Rough idle

[the cable guy]

06 6.0 55k
never had a problem until now, except EGR at 30k cleaned it and its been fine.

getting colder on the east coast lately, rough idle on cold start in the am. Sounds terrible for about 10-20 seconds then smooths out. Is totally fine after that. Pull out of the driveway and its runs like it always has. Only after it sits all nite. Can sit for 5-6 hrs during the day and it starts fine.
Dont want this to be a prob as it gets real cold

2 wks ago changed oil and fuel filters and run a fuel additive in the fall and winter time.

I am aware of the TSB about cold start but never had the issue until now.

Spoke to local dealer and they want to look at the truck and determine if any of the TSB's are for my VIN #, then possibly reflash the computer thurs and cold start it fri morning at their shop to see if it fixes it

sounds legit to me any other thoughts? FCIM? glow plug circuitry?

 

[bismic1]

What oil do you use?

New flash should help.

Are you sure the batteries are healthy? Have you checked the FICM voltages?

 

[02Oilburner]

Plug your truck in tonight and see if it runs rough in the morning when you start it. Might need to check glow plug relay also. Stealership will rip you a new one!

 

[the cable guy]

oil I use id rotella 15w/40
Battery connections are clean, 2 yrs old
I have not checked any voltages on the FICM

I will plug it in tonite and see, since it only happens after it sits all nite I expect that the block heater will eliminate the AM symptoms.

since its 2006 with 55k its under warranty for this stuff according to my paperwork.

 

[bismic1]

You do not want to "encourage" sticition to develop. Depending on the ambient temperature, a 5W40 would be a better oil year round. A 10W30 would be better for winter, but I am not a big fan of it for towing heavy or extreme summer heat.

I would switch oils personally, but since it is under warranty, taking it in is probably the best route. Make sure you get the latest flash update. You will most likely get stuck w/ $100 deductible each time it goes in, UNLESS you build the case that it is EMISSIONS related (then no deductible). Look up your emissions warranty coverage in your owners manual and don't let them keep hitting you w/ that deductible charge.

BTW:

The 6.0L injectors are totally reliant on two electromagnets to shuttle the spool and control the oil to the injectors. The 7.3`s use an electromagnet also but they also have a spring to return the poppet to the closed position. Obviously the spring will work much better to "cut" through the thick oil and close the oil flow.

The small spool valve in the top of the injector that controls the flow of high oil pressure fed to the intensifier piston in the fuel injector only moves .017", back and forth, on and off every time the injector fires. Many factors play in to how well that valve works such as, oil temp, oil quality, normal wear, ambient temp, and many others. As this valve ages it polishes itself inside the bore of the spool valve and as the spool valve slams back and forth it can set up the condition like a suction cup, hanging the valve to one side or the other. This uncommanded uncontrollable condition is called stiction or also called oil latching. Mostly its a rough run cold condition but in severe cases it can be a no start or pretty harsh misfire condition. Not only will running oil with too thick of a viscosity cause rough starts, but this also will interrupt the shuttle action of the spool causing injection timing to be retarded causing poor performance and decreased mileage until the oil is up to full operating temperature. It can also cause poor combustion and coking in the EGR components and the turbo.

Oil that stays inside the spool valve on a hot engine shutdown and is allowed to cool slowly in the injector can aggravate the condition on restart, so the newest reflash (calibration update to your truck's computer(s) uses inductive heat (remember your FICM is a DC-DC converter that steps up your 12V electrical supply to 48V) after shutdown to keep the oil warm, keep its viscosity low, and maximize the oil flowability to purge the oil from them. It has worked very well. It is an excellent preventative measure. The newest flashes addresses improved troubleshooting of FICM and related components, but also include some adjustments to "ease" the electical strain produced on the FICM.

 

[the cable guy]

thanks for the excellent theoretical breakdwon of the injector system.
oil viscosity may be a issue here.
I wonder if i should remove the 2 wk old 15/w40 oil and drop in some rotella syn/blend and see what happens?

What effect does a reflash have on the overall engine performance?

this 6.0 runs great has excellent power and good milage

will replace oil with rotella T6 synthetic tonite and give it try in the AM.

 

[the cable guy]

Changed to Rotello T6 syn 5/30 and the symptoms on AM cold start are much better, A slight chug for 2-3 sec when started today at 30 degrees.

would that be considered normal? or should I get it reflashed?

 

[the cable guy]

Took it to the local dealer, They said there was a stored code and FICM was the issue. They replaced it under warranty.

I will let you guys know how it goes
thanks.

 

[the cable guy]

This morning 18 degrees, started without any issue. Sounded great aand had power right away. The noise that I usually hear when wait for the glow plugs to warm is different. The new FCIM and re flash makes a huge difference.
Good luck guys

 

[bismic1]

Glad you got it taken care of.

BTW - the FICM is covered under the emissions warranty - ZERO deductible!