Hi all,

Well, it's one of those that needs some of your insight. We have here a 2006 6.0L with an ongoing issue of hard start poor performance when cold, and a real happy engine when warm, with about 58000 miles, all stock.

On this truck we changed the EGR valve, turbo (both not looking very nice at the time) at the time and the FICM was checked, all updates done. By the time that was done, the truck was released for duty and a few days later came back with a stiction problem on one injector, which was changed and all looked ok.

Then it came back a few weeks later with a no start when warm. It was diagnosed with a HP leak so we changed the STC fitting, both rails on each side and the EGR cooler for good measure.

However, the drivers had not told us that the hard start/poor performance status had remained unchanged. After releasing the truck once again for duty, the mecanic telling us that all was ok, we're back at point 1, there is still this hard start/poor performance when cold only. The mecanic checked the truck before relasing it and had no issue with it when cold !!!???

Before losing more time in trying to diagnose everything, and besides the turbo, FICM, EGR, injectors which all look ok, where should we orient our search ? There is no DTC's on the truck, no codes which show up on ICP sensor, glowplugs, etc. Could it be feasible that we have a oil viscosity issue with this specific unit as the mecanic seems to be using a high quality synthetic 15-30 oil. I read some time ago that some are using an additive that seems to improve things in this area, especially related to stiction. Could such a product be of any benefit ?

Thanks for your input.

 

Where part of the country does this truck operate? Rarely hear of anyone using that viscosity of oil - syn or not. A lot of us use 5w40 syn. My preference is Rotella T6. Wouldn't cost much to switch oil and maybe find the answer to your problems. Make sure you are only using Motorcraft, International or Racor (actual manufacturer of the other two) filters. Other brand of filters have been linked to major engine problems.

 

you more then likly have injector stiction issues or a failing ficm.

 

Thx for your answers. We're in Switzerland. The mecanic checked the injectors for any stiction but they seem to run ok and we only use Motorcraft filters.

I'm thinking of all the following to be rechecked as well :

FICM, as you say Cheezit
ICP
Glowplugs
Oil grade

Can a fuel issue cause such a problem ??

Thanks.

 

I would say check fuel pressure also--can't hurt a thing.

 

fuel if its gelled. dont know how cold it is there right now.
thats easy enugh to test just use a 5 gallon supply of fresh fuel insted of the tank.
whats it do with the block heater pluged in?
its very hard to chatch stiction in action if the pcm does not see a negitive crank swing. so basicly if all the injectors suffer from aporx. the smae amout you wount see it on a scan tool because they all be even.
if I remeber corrrectly you guys are running truck chasis. you may just have to install 4 new injectors on one back and see if that makes a differnece. no change dont wast the time on the other bank. if theres a change then you would replace the other 4.
sometimes it just comes down to that.