Started my truck the other morning. It was about 7*F - truck was not pluged in. Once the truck fired it went right up to 1000 rpm and ran ruff for about a minute or so. After that time the ruff idle went away and it ran smooth at 1000 rpm not much smoke. Is this normal? I thought I heard some one say that these engines run on three cylinders when its a cold start... Maybe I was hearing things....

Tim

 

Normal operation when cold. Does not run on three cylinders.

 

My 02 would shutdown 3 cylinders when it was really cold out... don't know if these newer ones do that or not...

Tony

 

How do you know?

 

It would go into high idle and then if it was really cold out, the engine would make a completely different sound after a minute or so of high idling, almost sounded like when the exhaust brake was on...

Here's the TSB for that: http://dodgeram.info/tsb/2001/18-019-01.htm

and here is a quote from it:

"Additionally, if Intake Manifold Temperature (IMT) is less than -9°C (15°F), and all of the parameters above are met, three of the cylinders will be shut off upon reaching 1200 rpm, creating a slight change in engine sound which is normal. This allows the engine to create increased heat in the cooling system, allowing more rapid engine warm up and cab heating."


Tony