How to get a Cummins to pull properly

I wouldn't want to see the fuel bill driving like this. These engines are designed to be run down to 1000 rpm before grabbing the next gear. If it will maintain speed at 1000, you should hold it there. Do you have a good reason for running your rpms up like that? You're wasting fuel and sacrificing long term engine and emissions longevity. I have a 2012 truck with an ISX. I don't care if you have 600 hp, if you weigh 80k and are trying to get up a 7% grade, you won't get anywhere fast. Don't fight with gravity.

 

You pull these down to 1000 rpm's before grabbing a gear and you can bet your sweet bottom dollar you'll be putting liners in that engine way before it's time. They're not a tugboat engine.

 

Almost 600k and it doesn't use oil. One gallon per 15k miles. I only run my engine at 40% engine load during a hard pull. How low you'll take you take your motor will depend on how much power you demand. By demanding lower power you increase engine and emissions longevity. The Cummins in my truck makes full torque down to 1200 and makes the power I need to 1000. My needs are different in that I don't care about speed or power; I only care about maximum MPG.

 

Wow

 

Smaller tires would pull hills better.
Or change the gear ratio

 

You sure you don't have a Maxidyne engine and not a Cummins? (just being humorously sarcastic, don't mind me at all...been a long week with my Signature 600 screaming in my ears at 1600 rpm's all day and night, pulling mountains up through Pennsylvania in the passing lane mostly...lol.) and still getting 6.2 mpg.

Sorry yellow motor guys, it's either you HATE these red motors or you LOVE them, there's nothing in between. I just got lucky and got an exceptional one I guess. 850K miles and strong as an ox still (knock on hardwood...my head actually.) I have two older 3406's that I adore too, but they ain't no first gen ISX in the hills.

 

You might be able to re-rate it to 600?

 

This is one of the best answers you will get. I have isx engines in all of my non-Mack trucks and every one of them has the automotive governor set to yes and they were all dogs. They were changed to continuous and now are drivable. The automotive governor setting I was told by the Cummings rep was to ensure the drivability by those who are not truck drivers, mainly rv and "steering wheel dummies".

On the four trucks with isx engines I drive for customers, there are two that are set automotive and two that were changed to continuous. The former trucks are driven with the r's up between 1400 and 1550 while the latter trucks you can pull under a light load from idle to 1600 without problems and a heavy load from the peak torque - 1200 to 1600.

I know many of you think you will screw up the engine by pulling at idle under a light load but you won't. The fuel system adjusts to this and the days of high r's seem to be in the past.

 

Not to high jack the thread, but our cm2250 and cm2350s will sometimes encounter a "dead throttle" after shifting into 18th on a pull. After roughly 3-5 seconds it will start to fuel again. It will not allow you to re engage the cruise until the 3-5 seconds pass either. Does this have anything to do with the throttle governor or is it a separate issue?