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The OM651 engine has frequent Diesel Particulate Filter (DPF) regeneration.


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Greetings, gentlemen! I am experiencing significant frustration with my 2014 CLA equipped with the om651 engine. The dpf continues renewing every 60 miles or so.

Thus far, I have replaced the DPF pressure sensor, thermostat, and ECU software, however it has had no discernible impact. The car operates smoothly without any engine knocks, exhaust tips are free from soot, and there are no fault codes detected.

A local independent source informed me that all injectors need replacement. What is your opinion on this matter? As previously said, the automobile does not have any problems whatsoever, including smooth cold starts. How did they get to this conclusion? Xentry was used for the diagnostic, however, the injectors and other components were not examined.

Thank you for all of your responses!

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If there is an imbalance in fuel delivery from certain injectors, it might lead to the formation of particles, which then accumulate in the Diesel Particulate Filter (DPF). I have reservations about the notion that all of them are negative. Typically, when one component fails, others will compensate, potentially causing the xentry values to exceed the acceptable range.

Frequently, the pipes of the DPF sensor might get obstructed, resulting in the occurrence of a failure code or the need for regeneration.

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The ECU is using rpm to measure combustion and is modifying injection time in an attempt to maintain consistent power levels across each cylinder. If the correction values exceed a certain threshold, it indicates a malfunction in the injector. Undoubtedly, any additional mechanical malfunction that impacts combustion efficiency, such as low compression pressure, may result in a similar outcome. Conducting a bench test will provide complete certainty.

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Thank you for providing this information; it is much valued. During idle, the adjustments in my instance deviate by a maximum of 3 rpm, but often stay within 1.5 rpm per cylinder, as shown by the diagnostic tool. Is this acceptable?

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The SDS provides information on the permissible deviation in the smooth run test. However, the injectors own their individual correction values, which provide an indication of the injector's "condition".

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No, regrettably not. The diesel particulate filter (DPF) has been removed and thoroughly cleaned. Additionally, a new DPF pressure sensor, thermostat, and software have been installed. Despite these measures, the DPF continues to undergo regeneration every 60-70 miles.

The automobile operates flawlessly, without any indications of malfunctions, starting difficulties, or other issues. The vehicle was connected to the Xentry diagnostic system on three separate occasions at two distinct locations. However, no defects or signs of any issues were detected. It is really causing me to become mentally unstable.

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The pace at which the diesel particulate filter (DPF) becomes filled grows rapidly. However, even when the DPF is 20% or 80% full, the pressure at idling remains consistently at 5-6 millibars. This is very perplexing.

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It has not been remapped and it lacks ad blue. The reset procedure was performed twice on the dfp, first using xentry which had no effect, and then attempted again using my launch tool, with no success. I have included photographs of my diesel particulate filter (DPF) prior to the cleaning process. Presuming the diesel particulate filter (DPF) is functioning well, it may be inferred that the opposite side was already free of contaminants prior to undergoing chemical cleaning.

image.png.9a5587ee85c971ccc08b23d1436b2b73.pngimage.png.a854778d0fc4f3d011d140a9837b88ce.png

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Here is a photograph taken after covering a distance of around 30 kilometres by driving. At the beginning of the journey, the soot level was 0% because it was immediately after the diesel particulate filter (DPF) was reset and cleaned. I am perplexed as to why the ash content is 2.7g, considering that the system was thoroughly cleaned and all values were reset to 0.00.

image.png.39c3d5f8bd008b954571c49f776cf294.png

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It seems that the system believes it has reached its capacity and initiates a regeneration process. After each combustion, the soot residue is deposited as ash, which gradually accumulates and obstructs the diesel particulate filter (DPF). As far as I know, in order to eliminate the ash, one must dismantle the diesel particulate filter (although I lack expertise in this matter). What method did you use to cleanse the diesel particulate filter (DPF)?

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All parameters, except pressure, are considered 'calculational', hence the ecu assumes it has knowledge of the ash content. The regeneration process of an automobile begins when either the computed value reaches its limit or when the pressure sensor reading hits a certain threshold.

So, if I understand well, you are asking whether the calculation value remains constant despite the pressure differential not increasing? A plausible explanation for the significant smoke and filter contamination in real-life scenarios might be attributed to mechanical issues such as EGR leakage or excessive boost pressure.

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I appreciate your responses. Thus, the enigma becomes more profound. The dpf values have been reset after a chemical solution cleaning. The regeneration intervals prior to the diesel particulate filter (DPF) cleaning were around 70 miles. Following the dpf teach in, I have determined the subsequent regeneration intervals:

The first trip covered a distance of 202 miles, with the whole journey taking place on the highway. The second trip included a distance of 251 miles, with 50% of the journey taking place on the motorway and the other 50% in the city. The trip included many chilly starts and other similar conditions.
The distance is 166 miles and the whole route consists of motorways.

The current measurement for ash is 0.2 grammes. The question pertains to the reason for the significant variation in the lengths covered during regeneration. All the highway journeys were essentially similar in terms of speed, RPM, and refuelling locations.

I am experiencing a state of extreme mental agitation and amusement at this moment. 🤣

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After analysing the available data, I saw that under comparable operating circumstances, the fill rate over a 60-mile distance on the highway climbed by 7% while driving. However, during the latest instance, covering the same 60-mile distance on the motorway resulted in a fill rate of 38%. To me, it represents a significant disparity in the pace at which the diesel particulate filter (DPF) is being filled. Both travels exhibited remarkable similarities, such as the absence of traffic, a consistent speed of 70 miles per hour, the vehicle being completely warmed up, and the use of Shell V-Power diesel fuel.

These are photographs of the temperature sensors under maximum workload as the rate of filling grew rapidly.

image.png.3af3ec2bbaf1d610ec8f6b6a1fe98ea3.png

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Have you verified the proper functionality of the new pressure sensor? I recommend revisiting this matter if you have not done so before.

If you own the appropriate SAN tool, you should be capable of discerning the cause behind the most recent 16 regenerations. May provide clarification.

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My suggestion would be to bring it to Jimmy at O'Rileys Auto's. Possesses a YouTube channel. DPF Guru It may be advisable to make the journey in order to avoid causing damage to the Diesel Particulate Filter (DPF), since repairs may be rather costly.

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