Surge at Idle

[ARedmon]

I bought my first diesel a few months ago; a Dodge Ram 2500 4x4 6-spd. I love the truck so far but it does have one annoying habit. When I am easing off the gas while going uphill, once the gas is off, it surges forward. I almost ran into my garage door because of this surge. It is also a problem on my country one-lane road where there is a steep hill to crest. You must approach the peak of the hill slowly, just in case there is someone coming up the other side. When I get near the peak and let off the gas, the engine surges. It is hard to hold back that Cummins when it is getting fuel! The only thing you can do is act quickly to push the clutch in and let it rev before slowing back to idle. This problem is not life-threatening but it is annoying. Has anyone had this problem with their truck and how did you correct it?

 

[TSpecht]

I believe the problem is the engine doesn't like to see the RPM's drop below a certain point, and it increases fuel delivery in order to keep running at it's lowest preferred RPM level. In that situation it's best to downshift to a lower gear so you can keep a little engine speed. It's basically the same thing it does when you let the clutch out without giving it any fuel, it'll rev itself up slightly to allow you to take off from a dead stop.

To my knowledge there's nothing that can be done about it, since it's doing what it's supposed to, i. e. keeping itself running. The strategy to avoid it is to not allow RPM's to fall to the point where the computer thinks it'll stall if it doesn't increase power.

 

[cojhl2]

Had this problem in a serious way with a Class 8 once. Took it too a Cummins shop and they found the problem with something to do with the air control between the turbo and the pump. Has to do with Governor control.



I dont know how bad yours is,, but that truck of mine was almost undrivable,, couldn't shift or control it hardley.



Take it to a Cummins shop.