I learned about diesel back when they used to be all mechanical.

You used to leave the truck running because starting and shutting off the engine was bad for your injectors not to mention batterys and starters.

Is this still true with these ctd`s with computer controlled motors?

And if you`ve been driving awhile and finally come to a stop where your going to shut off the engine can you do it right away or should you wait a few minutes to let the turbo cool down ?

Thanks, Bob

 

You don't want to do extended idle times unless you enable high idle, these engines cool down too far on low idle and you end up with an incomplete burn causing cylinder wash. That means fuel in the oil and that is not a good thing.

Not good to turn off a turbo hot it will coke the oil in it causing you bearing problems at the very least. If you have been working it hard let it cool a few minutes before shut down, if you are just cruising usually by the time you idle around a parking lot looking for a place to park it cools down enough to shut her down.

 

You need to let the motor idle for a minute before you shut down to keep the oil from coking in the turbo. If you read through your owners manual, it will tell you how long you should wait depending on the load.

I usually wait until my EGT's are down to 300*. If I've been running it hard, I let it cool down longer.

As far as not shutting it off for short stops... I used to not shut my truck down, but with the price of fuel... also, look at the UPS guys, they shut their trucks down at every stop.

If I'm running in the gas station for a coke, I'll leave it running. Anything longer than that, shut it off.

 

I`ve misplaced it. How do i enable high idle? and unalbe it?

Do i want high idle at startup or let it do it`s normal thing?

 

If it's cold enough (I believe 15-25*), it'll do it immediately upon startup. If it's slightly warmer it will idle a bit like normal, then jump up to about 1k or so.

Do you have Auto or Manual? If you have auto, you can use Smarty or go to the dealer and have it enabled. If it's manual it's a bit more in depth... if you have an 03 or early 04 it's not likely you can have it and you'll have to do it mechanically (wooden stick on throttle).

-J

 

with 5.9 , only get down to low 40`s

 

You might run into the cold weather idle, not entirely sure, but I doubt you'll run into the immediate fast idle but I'm not sure how cold it gets at night there.

With an 06 I *think* you can just put a Smarty on your truck and it has the cruise control high idle enable built in to the software. Otherwise I believe you can go to dealer and have them enable it for you (might cost a few bucks, I have no idea first hand...).

That is assuming your truck is automatic.

-J

 

The dealer can do it, but it might already be installed. With the truck in park and running, turn on the cruise control, then hit set. If it idles up to 1100, you have it. You can adjust the idle up or down from 1100-1500 with the acel/decel buttons.

Owners Manual:
http://www.dodge.com/en/owners/manuals/

Smarty has it built into the stock software, I believe.

 

Yes it is an auto

 

As usual , you da man.

 

Nah, just tryin to be like you, buddy.

 

I was told by a factory Cummins trouble shooter, that they send all over the world to fix problems, that even high idle will not cause enough of a load in order to keep the cylinder temperature high enough to prevent cylinder wash.....I have an 04 automatic and it has high idle enabled......you will need to have a dealer or have a Smarty to have this done.

 

I let my EGT's cool to 350. I was waiting for them to get below 300 but in the summer that can take well over 3 minutes, and now what about cylinder wash?

They drop below 350 in under a minute.

 

In the summer if the A/C is on my EGT wil not drop below 350.

I also have a cool down timer and I use it to make very short trips from the truck. If someone tried to take the truck will it is running it will shutdown when the e-brake is released or after 2 to 6 minutes it will quit.

 

The cooling system on these trucks are huge...hence the need for winter fronts in cold climates.

Without high idle activated in cool temps, you run the risk of incomplete combustion like already stated.

High idle will also help in the warm weather with A/C performance as well.