Technical Ducato P0401 P0402 P0236 P0238 and limp mode its 2017 Euro 6, EGR changed, What do I check next

[deejays]

@jansla I am very much thinking there may be two issues at play here. One is a blocking cooler, and the other is there is something amiss with the Turbo Actuator Command. So, perhaps both the chicken and the egg are in play. And speaking earlier of reverse engineering, I suspect we (at least I) have got the direction of the Turbo Actuator Command in reverse. What I mean by that, is that at start up, and very low load demands (idling engine for example) the value is always high - near 100%. So I think it is reverse logic that applies to this signal, and that is a high number means very little to no influence on the boost mechanism, and the lower the number goes then there is more control exerted over the boost function. What also reinforced our original thinking was that when the fault flags, and the vehicle enters limp mode, that number falls to 0. But I think in this situation, it means nothing other than all boost is off - including any sort of EGR as all values fall to 0. The engine is then operating as a non-turbo diesel with no EGR and probably plenty of other restrictions.
This thinking has led me to carry out another test run on my vehicle with the revised template (applicable to the 150/180 engine) and the response of that signal on my vehicle confirms that suspicion. I will post the details later as I have other fish to fry right now (literally - it's dinner time!). What would be of the absolute benefit for you would be for some kind soul who has a faultless 130HP engine to run the revised template and post the CSV file for you.
I will post mine and some screen shots after dinner - you might be surprised by what you see.

 

[jansla]

@jansla , I think you have uploaded older files that you have previously uploaded and not the new template ones as intended.

asch! You are right! It was a very busy day for me yesterday and I made mistake, sorry for that, Here comes correct ones from yesterday, first with fault and limp mode second sfter resetti g

 

[deejays]

@jansla The following is for my 150HP, one would hope it gives an indication of what should be expected of the 130HP. The Turbo Actuator Command starts out at the same place, but for the healthy engine is modulating around the 50% mark (which does make a lot of sense). The Actual Boost tracks very closely the desired Boost. The LPEGR Temperature rises quickly, and the Inlet Manifold Temperature is modulating around the 55C mark. There is minimal HPEGR input, and the LPEGR valve is modulating around mid-travel, never full open, and not flat-lining.

Overview:

Cold start to 750 seconds:

975 to 1263:

975 to 1263:

 

[jansla]

@jansla The following is for my 150HP, one would hope it gives an indication of what should be expected of the 130HP. The Turbo Actuator Command starts out at the same place, but for the healthy engine is modulating around the 50% mark (which does make a lot of sense). The Actual Boost tracks very closely the desired Boost. The LPEGR Temperature rises quickly, and the Inlet Manifold Temperature is modulating around the 55C mark. There is minimal HPEGR input, and the LPEGR valve is modulating around mid-travel, never full open, and not flat-lining.

Overview:
View attachment 467248

Cold start to 750 seconds:
View attachment 467249

975 to 1263:
View attachment 467250

975 to 1263:
View attachment 467251

@deejays Yes! I agree. It makes sense! Absolutely. This way all parameters are connected and behave as expected. No doubt that in my case turbo will not or can not deliver what it is asked for (this is the most obvious now) and the temperatures show unexpected values. Difficult to go any further with analysis and the next step should be to look closely at turbo and LPEGR cooler, and as we well know this can not be done by DIY-er by himself (myself). Wednesday next week (appointment in the garage) is going to be the beginning of a new chapter - hopefully.

 

[deejays]

@deejays Yes! I agree. It makes sense! Absolutely. This way all parameters are connected and behave as expected. No doubt that in my case turbo will not or can not deliver what it is asked for (this is the most obvious now) and the temperatures show unexpected values. Difficult to go any further with analysis and the next step should be to look closely at turbo and LPEGR cooler, and as we well know this can not be done by DIY-er by himself (myself). Wednesday next week (appointment in the garage) is going to be the beginning of a new chapter - hopefully.

Have you tried running the Actuator Test in MES for the Boost control solenoid and at the same time observe the linkage from the actuator to the turbo to see if it actually moves?

 

[Fredastaire]

@jansla I would suggest that you can DIY inspect the cooler yourself. With the van up on ramps you can lie down and wriggle underneath. There is a stainless flexible pipe from the DPF outlet to the LP EGR inlet pipe. The Flexi has a special clamp with a single clamp screw (13mm af head). You can easily undo the clamp screw and remove it. Then refit with two M8 standard nuts in the middle. Screwing the nuts opposite ways expands the clamp to open it up and release the Flexi
You could then slide an endiscope upwards to inspect.
I've had an endiscope up my removed/ cleaned cooler, I've undone the clamp on my Ducato, just not done the above endoscopy on my van itself.

 

[Fredastaire]

I've done another trial on the LP EGR temp sensor. We don't know what it's there for. I was wondering if it was used to control the LP EGR opening either graduated or as a high temp policeman to prevent high temp exhaust reaching the turbo. I've added different resistance values in parallel with the sensor wires to send a wrong high temperature to the ECU. I've got as far as a false temperature of 160 degrees but the EGR is still modulating. I've yet to do a road run with CSV recording before I finally give up. At best I will have answered a question.
.
We still need a way of shutting the LP EGR off without a software delete.
.
I've still in mind the mod by Cariou.....

 

[jansla]

@jansla I would suggest that you can DIY inspect the cooler yourself. With the van up on ramps you can lie down and wriggle underneath. There is a stainless flexible pipe from the DPF outlet to the LP EGR inlet pipe. The Flexi has a special clamp with a single clamp screw (13mm af head). You can easily undo the clamp screw and remove it. Then refit with two M8 standard nuts in the middle. Screwing the nuts opposite ways expands the clamp to open it up and release the Flexi
You could then slide an endiscope upwards to inspect.
I've had an endiscope up my removed/ cleaned cooler, I've undone the clamp on my Ducato, just not done the above endoscopy on my van itself.

I’ve opened that flexi for inspection before the summer last year. I have had borrowed inspection camera so I could have a look att the bottom of the DPF (was quite ok, not that sooty as the exhaust pipe outlet) but I couldn’t reach any further

 

[jansla]

@jansla The following is for my 150HP, one would hope it gives an indication of what should be expected of the 130HP. The Turbo Actuator Command starts out at the same place, but for the healthy engine is modulating around the 50% mark (which does make a lot of sense). The Actual Boost tracks very closely the desired Boost. The LPEGR Temperature rises quickly, and the Inlet Manifold Temperature is modulating around the 55C mark. There is minimal HPEGR input, and the LPEGR valve is modulating around mid-travel, never full open, and not flat-lining.

Overview:
View attachment 467248

Cold start to 750 seconds:
View attachment 467249

975 to 1263:
View attachment 467250

975 to 1263:
View attachment 467251

@deejays I was thinking about how to compare our engines which although not exactly the same differ only by 20HP from the factory and considering my tuning maybe not even that much. I compared what was recorded in your csv file from 2505191149 with mine after removing errors 2505181724. Lots of similarities. But not all parameters are the same. I tried to compare different speed ranges but in the end I chose to compare the records that each of us obtained by setting the condition that the gas pedal was pressed 40% or more. Then usually the engine works under some load, overcomes the resistance or accelerates. It did not look like there were any extreme conditions but just normal driving. Smaller loads can give differences resulting from how hard you accelerate, but above 40% gas pedal it can be assumed gives similar conditions.

So I filtered those rows from csv files where the pressure on the accelerator was 40% or more. For each recorded parameter after filtering I calculated the average values and compared them. Most looked similar. There were clear differences in the difference between the desired and current boost pressure. In my file there was an underboost of 180mbar on average and in yours no significant difference. The average boost value in your case was greater by about 300mbar copared to mine. HPEGR was rather closed in both cases, LPEGR in your 1.6 in my 4.3, i.e. mine tended to be constantly open.

In my opinion, the results regarding the amount of air flowing through the MAF sensor are interesting. If I'm not mistaken, the MAF is located between the air filter and the LPEGR valve, which means it only reads what reaches the turbo through the air filter.
Before entering the turbo, this clean air mixes with the dirt gases that the LPEGR valve makes available. There is a butterfly valve there that supposedly cuts off the air from the air filter. But does it completely? If the gases from the LPEGR cooler were blocked due to the LPEGR cooler being clogged, nothing would pass through when the LPEGR valve was opened. And the butterfly valve would cut off the air from the air filter. The engine should choke and stop. However, this is not happening in my case. Look at the MAF sensor reading. It goes about the same as in your engine.
And this is what puzzles me and raises doubts as to whether the LPEGR is really clogged. If air cannot get through the LPEGR because it is clogged and opening the LPEGR valve is supposed to close access to air from the filter, where does this air come from? The system is tight, which was checked. So is the LPEGR really clogged? This results from observing temperatures. However, compressed air has a higher temperature than the same air at lower pressure. Well, I don't know how much higher, but probably higher. Your turbo has a greater compression effect than mine. This may give a higher temperature. If the LPEGR does not let through as much gas as it should, more should be taken from the filter.
A comparison of your and my parameters shows that these are similar amounts of air taken to manifold, measured by MAF and even a little more in your case, and it should be the other way around if LPEGR was clogged.
While the difference in our parameters clearly indicates that my boost is too low, I don't know if it is just as obvious an indication of LPEGR cooler obstruction, although it is quite possible. Why is lambda oxygen after DPF twice as large in your case compared with mine? What do you think about these differences?

 

[deejays]

I've done another trial on the LP EGR temp sensor. We don't know what it's there for. I was wondering if it was used to control the LP EGR opening either graduated or as a high temp policeman to prevent high temp exhaust reaching the turbo. I've added different resistance values in parallel with the sensor wires to send a wrong high temperature to the ECU. I've got as far as a false temperature of 160 degrees but the EGR is still modulating. I've yet to do a road run with CSV recording before I finally give up. At best I will have answered a question.
.
We still need a way of shutting the LP EGR off without a software delete.
.
I've still in mind the mod by Cariou.....

Reverse engineering is a challenge! From observation, the LPEGR valve is barred from opening until an external temp sensor gets to a certain point. That sensor may be the Temperature after the particle filter sensor as it is the temperature of the gases entering the cooler. Then there may be a number of sensors driving the actual opening amount of the LPEGR valve. The main suspects would be the O2 and exhaust gas temperatures. EGR attempts to reduce the combustion O2 levels and temperatures. I suspect the LPEGR temp sensor to be a max temp limit to shut the valve (policeman) to protect the rest of the system and also would form part of the fast regulatory circuit. The LPEGR has been observed to operate during a DPF regen with elevated exhaust temps, and I suspect the temp limit for the policeman is lowered during the regen as the rate of LPEGR temp increase is so rapid. The LPEGR valve only spikes open briefly during the regen.

 

[deejays]

I’ve opened that flexi for inspection before the summer last year. I have had borrowed inspection camera so I could have a look att the bottom of the DPF (was quite ok, not that sooty as the exhaust pipe outlet) but I couldn’t reach any further

The pipe you need to insert the borescope into is the one leading to the cooler, not the DPF to exhaust pipe junction. The photo below showing the "aftermarket" wire mesh. The pipe you need to insert the borescope into is the one covered by the wire mesh.

 

[deejays]

@deejays I was thinking about how to compare our engines which although not exactly the same differ only by 20HP from the factory and considering my tuning maybe not even that much. I compared what was recorded in your csv file from 2505191149 with mine after removing errors 2505181724. Lots of similarities. But not all parameters are the same. I tried to compare different speed ranges but in the end I chose to compare the records that each of us obtained by setting the condition that the gas pedal was pressed 40% or more. Then usually the engine works under some load, overcomes the resistance or accelerates. It did not look like there were any extreme conditions but just normal driving. Smaller loads can give differences resulting from how hard you accelerate, but above 40% gas pedal it can be assumed gives similar conditions.

So I filtered those rows from csv files where the pressure on the accelerator was 40% or more. For each recorded parameter after filtering I calculated the average values and compared them. Most looked similar. There were clear differences in the difference between the desired and current boost pressure. In my file there was an underboost of 180mbar on average and in yours no significant difference. The average boost value in your case was greater by about 300mbar copared to mine. HPEGR was rather closed in both cases, LPEGR in your 1.6 in my 4.3, i.e. mine tended to be constantly open.

In my opinion, the results regarding the amount of air flowing through the MAF sensor are interesting. If I'm not mistaken, the MAF is located between the air filter and the LPEGR valve, which means it only reads what reaches the turbo through the air filter.
Before entering the turbo, this clean air mixes with the dirt gases that the LPEGR valve makes available. There is a butterfly valve there that supposedly cuts off the air from the air filter. But does it completely? If the gases from the LPEGR cooler were blocked due to the LPEGR cooler being clogged, nothing would pass through when the LPEGR valve was opened. And the butterfly valve would cut off the air from the air filter. The engine should choke and stop. However, this is not happening in my case. Look at the MAF sensor reading. It goes about the same as in your engine.
And this is what puzzles me and raises doubts as to whether the LPEGR is really clogged. If air cannot get through the LPEGR because it is clogged and opening the LPEGR valve is supposed to close access to air from the filter, where does this air come from? The system is tight, which was checked. So is the LPEGR really clogged? This results from observing temperatures. However, compressed air has a higher temperature than the same air at lower pressure. Well, I don't know how much higher, but probably higher. Your turbo has a greater compression effect than mine. This may give a higher temperature. If the LPEGR does not let through as much gas as it should, more should be taken from the filter.
A comparison of your and my parameters shows that these are similar amounts of air taken to manifold, measured by MAF and even a little more in your case, and it should be the other way around if LPEGR was clogged.
While the difference in our parameters clearly indicates that my boost is too low, I don't know if it is just as obvious an indication of LPEGR cooler obstruction, although it is quite possible. Why is lambda oxygen after DPF twice as large in your case compared with mine? What do you think about these differences?

@jansla @Fredastaire @theoneandonly
It is a brave man that dares to compare direct specific tabulated readings for two different motors driving different GVM vehicles in uncontrolled conditions. Also, the torque curve will be different due to the difference between the two turbos. A VVT will spool up much quicker and provide more bottom end torque for a given controlled condition. If both engines were on the same dynamometer operating under the same operating conditions, then it would be reasonable to compare specific points of operational values, but not in this case. I think what we have been doing, and that is observing with a wide angle lens the overall visual graphics showing the interrelationships between various measured parameters and noting the marked differences is valid.

Regarding the MAF and measured (filtered) air flow. You are correct, and it is something I have observed from the start – and yes, it has puzzled me for a while as well. I suspect there are other things at play here (other sensors) and that may be exhaust temperature and O2 level dependant.

Now, having said that we need to think a bit harder about this important aspect. The measured air flow is matching the desired airflow, yet we are under-boosted overall and if driven hard enough, will throw a fault code and trigger protective limp mode. So, the matched airflow reading!? I am advocating that the value of the desired intake air quantity parameter is dependent on the desired position of the LPEGR valve (among other things). And if the actual position of the LPEGR valve matches the desired position, then if there are no blockages (apart from the calibrated LPEGR valve) in the filtered air path from the air filter to the input of the turbo, then the actual airflow will match the desired air flow (for the current position of the LPEGR valve!). The issue is that the ECU mapping for all this considers that there is no LPEGR cooler blockage and there is the correct amount of EGR gas flowing. The trouble is, with a blocked cooler, there is not. This results in insufficient gas volume for the ECU mapped point of operation and the engine is effectively strangled and the actual boost cannot achieve the desired boost! Note that the engine is strangled not due to the lack of (ECU mapped) volume of fresh filtered air, but from the lack of volume of EGR due to the blocked or blocking cooler. So, the original explanation by Fred is correct, to a point – the engine is being strangled, but not as first thought by shutting off the desired amount of fresh air, but by not having the volume of LPEGR gas to make up the total desired volume of gas!

The above “Reverse Engineering on the fly” also explains why in your CSV examples that the turbo actuator command comes good very briefly and when it does on most occasions that is when the LPEGR is sharply closing from full open allowing the boost to normalise (in that brief moment) because the correct volume of calibrated gas is flowing (the EGR is shut/shutting, so all the gas is fresh air and the air flow is correct for the given conditions).

So, I am going to be bold and predict that your problem is a blocking cooler, and that is probably it – nothing else.

This also explains why disconnecting a clean LPEGR cooler from the DPF and fitting an air filter to allow fresh air in via the cooler works – the gas volume is matching all round. The downside of doing this is that the engine is converted to a single HPEGR and because of that there will be a significant increase in soot loading on the inlet manifold, throttle body and HPEGR valve and associated components as the HPEGR will now be called upon to make up the difference in EGR gas volume. One would also expect the oil and engine life to be affected.

Regarding your timing/distance/engine temperature dependence of the initial fault occurring – is it perhaps actually related to percentage gas pedal opening (engine warmed up – let’s go!) and thus creating a large enough discrepancy between actual boost and desired boost (particularly at high overall boost level) to trigger the fault and protective limp mode?

You asked: “Why is lambda oxygen after DPF twice as large in your case compared with mine?” I think the answer is in the above.

 

[jansla]

@jansla @Fredastaire @theoneandonly
It is a brave man that dares to compare direct specific tabulated readings for two different motors driving different GVM vehicles in uncontrolled conditions. Also, the torque curve will be different due to the difference between the two turbos. A VVT will spool up much quicker and provide more bottom end torque for a given controlled condition. If both engines were on the same dynamometer operating under the same operating conditions, then it would be reasonable to compare specific points of operational values, but not in this case. I think what we have been doing, and that is observing with a wide angle lens the overall visual graphics showing the interrelationships between various measured parameters and noting the marked differences is valid.

Regarding the MAF and measured (filtered) air flow. You are correct, and it is something I have observed from the start – and yes, it has puzzled me for a while as well. I suspect there are other things at play here (other sensors) and that may be exhaust temperature and O2 level dependant.

Now, having said that we need to think a bit harder about this important aspect. The measured air flow is matching the desired airflow, yet we are under-boosted overall and if driven hard enough, will throw a fault code and trigger protective limp mode. So, the matched airflow reading!? I am advocating that the value of the desired intake air quantity parameter is dependent on the desired position of the LPEGR valve (among other things). And if the actual position of the LPEGR valve matches the desired position, then if there are no blockages (apart from the calibrated LPEGR valve) in the filtered air path from the air filter to the input of the turbo, then the actual airflow will match the desired air flow (for the current position of the LPEGR valve!). The issue is that the ECU mapping for all this considers that there is no LPEGR cooler blockage and there is the correct amount of EGR gas flowing. The trouble is, with a blocked cooler, there is not. This results in insufficient gas volume for the ECU mapped point of operation and the engine is effectively strangled and the actual boost cannot achieve the desired boost! Note that the engine is strangled not due to the lack of (ECU mapped) volume of fresh filtered air, but from the lack of volume of EGR due to the blocked or blocking cooler. So, the original explanation by Fred is correct, to a point – the engine is being strangled, but not as first thought by shutting off the desired amount of fresh air, but by not having the volume of LPEGR gas to make up the total desired volume of gas!

The above “Reverse Engineering on the fly” also explains why in your CSV examples that the turbo actuator command comes good very briefly and when it does on most occasions that is when the LPEGR is sharply closing from full open allowing the boost to normalise (in that brief moment) because the correct volume of calibrated gas is flowing (the EGR is shut/shutting, so all the gas is fresh air and the air flow is correct for the given conditions).

So, I am going to be bold and predict that your problem is a blocking cooler, and that is probably it – nothing else.

This also explains why disconnecting a clean LPEGR cooler from the DPF and fitting an air filter to allow fresh air in via the cooler works – the gas volume is matching all round. The downside of doing this is that the engine is converted to a single HPEGR and because of that there will be a significant increase in soot loading on the inlet manifold, throttle body and HPEGR valve and associated components as the HPEGR will now be called upon to make up the difference in EGR gas volume. One would also expect the oil and engine life to be affected.

Regarding your timing/distance/engine temperature dependence of the initial fault occurring – is it perhaps actually related to percentage gas pedal opening (engine warmed up – let’s go!) and thus creating a large enough discrepancy between actual boost and desired boost (particularly at high overall boost level) to trigger the fault and protective limp mode?

You asked: “Why is lambda oxygen after DPF twice as large in your case compared with mine?” I think the answer is in the above.

I actually agree that comparing two engines in uncontrolled conditions is inappropriate and does not allow for drawing conclusions. However, understand that since 2023, no specialized mechanic has been able to solve my problem. I pay them and what do they do? After all, the combustion engine, despite being highly advanced, is not rocket science, nor does it have problems with mutations of complex genes, cellular immunity systems, etc. Nor any supernatural powers. It was created by people and it is certainly possible to solve it. Therefore, do not be surprised that I am trying to review the data I have access to in various ways.

Your latest explanations are convincing. As a result, I ordered a new turbo and LPEGR cooler and they will be replaced on Wednesday next week. It will be interesting to see what these old parts look like when removed from the engine and see how it affects the parameters recorded in MES after replacement. Even more interesting will be how it will affect the occurrence of my errors. Time will tell.

Let me address one more issue. You say that it is only a blocked LPEGR cooler and nothing else. Yes, it is indeed possible. However, I have never had P0401 P0402 as in the title of this thread, only P0236 and P0238 constantly and every time. This is a bit puzzling because many of the cases described here where a blocked LPEGR cooler was found also had 401. And one more thing. Looking at the cross section area of the intake pipe to the LPEGR cooler, you can see that it is clearly smaller than the pipe supplying fresh air from the air filter. I still don't know to what extent the butterfly valve can cut off access to clean air, but it seems that it doesn't cut off completely because the engine produces power, does not stall and runs, although the cooler does not let any gases through. If the LPEGR valve is designed in such a way that in the open position the mechanically connected butterfly valve in the supply pipe from the air filter is closed, where does what gets into the combustion chamber come from when the cooler is clogged? The ECU does not know that exhaust gases do not enter because they have a clogged cooler. It calculates the desired air flow knowing or rather assuming that part of the volume goes from the LPEGR and one could expect that the actual air flow (from MAF) would be greater than desired in the case of a clogged cooler, and it is mostly exactly as desired.

What is the purpose of letting exhaust gases into the intake? Lowering the combustion temperature. At high temperatures, more harmful nitrogen oxides are produced. If my LPEGR, although open, does not letting exhaust gases when the ECU expects it, because it is clogged, then more oxygen goes to the combustion chamber and the combustion temperature should go up. There will be more nitrogen oxides. The exhaust gases will not meet the standards. This is checked during annual inspections and there has never been a problem with it. Your explanation that the gas volume is too small to achieve boost makes sense, but when I press the gas pedal to the floor, the 3.5 tons accelerates without a problem to 130 km/h and no error appears. That is why it is so difficult for me to accept that the cooler is clogged, although it is possible.

These are just considerations for the sake of this discussion, another point of view, although I know I don't have enough technical background to know if I'm right.

 

[deejays]

I actually agree that comparing two engines in uncontrolled conditions is inappropriate and does not allow for drawing conclusions. However, understand that since 2023, no specialized mechanic has been able to solve my problem. I pay them and what do they do? After all, the combustion engine, despite being highly advanced, is not rocket science, nor does it have problems with mutations of complex genes, cellular immunity systems, etc. Nor any supernatural powers. It was created by people and it is certainly possible to solve it. Therefore, do not be surprised that I am trying to review the data I have access to in various ways.

Your latest explanations are convincing. As a result, I ordered a new turbo and LPEGR cooler and they will be replaced on Wednesday next week. It will be interesting to see what these old parts look like when removed from the engine and see how it affects the parameters recorded in MES after replacement. Even more interesting will be how it will affect the occurrence of my errors. Time will tell.

Let me address one more issue. You say that it is only a blocked LPEGR cooler and nothing else. Yes, it is indeed possible. However, I have never had P0401 P0402 as in the title of this thread, only P0236 and P0238 constantly and every time. This is a bit puzzling because many of the cases described here where a blocked LPEGR cooler was found also had 401. And one more thing. Looking at the cross section area of the intake pipe to the LPEGR cooler, you can see that it is clearly smaller than the pipe supplying fresh air from the air filter. I still don't know to what extent the butterfly valve can cut off access to clean air, but it seems that it doesn't cut off completely because the engine produces power, does not stall and runs, although the cooler does not let any gases through. If the LPEGR valve is designed in such a way that in the open position the mechanically connected butterfly valve in the supply pipe from the air filter is closed, where does what gets into the combustion chamber come from when the cooler is clogged? The ECU does not know that exhaust gases do not enter because they have a clogged cooler. It calculates the desired air flow knowing or rather assuming that part of the volume goes from the LPEGR and one could expect that the actual air flow (from MAF) would be greater than desired in the case of a clogged cooler, and it is mostly exactly as desired.

What is the purpose of letting exhaust gases into the intake? Lowering the combustion temperature. At high temperatures, more harmful nitrogen oxides are produced. If my LPEGR, although open, does not letting exhaust gases when the ECU expects it, because it is clogged, then more oxygen goes to the combustion chamber and the combustion temperature should go up. There will be more nitrogen oxides. The exhaust gases will not meet the standards. This is checked during annual inspections and there has never been a problem with it. Your explanation that the gas volume is too small to achieve boost makes sense, but when I press the gas pedal to the floor, the 3.5 tons accelerates without a problem to 130 km/h and no error appears. That is why it is so difficult for me to accept that the cooler is clogged, although it is possible.

These are just considerations for the sake of this discussion, another point of view, although I know I don't have enough technical background to know if I'm right.

Hi @jansla I have not said that you have a blocked cooler. I am suggesting that from all the data available it would seem likely that the cooler is on the way to being blocked. I have only referred to a blocking cooler, not blocked; and that it is indeed still passing hot gases. From the data it would seem that the gas flow is not enough - witness the action of the LPEGR valve and also the temperature of the inlet manifold.

I also understand your frustration regarding what appears to be a lack of understanding from the trade mechanics. It is fortunate that Fred and theoneandonly worked out what the underlying issue is.

 

[deejays]

@jansla If it is discovered that the cooler is indeed blocking up, and the DPF is damaged, then consideration should be given to replacing the DPF as it will be removed from the vehicle to gain access to the cooler etc. A damaged DPF, allowing soot to pass will eventually cause blocking of the cooler.

 

[Dexron]

I bought a refrigerator, and after cleaning it, only the edges of the fins remain free.
Could someone who's built a new one tell me if the spaces between the small fins should be clean enough to allow light to pass through?

 

[Fredastaire]

@theoneandonly , you have a new unused cooler, can you do the light bulb test and repeat the above photo? I've only a 'cleaned' originally blocked cooler to hand.

 

[deejays]

@Fredastaire @jansla @theoneandonly
Fred has recently sent me a CSV file of his engine asking how it compares to the data from jansla’s engine as he suspects there may be similarities.

One important thing to note is this is a 130HP engine, so same variant as jansla’s.

It was recorded last August, and it was just prior to him changing the cooler in October.

The reason he changed the cooler, was because he believed that it was becoming blocked enough to affect the engine performance. It had not reached the stage of throwing the dash MIL light at the time the CSV file was recorded. He has given me permission to report on this forum.

Although the parameter template used is not identical, there are enough common parameters to enable the following graph to be captured for comparison. One of the important parameters not recorded was the inlet manifold temperature. None the less, what is apparent from the graph is it shows this engine displaying very similar characteristics as the jansla engine.

Overall, the boost is down some 7%, so not yet near the approximately 11% of the jansla engine. One of the important points to note is that it displays identical characteristics that when the LPEGR valve suddenly closes we can see that the boost immediately returns to normal, identical to the characteristics displayed by the jansla engine.

The LPEGR temperature can also be observed to reach what appears to be normal high temperatures.

It is my understanding that Fred has only replaced the cooler and still has the damaged DPF in situ – understanding that it means replacing/cleaning the cooler on an ongoing basis when it begins blocking again. It is also my understanding that Fred’s engine is still running with the original turbo – it has never been replaced. Fred, is that correct? Could you please confirm?

 

[Fredastaire]

Yes, original turbo. I ordered the van new special build from the factory. I've maintained from new. Only parts replaced were, early in the HP EGR because the fault code said so, (now known to be red herring); the MAP; turbo solenoid twice (only because I suspected it), cooler twice, first because it was totally blocked, second time because I suspected it at the time it was due at the garage for MOT and it would be on the H ramp. I also removed to clean the intercooler just after the first cooler change, I'm thinking of doing it again. My garage said to only flush with petrol as the cooler fins could be damaged by something harsher.
Ive just proved fiddling the LP EGR temp probe hasn't had any effect. I'm seriously looking at the Cariou pipe mods to atmosphere. Also wondering about investigating the DPF canister last temp probe..

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Any other ideas anybody???

 

[jansla]

@Fredastaire would you mind sharing your csv files registered directly after you changed LPEGR cooler?