Technical DPF regeneration failed.

[Golonko]

I'm at a loss overall but some things/clarifications come to mind.

Did the new DPF have at least a couple of smoke free regens after it was installed, or was it also smoky from the start?

This thing about the dashboard resetting -- is there more than the messages you'd get if you manually disabled the cruise control?

Is your oil level going down?

Is the reconditioned engine the same type as the one before?

What I can offer is if you record a regen attempt with the speed, rpm, instant fuel consumption, differential pressure, DPF temperature I can try to match that next time mine is due and we can compare the data. Ideally with some normal driving before.

Looking at your graphs again, your DPF is quite blocked and the soot load should be way above 100%. Do you have a longer recording?eplace

In the first regeneration with new DPF there was a very low smoke. In the followings more smoke but not so before replacing.
Yes, the oil level is going down. Now i have to replace the PCV valve, because is passing oil to the intake (second time replaced with the new engine).
I can't export my recordings. I use Ediag app.
I had the same regeneration problema before replacing the engine. Replacing the inyectors became crazy, triggering to have to get a new engine.

 

[lycopersicum]

There's a document from FIAT listing possible causes of DPF malfunction:

1 - Incorrect thermostat operation
2 - Incorrect flow meter reading
3 - Incorrect injection operation
4 - Presence of oil in intake circuit
5 - Turbo compressor problems
6 - EGR valve problems
7 - Condensation
8 - Oil leakage from valve guides

On 3 (injectors) it says:
high particulate production-regeneration cannot be run.
- check correspondence between IMA injector codes and injector codes written in ECU.
- try to reset self-learnt injection amount.
- replace the injectors.

4 seems relevant given you have an issue with oil in the intake.

On 6, EGR valve --
The EGR valve problems are the most difficult to diagnose.
Faults of this component will cause high smokiness and as in the other cases, incoherent CCM data and consequent lighting of the engine warning light (MIL) and the generation of fault code P1206.
In the most severe cases, the ECU has an internal diagnostic procedure with the generation of a specific error code.
The faults of this component are not easy to diagnose in the least severe cases. Replacement is therefore recommended.

 

[lycopersicum]

This would be my current theory:
- the smoke and high temperature are "normal" when trying to regen a DPF with heavy soot load.
- the dashboard glitch is "normal" when a regen attempt gets interrupted.
- the regen gets interrupted when the pressure goes too high during the regen. This is why driving gently sometimes works.
- regen attempts at 85% soot load indicate that the ECU is confused about the state of the DPF. The ECU thinks the soot load is low but the pressure sensor says it is high. The regens keep happening too late.

Why the mismatch?

- either because the mechanic failed to reset the soot load with the new DPF, but this should have "self-corrected" after the first regen

- or because the exhaust contains abnormally high soot, so the DPF is filling up faster than normal

- the root cause for the high soot production could be any of the 8 things listed in the previous post.

 

[Golonko]

There's a document from FIAT listing possible causes of DPF malfunction:

1 - Incorrect thermostat operation
2 - Incorrect flow meter reading
3 - Incorrect injection operation
4 - Presence of oil in intake circuit
5 - Turbo compressor problems
6 - EGR valve problems
7 - Condensation
8 - Oil leakage from valve guides

On 3 (injectors) it says:
high particulate production-regeneration cannot be run.
- check correspondence between IMA injector codes and injector codes written in ECU.
- try to reset self-learnt injection amount.
- replace the injectors.

4 seems relevant given you have an issue with oil in the intake.

On 6, EGR valve --
The EGR valve problems are the most difficult to diagnose.
Faults of this component will cause high smokiness and as in the other cases, incoherent CCM data and consequent lighting of the engine warning light (MIL) and the generation of fault code P1206.
In the most severe cases, the ECU has an internal diagnostic procedure with the generation of a specific error code.
The faults of this component are not easy to diagnose in the least severe cases. Replacement is therefore recommended.

I'm trying for a new garage. Because mine is not interested in waste enough time to find the problem... I'm looking for a Fiat official garage but they don't want campers. They do not accept campers directly or when I say it's a camper, they give for three months.
In the meantime i'm going to try by myself something regarding the problem of oil in the intake. I'm going to unplugg the tube from PCV valve avoiding to enter oil from the engine to the intake. So it's going to have always clean air and maybe get a better regeneration. Just for try.

 

[Golonko]

There's a document from FIAT listing possible causes of DPF malfunction:

1 - Incorrect thermostat operation
2 - Incorrect flow meter reading
3 - Incorrect injection operation
4 - Presence of oil in intake circuit
5 - Turbo compressor problems
6 - EGR valve problems
7 - Condensation
8 - Oil leakage from valve guides

On 3 (injectors) it says:
high particulate production-regeneration cannot be run.
- check correspondence between IMA injector codes and injector codes written in ECU.
- try to reset self-learnt injection amount.
- replace the injectors.

4 seems relevant given you have an issue with oil in the intake.

On 6, EGR valve --
The EGR valve problems are the most difficult to diagnose.
Faults of this component will cause high smokiness and as in the other cases, incoherent CCM data and consequent lighting of the engine warning light (MIL) and the generation of fault code P1206.
In the most severe cases, the ECU has an internal diagnostic procedure with the generation of a specific error code.
The faults of this component are not easy to diagnose in the least severe cases. Replacement is therefore recommended.

There's a document from FIAT listing possible causes of DPF malfunction:

1 - Incorrect thermostat operation
2 - Incorrect flow meter reading
3 - Incorrect injection operation
4 - Presence of oil in intake circuit
5 - Turbo compressor problems
6 - EGR valve problems
7 - Condensation
8 - Oil leakage from valve guides

On 3 (injectors) it says:
high particulate production-regeneration cannot be run.
- check correspondence between IMA injector codes and injector codes written in ECU.
- try to reset self-learnt injection amount.
- replace the injectors.

4 seems relevant given you have an issue with oil in the intake.

On 6, EGR valve --
The EGR valve problems are the most difficult to diagnose.
Faults of this component will cause high smokiness and as in the other cases, incoherent CCM data and consequent lighting of the engine warning light (MIL) and the generation of fault code P1206.
In the most severe cases, the ECU has an internal diagnostic procedure with the generation of a specific error code.
The faults of this component are not easy to diagnose in the least severe cases. Replacement is therefore recommended.

Hi,

lycopersicum, can you share that document?​

Thanks in advance.

 

[lycopersicum]

Hi,

lycopersicum, can you share that document?​

Thanks in advance.

Sure here it is. It's from 2009 and not fully accurate (the actual euro 5 system ended up being a mix of what it describes as euro 4 and euro 5) but quite detailed.

 

[Golonko]

HI,
I’m still facing the same issue. I’ve cleaned the EGR valve, replaced the throttle body, and also replaced the PCV valve, so there should no longer be oil entering the intake.
However, the problem persists. During regeneration there’s a lot of white smoke, and sometimes it feels like a momentary power cut, as if the ignition was turned off.
Yesterday, during a regeneration cycle, the temperature at the DPF inlet reached 893 °C, then the process stopped suddenly and the ECU stored code P2085-11 (exhaust gas temperature sensor fault).
So, even with the new DPF, new sensors, and a clean intake system, regenerations are still interrupted due to excessive temperature and heavy white smoke.
On top of that, I’m now getting bursts of black smoke when shifting gears, even when the DPF isn’t regenerating. Overall, there’s more continuous smoke than before.

 

[lycopersicum]

The black smoke indicates unburned/partially burned fuel.

It also means that unfortunately your DPF must have cracked from the excessive heat and is letting the soot through.

On the plus side, all of this would seem to narrow down the issue to an overfueling issue. The engine is running too rich. This causes the high temperature and the excess soot / frequent regens.

I think the exhaust system is not to blame and the issue is with the fuel injection or air intake system.

Others will be more competent than me to take it from there...

You could try to find a good diesel injection specialist and tell them to ignore the DPF problems for now and investigate a potential overfueling problem.

 

[theoneandonly]

HI,
I’m still facing the same issue. I’ve cleaned the EGR valve, replaced the throttle body, and also replaced the PCV valve, so there should no longer be oil entering the intake.
However, the problem persists. During regeneration there’s a lot of white smoke, and sometimes it feels like a momentary power cut, as if the ignition was turned off.
Yesterday, during a regeneration cycle, the temperature at the DPF inlet reached 893 °C, then the process stopped suddenly and the ECU stored code P2085-11 (exhaust gas temperature sensor fault).
So, even with the new DPF, new sensors, and a clean intake system, regenerations are still interrupted due to excessive temperature and heavy white smoke.
On top of that, I’m now getting bursts of black smoke when shifting gears, even when the DPF isn’t regenerating. Overall, there’s more continuous smoke than before.

Have you got any data of a regen with percentage clogging. Have you a graph of the inlet reaching 893C.
I can only agree with @lycopersicum
On the plus side, all of this would seem to narrow down the issue to an overfueling issue. The engine is running too rich. This causes the high temperature and the excess soot / frequent regens.I think the exhaust system is not to blame and the issue is with the fuel injection or air intake system.

The one thing that has not been confirmed (or I couldnt find it) is the coding of the injectors are they correct in the physical location. I once seen a van with 2 new injectors and 2 in wrong position that clogged the DPF too quickly and high differential dpf pressures, a recoding and physical DPF clean resolved that isssue.
Have you done a leak off test?

 

[lycopersicum]

Here, someone mentions overfueling caused by corroded pins on the ECU. One more thing to check...

 

[Golonko]

Have you got any data of a regen with percentage clogging. Have you a graph of the inlet reaching 893C.
I can only agree with @lycopersicum
On the plus side, all of this would seem to narrow down the issue to an overfueling issue. The engine is running too rich. This causes the high temperature and the excess soot / frequent regens.I think the exhaust system is not to blame and the issue is with the fuel injection or air intake system.

The one thing that has not been confirmed (or I couldnt find it) is the coding of the injectors are they correct in the physical location. I once seen a van with 2 new injectors and 2 in wrong position that clogged the DPF too quickly and high differential dpf pressures, a recoding and physical DPF clean resolved that isssue.
Have you done a leak off test?

Here you have the graphical when the temperature get 893C. And then when it fall to 200C when the error appear and the regeneration is stopped.
How can I do the leak off test?
I’m working with a new mechanic now, and he can’t check the injector coding because they’re refurbished, not new, and don’t have the codes printed on them. I guess my previous mechanic had those codes when he bought them. Anyway, the injection correction values seem to be within the acceptable range of ±2.

 

[lycopersicum]

Here you have the graphical when the temperature get 893C. And then when it fall to 200C when the error appear and the regeneration is stopped.
How can I do the leak off test?
I’m working with a new mechanic now, and he can’t check the injector coding because they’re refurbished, not new, and don’t have the codes printed on them. I guess my previous mechanic had those codes when he bought them. Anyway, the injection correction values seem to be within the acceptable range of ±2.

It looks like the temperature sensor may have actually burned out during this event.

 

[Golonko]

It looks like the temperature sensor may have actually burned out during this event.

When I stopped the engine and started it again, the sensor began reading correctly. But I’m afraid it might have been damaged. I replaced it last August.
It’s crazy to replace it only for it to burn out again on the next regeneration.

 

[Golonko]

Update after several months – injector-related issue

Hi all,
I wanted to update this thread after a long diagnostic process and several thousand kilometers.
After October I changed mechanic and continued the investigation step by step. During this time, the following work was done:

• EGR removed and cleaned
• Intake and exhaust system checked and partially dismantled
• DPF confirmed as new and not physically blocked
• Turbo, sensors and ECU software had already been checked previously

At some point, the engine also started producing bursts of black smoke during acceleration, which initially led us to suspect that the EGR might not be operating correctly. This was one of the reasons why the EGR was removed and cleaned.

Despite all this, the engine was still producing heavy white smoke during regenerations, very high exhaust temperatures and, at times, aborted regenerations.

The key finding eventually turned out to be related to the injectors.

Although the injectors had been replaced in the past, they were remanufactured units, not new. I was also told by my previous mechanic that the injectors had been sent for checking twice. However, it later became clear that a proper leak-off / return flow test had never been performed on the vehicle.

Once this test was carried out, it showed that two injectors had abnormal return values, indicating that they were not working correctly.

While checking part numbers, we also noticed that one injector was of a different reference compared to the others. We cannot say with absolute certainty that this injector was incompatible with the engine, but it raised doubts about injector matching and calibration consistency.

What was clear is that the injectors were not behaving uniformly, which can strongly affect combustion and post-injection during DPF regeneration.

I decided to replace all four injectors with brand new Bosch units of the same reference.
After this:

• Black smoke disappeared completely
• Regenerations are now completing correctly
• White smoke during regeneration is still present but significantly reduced
• Over ~3000 km and 3 regenerations, no aborted regenerations so far

So in my case, the root cause was related to injector condition and balance, even though they had already been “replaced” before.
The return flow test and replacing all injectors as a matched set made a clear difference.

Final note: I haven’t re-checked exhaust temperatures during regenerations, mainly because my current mechanic has strictly forbidden me from connecting any diagnostic tools anymore — apparently for the sake of my mental health

I hope this update helps others facing similar DPF regeneration issues.

 

[niceup]

Thanks for updating. That is sooo helpful.
What was the total cost of 4 new injectors + work?
I am thinking of doing injector leak tests too

 

[Golonko]

Thanks for updating. That is sooo helpful.
What was the total cost of 4 new injectors + work?
I am thinking of doing injector leak tests too

300 € each inyector + IVA.

The total invoice was 3000 €. With a lot of hours of work, because very hard to access to EGR

 

[lycopersicum]

Thanks for coming back with an update and glad this ended with a success!

I hope you can now stop worrying and enjoy the regens

 

[niceup]

300 € each inyector + IVA.

The total invoice was 3000 €. With a lot of hours of work, because very hard to access to EGR

Thanks, that's alot.
What about the "reset" of the instrument cluster? Is this also fixed? Which would mean it was a consequential error/knock on effect.

 

[Golonko]

Thanks, that's alot.
What about the "reset" of the instrument cluster? Is this also fixed? Which would mean it was a consequential error/knock on effect.

Good question.


Yes, the instrument cluster resets have also stopped since replacing the injectors.
I haven’t seen any further resets during regenerations or normal driving.


So in my case, it does look like the cluster reset was a consequential / knock-on effect, most likely related to the regeneration being aborted and the engine operating in abnormal conditions (unstable combustion, excessive post-injection, very high exhaust temperatures).


I can’t prove a direct causal link at ECU level, but the behaviour disappeared together with the regeneration issues, so they were clearly connected.