High idle and possible sticking exhaust brake.

[KMyrick]

I am experiencing issues with what seems to be the exhaust brake engaging while in park. The engine will go to a high idle and the engine gets a muffled sound to it. When this happens, you can start from a dead stop and accelerate but the truck will not go as it should. It feels like the exhaust brake is kicking in are holding the truck back while trying to go. Temperatures were in the high 70s to low 80s. Any ideas?

Thank,

Kyle

 

[gsbrockman]

I can say with 99.9% certainty that your truck is in the process of performing a regen.

 

[KMyrick]

How long does a regen take? This occurred several times over a 3 day period.

 

[Newsa]

It does idle a bit noisier when doing active regen.

What has your driving been like the past few days? Hwy? City?

If it didn't complete the regen, it will continue to act like that.

If you took only short trips, wouldn't worry about it.

 

[KMyrick]

When this issue occurred, the truck was used to pull a stock trailer for about 200 miles over flat/hilly terrain. There was city driving after that. Since returning, it has not done it since. This brings up another question. Why would the regen process cause a loss/delay in power during driving? Seems like a safety issue to me.

 

[Newsa]

When this issue occurred, the truck was used to pull a stock trailer for about 200 miles over flat/hilly terrain. There was city driving after that. Since returning, it has not done it since. This brings up another question. Why would the regen process cause a loss/delay in power during driving? Seems like a safety issue to me.

From an article about DPF regens a few years old:

Active regeneration is accomplished by changing parameters in the engine to increase the exhaust temperatures in the DPF. This requires precise knowledge of engine parameters and access to the engine control unit. Because of this, the engine management approach is performed by the OEMs that have direct access and control over their engine design.
Among the active strategies used are: late or post-injection of fuel into the combustion chamber, changes to the turbo boost, changes to the EGR valve, intake air throttling, and retarding the injection timing. All these methods can raise the exhaust temperature, but they also have negative impacts on the vehicle’s fuel economy, power, and engine wear.Post-injection (late-cycle injection) in particular causes increased engine wear by diluting the engine oil film with fuel. Some of the other methods also decrease available oxygen in the exhaust, which impacts the soot-oxidizing ability of the particulate filter. Lastly, much of the heat generated by increasing the combustion chamber temperature is lost to engine coolant and engine components, thus decreasing fuel economy.Read more:*http://www.trucktrend.com/how-to/engine/1107dp-dpf-the-time-bomb-under-your-diesel/#ixzz3fydjobvK

 

[KMyrick]

Thank you Newsa. Great article. I always enjoy learning something new about these trucks.

 

[gsbrockman]

Thank you Newsa. Great article. I always enjoy learning something new about these trucks.

Thankfully.....the 2013 & newer pickups don't use any post injection events for regeneration, like the 2007.5 through 2012 pickups.

 

[Newsa]

Oo.Yeah, TDR forum is a great place to learn and share. These fellas get a little too excited about their B&W hitches though. Oo.

 

[Newsa]

Thankfully.....the 2013 & newer pickups don't use any post injection events for regeneration, like the 2007.5 through 2012 pickups.

Didn't know that. Thanks Brockman!

 

[kthaxton]

Thankfully.....the 2013 & newer pickups don't use any post injection events for regeneration, like the 2007.5 through 2012 pickups.

How do they regen then? Is it simply enriching the initial normal combustion cycle?

 

[gsbrockman]

To my knowledge.....with DEF and Selective Catalytic Reduction, there's no longer a need for multiple post injection events. I imagine that's why the 2013 DEF equipped pickups now have 15k OCI's. The 2007.5 through 2012 trucks had a maximum OCI of 7.5k. The 2003 through 2007 HPCR's also had up to a 15k OCI.

 

[Newsa]

I would think post injection would increase the OCI, not enriching the fuel mixture.