Hi All,

I'm particularly baffled by the behavior of 2006 E350 6L which has poor performance and stumbles when cold and is optimal when warm.

We checked the MAP and EBP hoses, glowplugs, EGR valve was changed being very dirty, the turbo was changed as well and we took a chance on the FICM and changed it as well. There is no DTCs and it still performs badly when cold. All is stock.

Does someone have an idea where we should orient our search, I have never seen a 6L so hard to diagnostic

Thanks, Mike

 

Do a search for "stiction". Very common with 6.0L injectors to have problems when cold. If you've tried everything else, you probably have some injectors needing to be replaced. The problems especially show up on engines with below average maintenance; extended oil change intervals and not keeping up on fuel filters.

 

Injector sticktion has my vote too.

 

What oil are you running? How long? What fuel filters? How long?

 

My 04 had the same problem. Ford flushed the system and the injectors
started working perfect. There is an aftermarket product for fuel injector
cleaning that supposedly works pretty well called Hot Shots Secret. Worth
a try. Good luck.

 

This is the first time I have seen a Positive post for Hot Shot Secret. But then the word "supposedly" is in the post.

If the OP would give info on the current oil as to weight and synthetic or not, that would help too. If the OP is running a non-synthetic and is ready to change the oil, I would suggest to go to a full synthetic CJ-4 rated oil. If he just changed the oil it would be just a well to add the Rev-X to the current oil. Many have posted results on Rev-X and I have seen some who have tried the HSS without any help and use the Rev-X and It would help on the cold start issues.

 

I had exactly the same problem for over two years and talked to the dealer until I was blue in the face! I had a loss of mileage and poor performance when it was cold. I asked all kinds of questions about why, about fuel, oil, and the only thing they said was use fuel treatment. This went on for over two years! They finally dug deeper when it took a turn for the worse and found out it was the head gaskets! No smoke or anything really to point to that. Very expensive fix though they didn't charge me for the twist they gave the knife in my back!

 

And YES! Did all the Ford recommended scheduled service!

 

more then lilkly an injector concern. watch power balance test when cold. should see some droping about -15 rpm or more.

 

Thanks for the input. It's a full synthetic oil 10W-40 that is used. There's been no concern to date with this engine. I told the mecanic to make a complete oil change anyway just to clear that matter.

Furthermore to this, I was just informed today that the truck has trouble starting when cold only, it takes about 15-20 seconds cranking. That would have been a helpful hint if I had known previously but nobody told me ...

I'll have the injectors checked out with an engine balance on an IDS, however what could cause this cold engine performance with this hard start ?

 

What brand of diesel oil is 10W-40? Also, as was said before, injector stiction (or oil latching) can cause your problems. Synthetic 5W-40 oil and the most recent flash update to the processors has helped many folks.

 

Thanks Bismic. The brand used is an european one (we do not have easily access to US oils) but all oils used here for such trucks are usually high quality brands for recent engines (Euro4 standard at the minimum) and also designed for heavy duty.

I have never run across injector stiction. Simply using a 5W40 instead of a 10W40 (less viscosity I take it) should help ?

Thanks,

Mike

 

Don't know if a 10W40 would be any less effective than a 5W40 - just not familiar with it. As I said, it needs to be CI4 or CJ4 rated.

STICTION
There is a 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. That spool valve 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. Mostly its a rough run cold condition but in severe cases it can be a no start or pretty harsh misfire condition. Oil that stays inside the 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 uses inductive heat 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 fantastic. It is an excellent preventative measure.

 

Ok, thanks. We're changing the oil to 5W50 according to spec. I'm having the unit sent to the dealership for more testing on the injection system, plus any update if necessary. I'll keep you updated.

 

Don't get me wrong ........... spec is 15W40, 5W40, OR 10W30 in a CI4 or CJ4 diesel oil according to the owners manual.

With regards to stiction, some people have benefited from the 5W40 switch. Others have had no issues with 15W40. It seems to be a case-by-case issue.

When you have stiction, it is worth it to try the synthetic oil and to get the flash update - better than hearing you need new injectors anyway.