Chevy and GMC Duramax Diesel Forum banner

LML DPF Regerations

100K views 359 replies 58 participants last post by  Hotshot lml 
#1 ·
I have taken my truck to the dealer when the truck was going through regenerations every 450, 350, & 250 miles. Sometimes the truck was brought into the bay to have the mechanic delete the DTC codes. Regular oil changes are done every 5000 miles. Stock intake was originally getting about 18-20MPG. I replaced the stock cold air intake when the regenerations were taking place every 200 miles. I replaced it with a Air Raid Cold air intake system to help improve MPG, which initially it did. I was and occasionally see 24MPG while traveling between 50-62MPH while not going through a regeneration cycle.

I have incorporated an Edge CTS Insight (monitor only) to get data back from my vehicles performance. The soot mass triggers the regeneration cycle when it hits about 40-43grams of soot. Regeneration cycles are now taking place every 70 miles and has just started again after 55 miles. Soot mass is building up quicker. I do not agree with the next thought that is it because of the cold air intake. I was already seeing regeneration frequency problems prior to the installation of the unit. If I were to guess, the DPF filter is not sufficiently burning off the particles and the DPF Filter unit is becoming plugged. EGT1 sensor location (post turbo) reaches is between 650 and 750 degrees under normal driving conditions in regen cycle. EGT#2 sensor location (pre SCR) currently reaches between 1000 - 1400F under normal driving conditions in regen cycle. Post DPF sensor is burned out and stuck on 1832F all the heat through the system pretty much fried the sensor is my thought.

The common response I have received so far from the dealer mechanic is that the truck is fine. There is nothing wrong and they system is functioning as it should. If everything is fine, I should not be reading on the monitor that a fault DTC code #2459 stating the regeneration cycle frequency is too often. I also have a fault DTC code 1010 problem from the Mass Air Flow Sensor.

What else could it be?:cookoo[1]:
I am thinking that the MAFS is bad or the DPF filter is plugged or both.
 
See less See more
#2 ·
There are many factors that regulate regen
1. Fuel quality
2 . driving
3. Outside air quality aka the smokey air
4. Temperatures
Just my experience

Sent from AutoGuide.com Free App
 
#3 ·
I thought I bought a truck that is supposed to run great with no issues. I think some people call it temperamental.

liable to unreasonable changes of mood, emotional, erratic, unpredictable, changeable, inconsistent.

That is a great description of my wife!!! Now I have a truck to match?!?!?! I am screwed.
 
#5 ·
Well I called the dealer of whom I purchased the vehicle from. I went right to the service mgr., who emailed the brand mgr., and then someone else who came to the conclusion today, "You need to put the original stock intake on the vehicle and bring it back to the dealer for us to run further test and check the vehicle."

My response to him was that GM built an engine that a consumer cannot install aftermarket products on that work with the vehicle??? GM response, "yes, the truck was built to our stock products not to after market products and we cannot test the vehicle with every after market product."

I have seen components first hand pulled from a deleted vehicle. My first worry is that I have fried everything and I am a little worried about long term damage. Even after I pull the crap off after 41000 miles.

I did not know that there was a club. I thought I was a special case. That is what my wife says.
 
#6 ·
Delete & your DPF troubles are gone. Or you can, hope for a dealer to figure out whats wrong, & fix it. Dont hold your breath, for a dealer fix. "No CEL no problem" Is the motto.
 
#9 ·
Ok. Soot was at 35 grams and the vehicle regen'd again. Funny thing, well I am not laughing, but the soot level went down to 2 grams, the temperature started going down from a high of 1417F at the EGT#2 location. The high temperature dropped down to normal running temps at EGT2 position. While running between 50-55mph the soot mass went from 2 to 9 grams within 2 miles, right after a burn. Stopped at a light and the RPM's were stilling running at 800. Drove for another 3/4 of a mile to home and shut the car off still at 800rpms.

Just documenting the nightmare so everyone else can see what a F****** mess this is. Should be able to look into my engines exhaust system with in the next 3 weeks or so.
 
#11 ·
On my stock lmm with a bad dpf, visable black smoke I still regen every 450-500 miles
 
#13 ·
Black smoke?



I can step on it during a burn cycle and the smoke is white. I might feel different about my truck if the regenerations were happening every 450-500 miles. I would keep everything stock, but, that is obviously not the case with the truck I am driving. I only wish I knew when the last EGT #4 sensor went bad. It probably happened right after I drove it off the lot.
 
#12 ·
I would like more people to post here if they have a problem. It seems as though GM is clueless that this actually happens on their products. I mean some besides me must have complained to GM about how poorly this system performs. Another recall? Lawsuit?
 
#14 ·
Sometimes I find soot meter not reading correctly. Lately I have been able to allow the truck to run through an entire cycle of regen on some lengthy drives, I had one cycle last 40 minutes. The upside is that it had a chance to clean itself out completely. Now my soot meter drops to 0, for a few months prior to that it was stopping the regen cycle when it hit 9 or 10.

Sent from AutoGuide.com Free App
 
#15 · (Edited)
You bet there is a sub 200mi regen club. See my sig... Also many other threads on this topic.

Instead of fighting the dealer, I would just go ahead and put the stock intake back on. At the end of the day I don't think its going to help you though. GM's canned response is if the truck is not throwing codes will be "working as designed".

Been there, done that... Several times now.
 
#19 ·
X2 on putting the stock intake back on and let the brain trust from GM figure it out. Don't give them a reason to deny any warranty work due to an aftermarket intake. You have already alerted the the next level up and they are willing to help remedy the problem, don't get pissy until they won't work on it under warranty.
 
#18 ·
#21 ·
Might be worth checking but when i was stopped at high idle during regen there was clearly a lot of heat being generated from the exhaust. might be worth hoping out with the truck parked and seeing if its getting hot enough to burn it out.

X3 on taking it to the dealer.
 
#23 ·
meaning



What is x3 and x2? Sorry if this is a dumb question from a newbie
 
#30 ·
Differential Pressure sensor




Well, truck has been in the shop since Monday. Early report is that a Differential Pressure Sensor was bad and parts are being ordered. Truck should be ready today or tomorrow.

I just wonder how long the new sensor will last. How many times have people had theirs replaced. How does this sensor measure and tell the engine that it needs to burn?
 
#26 ·
The air/fuel ratio needs to be spot on for the emission system to work as designed. It also needs to have precise control over the exhaust temperature to allow the SCR and DPF to work correctly. That's why you see four temperature sensors on the exhaust.

The mass airflow sensor is very important to prevent overloading and cleaning of the DPF. I wouldn't even attempt troubleshooting this until you had the sensors all reading valid data and the stock intake installed. I would suggest either leaving it bone stock or deleting it completely.
 
#28 ·
This is why I have an Edge Insight to monitor my temps. If I am in a regen cycle and I need to kill the engine, I let it cool off with engine running at idle for 5 minutes. Around here right now it is no where near any dry brush or grass, it will start a fire.
 
#29 ·
Round up

10 day trip. 750 + a few pulling the trailer.
14 regenerations while during the 10 days. Average 8-9 MPG while pulling during regeneration, 10-12 MPG otherwise while pulling. Engine light came on only to stay on after about 250 miles of the trip. Still on and heading to a dealer later today. So I averaged between 50-60 MPG between regeneration cycles. I have all the information gathered so from the threads and I greatly appreciates everyone's input and comments to help fix the problem for GM.

EGT 1 post turbo up to 1200F
EGT 2 pre SCR up to 1400F

I would not necessarily say that I had a loss of power during the trip. There were some big hills on the trip.
 
#31 ·
Very few diff pressure sensors reported replaced.

I wonder if more are 'bad', but not completely 'failed', resulting in frequent regens.

Soot level is calculated from the pressure differential (pressure drop) across the dpf)
 
#32 ·
Delete that baby and never look back. From my experience with my 14, dealerships do not like to do shit with their warrenty so I said screw them and deleted mine. What a dream come true and it's a completely different truck
 
#143 ·
What problems did you have with your 14?
 
#33 ·
I took mine to the dealership a few weeks ago when I noticed the regen cycles dropped from 280 miles to 180 miles. The replaced the DPF pressure sensor. The tech also noted that the last 2 regen cycles had not finished. Which I believe since the regens would quit at 8 grams instead of 0 grams prior to the shorten cycle. Its slowly trending back to 180 miles. I've noticed that the soot grams are building faster that immediately after the repair. I tend to the think these issues are combination of correctly reading the soot grams / pressure, DPF failing to complete a regen as intended, and possible the truck producing more soot than intended. Just some thoughts to add to the discussion.
 
#34 ·
Took the truck to a another dealer. I did not take the truck to the dealer I purchased the vehicle from. GM Brand management want me to implement the stock air intake. I got a hold of a dealer that would look at the truck with after market products, NO QUESTIONS ASKED. P0101 coded had been thrown because the air filter was plugged. I ordered a new one today. The mechanics found a bad differential pressure sensor. I left the lot on Friday did a little running around. Pulled a 4-5000lb trailer to the hunting property. 300 miles 5 regenerations. 60 miles average then burn. I agree with deleting and all the problems go away. The problem is I paid off a 63K truck and I have all kinds of issues and I know that it is nothing that I done to the truck.
 
#35 · (Edited)
How many miles are left on your warranty? I would plug both sides the pressure sensor into the leading pressure port, which will cancel all regens.... then drive it until the DPF plugs solid, then put everything back and go get a new DPF installed.

Do this continuously , and at several hundred dollars a pop, GM will get more involved.

EVERY Duramax owner with regen issues should do this.... the problem will then get the attention it needs....




This is the sensor I'm talking about.... its up on the Pass side frame rail.
 
#36 ·
Well, I roughly have about 42,500. 5yr, 100000 miles. The truck has been back to the same dealer for constant regens over the last 2 years. Only until recently have I decided to look at other dealers for a solution. The major problem is that GM has an issue. What is it doing to the truck? If they don't have a clue what is going on with the system, what is happening internally to the engine beside collecting soot. What happens when the engine goes to crap after 100,001 miles and my warranty is gone?
 
#38 ·
DPF crap is covered up to 50k then you own it. I think GM knows the system is crap.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top