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That's interesting/strange. Have they provided any explanation to why there was soot in the LPEGR circuit and exhaust pipe?
Technical Ducato P0401 P0402 P0236 P0238 and limp mode its 2017 Euro 6, EGR changed, What do I check next
- Thread starter Fredastaire
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Technical Ducato P0401 P0402 P0236 P0238 and limp mode its 2017 Euro 6, EGR changed, What do I check next
Of course I have asked, and the answer was: ”… because it is a diesel, and other Ducatos look the same…”
@athoirs you have reported DPF replacement, how many kilometers have you driven so far and if exaust pipe is still completely clean? Is it possible to change DPF without dropping subframe?
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I see what you meant by “Fiat-not-so-Professional" in previous entries...
@jansla and all interested parties, my immediate conclusion is the new LPEGR cooler has fixed the issue, and probably nothing to do with the turbo. Also, regardless of what the mechanics have said about the DPF, it is broken as it has allowed soot to pass. It is almost unbelievable that they have reported they could not see any issue with the DPF, yet the evidence was clearly right before their eyes.
It is interesting that there is still a difference in the turbo boost - but now it is around 5% and not 11% so a marked improvement. What I see in your graphs is what I have seen recently from operational 130HP engine graphs so far as the boost difference goes - so perhaps that is normal for a good 130HP variant. I also note that the Turbo actuator command dips on the odd occasion as it did before, and when it does the turbo boost matches desired - again, perhaps this is normal for the 130HP engine. What I see now is the LPEGR valve modulating correctly and along with that the MAP temperature is higher, and this is coincident with a lower LPEGR temperature which all indicates that the new cooler is allowing the correct amount of gas flow (higher than before) required.
Below are two graphs. The first is before, and the second is after the fitting of the new LPEGR cooler and turbo. It proved difficult from the available data to find the same operating conditions; however, the best I could find is in these two graphs. In both, the engine is at operating temperature and the important point is the HPEGR is shut. This is important as the HPEGR when open will influence and override the important relative parameter measurements which point to the LPEGR cooler as the root cause of the issue with your engine.
In the first graph (before) the LPEGR valve is near full open all the time, the LPEGR temperature is high (average of 100C) yet the MAP temperature is around 28C.
In the second graph (after) the LPEGR valve is modulating around ½ open, the LPEGR temp slightly lower (average of 92C) yet the MAP temperature is around 35C.
So, in the second graph the LPEGR valve can modulate correctly as there is the correct amount of EGR gas flowing to raise the MAP temperature higher, with lower LPEGR gas temperature. This can only be possible if the LPEGR gas volume is higher. In the first graph, the LPEGR valve is near fully open with even higher supply gas temperature but cannot raise the MAP temperature – pointing to restricted flow and hence lower than designed and expected LPEGR gas flow. Because the desired MAF air flow rate is calculated from the design calculated LPEGR gas volume, the MAF reports the correct expected air flow. The trouble is, the LPEGR gas flow is restricted and results in a combined actual gas flow being low.
You can overlay all the other relevant data (as I have done) to look for any other possible influences, but I could not see any that stood out. I have excluded all other parameters from displaying on these graphs for the sake of clarity.
My conclusion is that the DPF is obviously broken (that is undeniable as there is soot downstream), and this has caused the LPEGR cooler to be gradually filling with soot and restricting the LPEGR gas flow. This results in under-boost due to incomplete total gas volume at the inlet of the turbo, and under high demand conditions will create a large enough boost difference to generate fault codes, resulting in protective limp mode.
The important consideration is that the new LPEGR cooler will eventually have the same issue down the track as the DPF has not been replaced. Not only that, but as you have seen the soot gets into the turbo, and that will flow through the intercooler and interconnecting hoses. According to FIAT’s own Service News 10.023.19 the DPF must be replaced at the same time.
Hope that you now have trouble free motoring, but I would be considering what to do about the DPF and perhaps checking the intercooler for any soot. I wonder how FIAT would react if you presented the facts to them along with a copy of the 10.023.19 Service news? The mechanics have fixed a symptom of the fault, but not the cause. You may have leverage to obtain some form of compensation for the future labour charges to replace the DPF.
One further point that I think is worth mentioning here is that the analysis and fault diagnostic power of MES is very powerful. Also, because of the complexity and interrelated feedback loops involved, it is vital to not focus in on just one parameter in isolation, but to maintain a very wide-angle view across all parameters to help determine a particular fault.
BEFORE: Speed: 80kph, RPM: 2300
AFTER: Speed: 75 - 95kph, RPM: 1600 – 2400
It is interesting that there is still a difference in the turbo boost - but now it is around 5% and not 11% so a marked improvement. What I see in your graphs is what I have seen recently from operational 130HP engine graphs so far as the boost difference goes - so perhaps that is normal for a good 130HP variant. I also note that the Turbo actuator command dips on the odd occasion as it did before, and when it does the turbo boost matches desired - again, perhaps this is normal for the 130HP engine. What I see now is the LPEGR valve modulating correctly and along with that the MAP temperature is higher, and this is coincident with a lower LPEGR temperature which all indicates that the new cooler is allowing the correct amount of gas flow (higher than before) required.
Below are two graphs. The first is before, and the second is after the fitting of the new LPEGR cooler and turbo. It proved difficult from the available data to find the same operating conditions; however, the best I could find is in these two graphs. In both, the engine is at operating temperature and the important point is the HPEGR is shut. This is important as the HPEGR when open will influence and override the important relative parameter measurements which point to the LPEGR cooler as the root cause of the issue with your engine.
In the first graph (before) the LPEGR valve is near full open all the time, the LPEGR temperature is high (average of 100C) yet the MAP temperature is around 28C.
In the second graph (after) the LPEGR valve is modulating around ½ open, the LPEGR temp slightly lower (average of 92C) yet the MAP temperature is around 35C.
So, in the second graph the LPEGR valve can modulate correctly as there is the correct amount of EGR gas flowing to raise the MAP temperature higher, with lower LPEGR gas temperature. This can only be possible if the LPEGR gas volume is higher. In the first graph, the LPEGR valve is near fully open with even higher supply gas temperature but cannot raise the MAP temperature – pointing to restricted flow and hence lower than designed and expected LPEGR gas flow. Because the desired MAF air flow rate is calculated from the design calculated LPEGR gas volume, the MAF reports the correct expected air flow. The trouble is, the LPEGR gas flow is restricted and results in a combined actual gas flow being low.
You can overlay all the other relevant data (as I have done) to look for any other possible influences, but I could not see any that stood out. I have excluded all other parameters from displaying on these graphs for the sake of clarity.
My conclusion is that the DPF is obviously broken (that is undeniable as there is soot downstream), and this has caused the LPEGR cooler to be gradually filling with soot and restricting the LPEGR gas flow. This results in under-boost due to incomplete total gas volume at the inlet of the turbo, and under high demand conditions will create a large enough boost difference to generate fault codes, resulting in protective limp mode.
The important consideration is that the new LPEGR cooler will eventually have the same issue down the track as the DPF has not been replaced. Not only that, but as you have seen the soot gets into the turbo, and that will flow through the intercooler and interconnecting hoses. According to FIAT’s own Service News 10.023.19 the DPF must be replaced at the same time.
Hope that you now have trouble free motoring, but I would be considering what to do about the DPF and perhaps checking the intercooler for any soot. I wonder how FIAT would react if you presented the facts to them along with a copy of the 10.023.19 Service news? The mechanics have fixed a symptom of the fault, but not the cause. You may have leverage to obtain some form of compensation for the future labour charges to replace the DPF.
One further point that I think is worth mentioning here is that the analysis and fault diagnostic power of MES is very powerful. Also, because of the complexity and interrelated feedback loops involved, it is vital to not focus in on just one parameter in isolation, but to maintain a very wide-angle view across all parameters to help determine a particular fault.
BEFORE: Speed: 80kph, RPM: 2300
AFTER: Speed: 75 - 95kph, RPM: 1600 – 2400
Done over 300miles now and all good so far with no exhaust soot. As this is the second time I’ve had the DPF out it was a bit easier this time! You can remove the DPF without fully dropping the subframe. ( manual box) - you just remove the subframe bolts and lower it as far as it will go. You don’t have to remove the steering rack bolts or rack. Remove the battery and battery box and it will come out like your delivering a baby!
The DPF mounting brackets are the hard part - they are a bugger to get to. Remove the top o2 sensor to make it easier- remove the alternator exciter connector as that is in the way as well.
I did this on my driveway on stands
Fredastaire
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Hoy desmonté el enfriador EGR y el turbocompresor.
Como era de esperar, el enfriador del enfriador estaba bastante sucio.
En este caso, la falta de potencia y la falla P238 se deben a daños en el turbocompresor. Este daño parece deberse a restos de carbón y al material desprendido de la EGR de baja presión.
Les comparto algunas fotos para que puedan apreciar los daños y el estado de las piezas.
Como era de esperar, el enfriador del enfriador estaba bastante sucio.
En este caso, la falta de potencia y la falla P238 se deben a daños en el turbocompresor. Este daño parece deberse a restos de carbón y al material desprendido de la EGR de baja presión.
Les comparto algunas fotos para que puedan apreciar los daños y el estado de las piezas.
Attachments
English translation of above valuable information. The findings above would indicate that the sooner a damaged DPF is detected and replaced the better. Thanks for sharing @Dexron . @jansla Food for thought. As a reminder, Dexron's engine is a 2.3, 150 hp, with 580,000 km, with fault P0238. The turbo is the VVT variant.
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My van's DPF shows no apparent damage, but it does have carbon deposits and a dirty exhaust.
This carbon buildup could be due to a malfunctioning turbocharger.
I'm still thinking about removing the low-pressure EGR system and drawing clean air from the filter. My fear is that the EGR temperature sensor will detect a malfunction and trigger the engine failure.
This carbon buildup could be due to a malfunctioning turbocharger.
I'm still thinking about removing the low-pressure EGR system and drawing clean air from the filter. My fear is that the EGR temperature sensor will detect a malfunction and trigger the engine failure.
From all accounts it would seem likely that a low reported LPEGR temperature will not be an issue as @Cariou has not reported this as a problem and he is already running a system like what you are proposing. I like the sound of your method - drawing the air from the existing air filter - very smart. If it does create an issue, you could always introduce a temperature offset with a resistor. @Fredastaire has been experimenting with that and may have some information for you if required.
Regarding your DPF. I am interested to know how a DPF can allow soot to pass through if it is not damaged. Is that actually possible? When you say it shows no apparent damage is that from visually inspecting both the inlet side of the filter medium as well as the outlet? The reason I ask is that the outlet side may appear OK, but if the inlet side is damaged, that will allow soot through as well. If both sides look intact, then the filter matrix could be compromised internally.
Fredastaire
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@deejays working from memory, the DPF inlet is akin to a hockey stick profile. You cannot look at the matrix except by having a camera probe.
I'm back after a week away, I'm to have another look at the Cariou system. It's not straightforward to take air from the standard air filter as the U bend plastic duct is the far side of the gearbox. -----im thinking though.......
I'm back after a week away, I'm to have another look at the Cariou system. It's not straightforward to take air from the standard air filter as the U bend plastic duct is the far side of the gearbox. -----im thinking though.......
By removing a straight tube about 4 cm long, I think it's possible to connect a flexible hose, perhaps a drain tube, and route it to the air filter, which surrounds the gearbox.
We'd need to determine which area is most accessible.
@Fredastaire, could you share with me all the information you've gathered from your tests regarding the temperature sensor?
We'd need to determine which area is most accessible.
@Fredastaire, could you share with me all the information you've gathered from your tests regarding the temperature sensor?
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Fredastaire
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Fredastaire
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@Dexron , I wonder if the system has gremlins, I thought at first I'd seen your comments in English, then I looked again; French, look just now and back to English. So, my resistor trials? From previous posts I knew the wire colours, I was looking to open the harness plug but seeing it looked complex I took an easier approach and unpeeled the harness wrapping, bingo, I spotted the two wires for the temp probe. By van is comfortmatic where all the servos hide the actual plug/ socket. I used my soldering iron to melt off a little wire insulation enabling me to solder a new extension wire to each cable, then insulation wrapped.this meant I could add resistors without actually chopping wires. I had already bought a new Fiat temp probe and tested at freezing, ambient and boiling so new it's operational scope. Adding a resistor in parallel makes the ECU see a higher temperature than reality. Adding it at ambient then starting the engine throws a fault code because the engine has completed a self check. So, I went for a drive,with Multiecuscan running and adding different resistances whilst watching the LP EGR operation, result? Even at a crazy 171 degrees I could see no operational change of the LP.
I thus gave up with the experiment.
Why is the probe installed? We have no idea. At least I looked
I thus gave up with the experiment.
Why is the probe installed? We have no idea. At least I looked
Thanks @Fredastaire for the reply.
Do you think I could place the probe in the cold air duct without any error codes?
Do you think I could place the probe in the cold air duct without any error codes?
Fredastaire
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@Fredastaire
I don't think there's enough room to hold the tube that runs from the cooler to the EGR, which houses the temperature sensor. Another option is to connect the wires to the temperature sensor behind the FAP.
I can't find @Cariou's post about his system. Could you please tell me which page it's on?
I don't think there's enough room to hold the tube that runs from the cooler to the EGR, which houses the temperature sensor. Another option is to connect the wires to the temperature sensor behind the FAP.
I can't find @Cariou's post about his system. Could you please tell me which page it's on?
Fredastaire
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@Dexron , Cariou first posted multiple photos about 2 1/2 years back. I've been in contact with him in recent weeks, he sent me the photos however I can't locate them today. I think he also added them on here say 4-8 weeks back.
Fundamentally he undid the clamp ring where the ribbed Flexi pipe attached to the DPF outlet stub, then made a disc to blank the stub re-using the clamp ring. The ribbed Flexi is left in mid-air capped off with a piece of stainless mesh, internal to the Flexi he has stuffed it with stainless wire wool. A basic 'old school' mesh filter. He's been running this way for the last 2 1/2 years fault free. It just draws fresh air from under the van, through the cooler.
Any thoughts welcome.
Fundamentally he undid the clamp ring where the ribbed Flexi pipe attached to the DPF outlet stub, then made a disc to blank the stub re-using the clamp ring. The ribbed Flexi is left in mid-air capped off with a piece of stainless mesh, internal to the Flexi he has stuffed it with stainless wire wool. A basic 'old school' mesh filter. He's been running this way for the last 2 1/2 years fault free. It just draws fresh air from under the van, through the cooler.
Any thoughts welcome.
