Hi, guys. Is regeneration initiated by vehicle speed, engine RPM, or both? The reason I ask is that I frequently drive at slow speeds on some days but I try to make sure my RPM's are around 1500 or above. So, let's say the truck's traveling at around 20-30 MPH but the RPM's are fairly high. Will regeneration take place under these conditions?

As far as the high idle goes, if i set it to 1500 RPM's even though the vehicle isn't moving, will it still regenerate?

Thanks in advance for your help. I'm still learning about my 1st diesel....

 

Personally I don't think the high rpm is going to make any difference. I know on a forced regen on a "lightly" used truck can take as long as 20 to 50 miles to get the delta readings on the DPF and the SoX #'s down to an acceptable level. I have one to do tommorow that has not been updated since "AP" and has lived a life of a soccer mom station wagon maybe pulling a toy hauler every other month. This particular truck has an average mph or 22mph. Mileage divided by engine hours will give you an idea of how the truck is operated.

My advice is to make dang sure your ecm and ccn are updated to the latest greatest flash level, and do not increase your high idle. Simply set it and let it increase to the first level. Increasing it higher with the "accel" button will take it out of the net zero idle strategy and create more soot......or at least this is what i was told. It was my understanding that they were going to eliminate the idle "increase" with the accel button for this reason.

 

What I have seen is that it will do a regeneration around 30 MPH if you keep it over 1500-1600 RPM. However if you do this all the time you need to get out on the highway as much as you can to keep it clean as a higher RPM at a faster speed (55-65) will clean it out better (soot will slowly keep building if you don't run it hard even if it does a regeneration, it needs to be the long one not a short one all the time).

 

if thats a manual tranni,i run and drive it at 2200 to 2400 before shifting and driving around town i keep it at 2200 rpm its been 3 months and no ckeck engine light i think the higher rpms keep it runnin cleaner.

 

Thanks for the help, guys.

J Body: (Quote) "My advice is to make dang sure your ecm and ccn are updated to the latest greatest flash level..."

I know what the ecm is, but what is the ccn?

 

CCN cabin compartment node.....stupid acronym for the cluster. IF you have an 07 the ccn can be updated to display messages pertaining to the DPF. Change is outlined in a TSB I'm too lazy to look up right now. Comes with the niftly lil DVD/CD/decal explaining the DPF process and the messages you could possibly see.

 

Thanks again, guys. I'm really learning from reading these threads!

Now, let me get this straight once and for all: from what I understand regeneration can only take place when the vehicle is actually moving (at a certain minimum speed) and NEVER takes place while sitting still and raising the idle. Is that correct? If so, my question has been answered. Thanks....

 

I am assuming mine will regen while idling because I have had the hair burnt off of my legs when walking within about 3-4 feet of my tailpipe, unless this -is something else.

 

This is copied from the latest flash available. Straight from the TSB.

B. ISSUES IMPROVED SIGNIFICANTLY BY VARIOUS ECM SOFTWARE RELEASES
TO DATE:
NOTE: The following symptoms and conditions have been significantly enhanced by
the latest ECM software listed in this Service Bulletin. Always check
TechCONNECT to see if there are new or additional Service Bulletins that
may apply to a condition.
1. The latest ECM software includes a new extended idle feature to accommodate the
extended idle times present in some duty cycles. This feature may help to reduce the
accumulation of soot in the exhaust aftertreatment system when the engine is idling for
an extended period of time. Briefly how this feature works:
18-013-08 REV. A -2-
a. As needed, the engine enters an idling mode which dramatically reduces the rate of
soot accumulation in the diesel particulate filter (called “Net Zero”). Further, under
extended idle periods of **5 minutes or longer**, the engine enters a mode which
reduces the amount of soot accumulated in the diesel particulate filter (called “Net
Reduction”). While in these modes, the idle speed increases to 900 RPM for a
period of time. The idle speed may return to normal idle speed and then return to
900 RPM to repeat this cycle during very long idle periods.
b. **These modes occur automatically depending on the need to regenerate the DPF
as long as the vehicle is not driven over 20 MPH or operated at high load. If the
vehicle is driven over 20 MPH normal mobile desoot will occur automatically.**

 

"While in these modes, the idle speed increases to 900 RPM for a
period of time. The idle speed may return to normal idle speed and then return to
900 RPM to repeat this cycle during very long idle periods." (quote)

Couldn't I accomplish the same thing by manually raising my idle speed with the high idle feature? Why is a new flash necessary? Thanks in advance for the explanation...

 

Probably the best operating conditions for a regeneration are usually on the highway with the rpm at around 2000. I usually put it in 5th (on an auto) and set the cruise with the rpm at 2000 (about 65mph) and let it do it's thing.

 

I suppose 5th gear in an automatic is about the same as 6th in the manual, so running in 6th at that speed (65 MPH) will give me about 2000 RPM. Thanks....