Hard to start

[jdoddharm]

I have a 2006 6.0 super duty, the last 2 days it has been cold and I can barely get this truck to start, any suggestions?

[Herb]

This could be due to gelling of the fuel, formation of ice in the fuel tanks or lines or poor fuel quality. Try using a fuel conditioner, (anti-gell/cetane boost), that will improve the cetane level and lower the gell point of the fuel, if you are not all ready doing so.

[Garfield78]

What was the air temp? Did you try the block heater? May be glow plug or intake heater problem. I don't remember what Ford has for starting, glow plugs or intake heater. Have you got synthetic engine oil in the engine? That sure helps in start ups. It will turn over alot easier. I had two batteries go bad on my D/A when it was 2 yrs old. The charging was fine.
Good Luck: Ralph

[jdoddharm]

It was around 30deg. I just started putting power service additive in the fuel, when I would crank it the engine would run for about 2 sec. and die then I would crank it again and it would do the same thing until finally it started and it knocked and rattled really bad and had no throttle response, then finally it cleared up and ran fine, I have noticed lately that when the engine is cold it runs real rough, that is part of the reason why I started adding the power service additive to my fuel.

[Nephir]

When the ambient temperature is low outside your engine is going to run rough, at least until you build some heat up in the cylinders to get proper ignition. I live up in Canada and both my trucks will start up until about minus 25 C which is about -15 F. Im pretty sure the for manual says you dont need a block heater until about -29C or -20F so I would be looking into things if you are having a really hard time starting befor those temps. Does it blow alot of white smoke during startup ? Possible glow plugs issues ? Restricted fuel system ? HEUI oil Leaks ?

[Errick Bodenheimer]

Have you checked you fuel pressure? It could be possiable that at lower temps that youre fuel pump is not putting out enough pressure! Put a gage on it a see! Has anyone done a injector buzz test on it ? Or a power balance test ?

[Ex Ford Diesel Tech]

The injectors on these engines are notorious for sticking in cold weather
(Ford calls it sticktion). Listen to the way the injectors rattle when you turn the key on on a warm engine. Then compare the sound when the engine is cold. If it doesn't sound similar It's probably time to replace all eight injectors. This is especially true on an engine with over 100k miles.
Hope this helps.