cummins isx 500 backfire normal ???

Backfiring on a diesel????
from the exhaust, or intake?
DPF system? (on an 08?)
Sticking valve or broken spring?

So you are keeping it above 1500 to prevent popping?
It it one pop or a regular event like one cylinder misbehaving?

 

Is it more of a fast "WOOSH" sound? Mine dose this every so often. Was told it has something to do with the EGR. Mine was replaced once and it stopped for some time but its starting to do it some again. The truck dose hesitate when it happens. It feel like it loses turbo boost for a split second. Mine is an 07 without the DPF.

 

I've had the problem in a Detroit 60 which seemed like back firing but was actually fuel some how being sucked in and combusting in the turbo itself. Odd if you ask me. Didn't keep the truck long after it started doing it so I don't know the out come of it. It had a sudden loss of power and acted like kinda like shifting with the jake on but that wasn't what was going on.

 

has the check engine light been coming on???

 

I have a 2010 ISX 450 and if you are pulling down low you better be easy letting up on the throttle or it will do it. If it's doing a regen going down the road it's worse. Be very gentle leaving up on the throttle and it won't do it. That's been my experience.

 

Are you referring to the fueling hesitation and turbocharger "gurgle" at around 1200 rpm during a regen? If so, it's normal. However, there is a new calibration out (I believe it's Sept. or Oct. '10) that is supposed to address the issue and minimize the effect. I've had two of mine updated to the new calibration, but have yet to experience a regen to see if there's a difference.

 

I have heard similar noises coming from my cummins engines both dpf and just egr. I believe that it is the turbo going into a stall wich is a result from boost pressure being higher than drive pressure and momentarily spinning the turbo backwards. Just my thoughts.

 

my 07 pete was doing the same thing for 2 years and our monkey wrench couldn't figure it out until we had a t 800 kw apparently doing the same thing so then our parts changer dove right in and must have found the problem because mysteriously my pete hasn't backfired since. And in case you were wondering yes our parts changer is a k w man. and he still hasn't told me what the problem was for sure but I think it was something to do with a tube or line from the turbo to a sensor somewhere. I will try to do some more investigating to get you the answer to your question