a pretty good mechanic as being a small farmer kinda requires it. But this has me fooled. I would just about pee on a electric fence to get this fixed!!!

Sorry this is so long and thanks for any help.

 

Have you pop tested the injectors? Sounds like a leaker or two. Or retarded timing on the pump.

 

If the white smoke smells like fuel my first guess would be a couple leaking injectors.

Before you pull them, get a new fuel filter and a bottle of Diesel Kleen.
Remove the old filter and fill the new one with the Diesel Kleen, then install it.
Start the engine, let it run 15 seconds and turn it off.
Let it set for a couple hours, then start and let it run for a while.

Did you service or replace the CDR while you were rebuilding the engine?

 

I would pull the injectors and get them tested first. If they test fine then it has to be the injection pump.

Rebuilt pumps are not generally completely rebuilt. They replace faulty/worn parts and slap it back together, the rest of the pump is original.

My neighbor just went through this on a cummins. Injector pump was bad, replaced with a rebuild (over $900) and 3 weeks later the injector pump started acting up again but differently than the first one. Under warranty but still a pain.

 

Unknown last filter change date and has been sitting for a while was my reasoning for the filter change and Diesel Kleen before anything else.

A clean filter and the IP cleaned and lubed by the Diesel Kleen may fix most of the problem.

If it has to be running soon as possible, pop test first may be a good idea.
But if it is not needed right away, I always try the cheaper easier things first.