'06 Very Rough Idle and smoke at start-up

[JPearcey]

My '06 has developed a very rough idle and smoke problem at start-up. (Happened at 20K miles) Smoke is blue /white and clears up after 30 - 40 seconds but rough idle stays until engine warms up. The truck actually shakes as a result of the idle. If you throttle up right after start-up both the smoke and the rough idle clears more quickly - let off the throttle and smoke is usually gone but rough idle only improves a bit. After engine is fully up to temperature both problems seem to fullly disappear however there may be slightly more "knock" then when truck was new. This happened before (at about 12000 miles) but lasted for only about a week... then the problem went away.



The interesting thing is that both times this problem occurred it started after I had turned the key "on" but did not start the engine right away (left in on position for at least a minute, maybe more) then when the engine started rough idle happened... I assume there is a preheater / glow plug on this engine... could the heater not have cycled off and burned the cylinders/nozzles???? Anyone else leave key on and experience same problem????

 

[RMalone]

Off the cuff it sounds like an injector or bad fuel issue. I doubt the intake heater (no glow plugs) would burn anything, it is located right at the base of the intake horn.

 

[DOWG]

I installed some of Dynomite Diesel's 50 HP extrude honed injector nozzles. I like the power, but I was absolutely amazed at how much smoother the Cummins idles now.

 

[SDunkle600]

JPearcey,



I had a similiar problem with my 04. 5. After much research, I concluded that it was carboned injectors. I don't know if you do much towing or tow very heavy but these trucks love to be run. Using Sea Foam, I drained the fuel filter canister, filled with Sea Foam, started it and ran for a minute then shut it down for 10 minutes and then fired it back up and ran it like I stole it up the mountains near my house. It definitley cleaned up the injectors and the knock and rough idle were both gone. I run power service (grey bottle) w/ MMO now to try to keep everything cleaned up.

 

[FLynes]

I don't know if this is the problem with yours, but my 05 did the exact same thing. I took it in to the dealership and found out there was a TSB on the programming with the injectors. They reprogrammed the ECM and everything is now working fine.

 

[wcjp]

I installed some of Dynomite Diesel's 50 HP extrude honed injector nozzles. I like the power, but I was absolutely amazed at how much smoother the Cummins idles now.

My Mega had about 4k miles when DDP did the injectors. DDP sticks also smoothed the idle. I also run Powerservice sporadically and tow at least once a month. This probably helps keep the injectors clean.

 

[TSPowell]

I'm having the same problem right now with my 04. 5 Went out one morning tried to start it, just cranked and wouldn't start. Unpluged the TST, but still just wouldn't start. Finally put the go-pedal to the floor and finally started but ran really, really rough. Unitll the thing warms up it idles like crap. So I ran the fuel tank to empty, put two cans of sea foam in yesterday and will see what happens. If anyone else knows whats going on, please tell us. If its the injectors, I too am going with 50hp ddp sticks!

 

[JGheen]

Using Sea Foam, I drained the fuel filter canister, filled with Sea Foam, started it and ran for a minute then shut it down for 10 minutes and then fired it back up and ran it like I stole it up the mountains near my house. It definitley cleaned up the injectors and the knock and rough idle were both gone. I run power service (grey bottle) w/ MMO now to try to keep everything cleaned up.

What is Sea foam? Never heard of it

Also, I run the Diesel Kleen at every fill up as well but what is MMO? Sorry, I don't de-code abreviations that well.



Joe

 

[Smokin Joes 2500]

I installed some of Dynomite Diesel's 50 HP extrude honed injector nozzles. I like the power, but I was absolutely amazed at how much smoother the Cummins idles now.

I too had the rough idle and blue smoke syndrome... INJECTORS... #1 &#5 were both cracked. I had a set of custom (local diesel shop did them) 50 horse nozzles installed, WOW power, smoke, smooth idle (also had the valves run through, obviously with an injector swap this is necassary but I attribute this to a smoother idle and quieter motor too) Just my . 02 have the injectors checked mine went bad with only 13,000 on the ticker :{