Exhaust Aftertreatment Issues

**Texas149** · 30th August, 2010, 06:52 PM

After lookin around I haven't seen a thread on Aftertreatment problems. In my area I'm seein more and more new trucks goin down with these systems in place. A lot of which are still under OEM warranty however it does little good when your shut down for a week waitin for them to even look at it. These Dpf filters are extremely sensitive and for those who are at the mercy of the new emission standards, maybe we can come together and make life a bit easier. If you have or had some issues please share! I myself and hopefully some others may be able to shed some light on a resolution

**radu_gostian** · 30th August, 2010, 07:11 PM

Usually DPF are going bad when u use a car improperly. They don't like short run's with cold engine. They work best for long distances at constant rpm's (2500). There are 2 types of DPF, ones who need replacement and ones who regenerate themself. With the first one you'r out off luck usually they need to be replaced but with the second ones a 40 min drive at 2,500 - 3,000 rpm's in the third will quire it.

**Texas149** · 30th August, 2010, 09:22 PM

Thanks for the post!

I know the applications in which these set-ups are used vary greatly. The main direction I was hoping this thread would take is for the heavy duty applications. Heavy trucks, Power generation, etc. In the on-highway trucks the cure isn't so simple as to cruise it @ high rpm. Engine loads and speeds and other variables play a big role. We can see this is more evident as these systems are being refined over and over!

**rp1210a** · 30th August, 2010, 11:29 PM

Manual/Forced Regen is the key before problems arise

**Texas149** · 31st August, 2010, 06:11 PM

Is it that you mean forced regens are the means to prevent problems from arising or that they can cause problems with these systems?

**Floyd** · 31st August, 2010, 06:29 PM

Forced regeneration is carried out normally using diagnostic equipment. If your talking truck applications and your having lots of trouble with this system, then it sound like you need to speak to the manufacturer to see if there is a software update for the engine ECU/DPF system!

**rp1210a** · 31st August, 2010, 06:48 PM

Forced/Manual regens are the way to prevent some of the problems. Depending on driving habits the conditions for running the regen during normal drive may never be correct so it just wont run or not run long enough. Some trucks let you run a manual keygen using a button on the dash. Sometimes if the DPF is too far clogged the manual regun button wont work and you will need to force it via the oem soft.

**Texas149** · 31st August, 2010, 09:55 PM

Originally Posted by rp1210a

Forced/Manual regens are the way to prevent some of the problems. Depending on driving habits the conditions for running the regen during normal drive may never be correct so it just wont run or not run long enough. Some trucks let you run a manual keygen using a button on the dash. Sometimes if the DPF is too far clogged the manual regun button wont work and you will need to force it via the oem soft.

Right on M8! Lighter duty loads and short in city hauls won't let the DOC reach optimal temps for a sufficient duration to acheive a successful burn...Depending on the zone conditions of the DPF, some trucks will only allow a parked regen if a certain zone (zone as in filter buildup state) is acheived. I have seen bad injectors overfuel and crack the DOC and leave the truck crippled once the DPF zone reaches severe levels. I think I seen an outfit who manufactures "aftermarket" DPF's which incorporate a different design than current filters employ. Instead of the "wall" flow, it is a pass thru design. Less restrictive and still meets oem/epa standards. A bit pricey 2RC but I'll try to find 'em again.

**RSwire** · 31st August, 2010, 11:36 PM

Thanks Texas149 for starting this thread. The company I work for is starting to get more of these vehicles in so any info i can aquire about them is wonderful. What ever happened to the good old days of streight pipes bellowing smoke and jake-brakes rattling windows.

**Texas149** · 2nd September, 2010, 07:49 PM

Your welcome bud. The same thing is happening to me. Trucks can't just sit and wait till the dealers have time to get to 'em. I'm the epitome of "On the job training"! Its really shifting gears in the industry. Now more turning some screws to roll the black smoke. R.I.P. to all those Small/Big Cams and B models. Say hello to the the New School. Keep up or get left. NOT ME I TELL YA!!!! Wish someone would bring me an old 16v149 2cycle detroit to rebuild. Those were the days my friend.

Back on topic....had a MBE 4000 come in. Propane truck. Active burns are disabled so manuals are the only way for this application. Ran through diagnostics; no codes. Will initiate regen and run indefinately. Noticed no response from Fuel Doser and Intake throttle valve during burn. Bingo! Ran doser routine and checked to be functional. Ran Intake throttle valve routine and showed to be functional. Hmmm. What the heck? Turned ignition off and couldn't hear the Intake valve "sweep" closed. So....I then removed the top cover off of the module on the valve assembly. There it was! Plastic junk! One of the teeth on the plastic gear broke off and lodged in the mesh of the mating gear and locked it up in the full open position. Oh yeah that part is on national backorder.

**dafdiagnos** · 2nd September, 2010, 08:47 PM

i take it that you are on about the 'wonderful' world of scr - selective catalytic reduction using adblue, with the stainless/ titanium injectors etc. nothing but trouble

**rudamie** · 3rd September, 2010, 08:04 AM

Sweet thread.....! Gents also remember ultra low sulfer diesel is a must. Becareful that you don't pick up bad fuel. Make sure the pumps has a sticker that says Ultra Low Sulfer. If your not sure dont fill up there. Small towns my have old fuel. The Particulet Trap (P-Traps) will plug with particulet matter with a quickness. If you feels the truck slugish. Hook up a merc monometer to an exhaust port in front of the P-Trap area, and check how many inches of back pressure is present? Make sure the engine back pressure is with in specs. I would keep a spare P-Trap on hand, drain the fuel.

Woot Woot.....! Share On Gents

**renesis** · 7th September, 2010, 03:37 PM

Originally Posted by dafdiagnos

i take it that you are on about the 'wonderful' world of scr - selective catalytic reduction using adblue, with the stainless/ titanium injectors etc. nothing but trouble

Yes the wonderful SCR system is causing alot of headaches in my area whereby the UREA doser pump will choke. I'm in a tropical country (temperatures around 30C, so no freezing). Cummins service dealers will shift the blame to the OEM for improper installation...etc

Replacing the UREA doser pump is the only solution, and even after that an ECM recalibration is required to restore power back after the derate.

Oh and did I mention the failed exhaust catalysts? That costs a bomb to replace if they are no longer within the warranty period!

**MDR72** · 16th September, 2010, 03:55 AM

live in US and scr is in full swing here can't wait for the cold. lots of problems with doser fuel injector still plugging, and lately lots of nox sensor failures,cunnims replaces and reflashes ecm to repair. still trying to get answer on exactly how much "monkey piss" these are to use. have several locals who have scr one get 3.8 mpg and has used 150 gal "piss" to 20000 miles. lots of factors to consider, but still very costly.

**hercamp** · 16th September, 2010, 05:41 AM

well...just my experience...same of mdr72..the cost of parts ..make the trucks owner doesnt want pay to boy with laptop that try to diagnostic ecm or sensors problems..dealers try to get money from low cost parts and bad dpf sistems ..in the first 2 years runn so nice but after 3 or more years start a lot of problems ...exhaust temp sensors...delta presure...egr positions ...this one so common in isx?s...the low power in 60?series ...and sucks performance of mbe 4000 ...with particulars pld pumps bad responce and low torq in engine and many many ...else..