2007 Contessa with 2006 Cat C-9 has DPF muffler ???

[Mark Lorentz]

Hi guys
Yesterday I replaced the 90 degree chrome tail pipe coming out of the muffler and happened to look into the muffler and to my surprise I saw honeycomb
ceramic DPF matrix ?
Being a 2006 engine with no emissions controls I wonder if the wrong muffler got installed.
the muffler looks factory installed and I have 94k on the rig.
I don't believe the 2006 has any way to do a regen so I wonder if it could be plugged or causing to much back pressure
also when pulling away from a stop there is a fair amount of black smoke for about 2 seconds so it is certainly not catching that soot.
Anyone heard of this ?

Thanks

[Eric Maclean]

Mark
What you are looking at is an earlier emissions exhaust treatment system it is not a DPF ( diesel particulate filter)
Which traps the soot and requires a full high temperature regeneration.
Instead it is the earlier system which used a catalyst to convert some of the emissions much like the ones used on cars
They can plug up but usually as a result of an engine fault is bad injector or something vthat causes excessive heat and a meltdown of the honeycomb they can also be damaged by impact breaking the honeycomb.
For the most part they are much more reliable than a DPF system and should last the life of the coach.
Dave Atherton may have more information on your system as to what years they were used and their expected life span etc.

Hope this helps
Eric

[Mark Lorentz]

Thanks Eric
That's interesting, I have never heard of that before
With no sensors on the muffler side of the system you have no way to know if its plugged or working
As I said I have a fair amount of black smoke when pulling away from a stop
The outlet side that I could see looked clean and tan colored.

Thanks again
-Mark

[Eric Maclean]

Mark
Black smoke is a sign of over fueling which only means that there is more fuel being injected than there is air or oxygen to burn it
There are a couple of things to look at before going into injection diagnoses .the first is your air filter check it for dirt buildup if its restricted air flow to the rest of the system can't be supplied because diesels are a full displacement engine meaning there is no throttle plate to restrict air flow they move much more air than a gasoline engine a d are much more dependant on proper air volume .any restriction on the intake side is a bad thing.

Note :  side radiator coaches tend to kick up a lot of dust off the road on gravel campground roads which is easily ingested into the air filter there fore the filter should be check and or replaced annually at the very least.
Second the turbo charger is the main supplier of air for the combustion process if you have a leak at the intercooler or any of the charge air hoses the boost will suffer and result in black smoke under load / acceleration.

Keep in mind that from a standing stop the turbo takes time to come up to speed or spool up during this time it is normal to get some black smoke as the boost pressure has not yet started to provide enough air to keep the combustion mixture from going too rich ( too much fuel not enough air ) as the turbo spools up the the boost pressure increases forcing more air into the engine the black smoke should stop.
at a given point the boost is limited by a boost pressure control device in most cases a waste gate .
When the boost pressure increases the computer using an intake pressure sensor and intake air temperature sensor to determine how much more fuel to add then adds more fuel depending on throttle position RPM and load .
This is why as you pull away from a stop the engine feels lazy untill the rpm start to build and subsequently builds boost pressure at which point you can feel the engine start to pull harder.

Most often a change in the amount of Black smoke produced is a result of a charge air leak as stated above.

Sorry for the long winded explanation
Hope this helps
Eric

[Mark Lorentz]

It does help Eric,
and I like long winded explanations
the air filter is new ....   I will check the charge air system for leaks
Thanks
-Mark

[Eric Maclean]

Mark
Pay extra attention to the aluminum welded joints on the charge air cooler they tend to fatigue and crack.
And of course check all the pipes and hoses for holes or cracks.

Eric