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2.7 HDI hesitation (not sure if its correct word)
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joopajaa   
Fri Jun 08 2018, 10:46am
Joined: Sep 06 2017
Member No: #3261
Location: Byroslavia, FIN
 Hi I have a large DIY job coming in a form of a cam belt change. I also ordered the thermostat housing and new aux belt etc. Anyway my car has a little hesitation specially in cold weather. I can hear turbo whistle also when cold. My intercooler hoses are oily - at least there is some on the joints.

So the question is: is there some IC piping that is generally failing with these? I guess I can check quite a lot of places when I remove the stuff for cam belt. I have a feeling there is a failed plastic intecooler or intake piping on my car (the whistle). The car does not smoke or eat oil - even with cold engine so I think the turbos should be quite OK. There is 230 tkm on the clock.

I have blocked EGRs earlier with ECU tuning done also. No problems earlier (well the ECU tuning was done do override EGR-valve fault).
C6Dave   
Fri Jun 08 2018, 02:26pm

Joined: Oct 01 2009
Member No: #1
Location: Northumberland
My intercooler hoses are oily - at least there is some on the joints

I asked My local car mechanic about the intercooler hose leak where it connects to the cooler itself because of the New MOT regs and oil leaks and he said 'they all do that' so there isn't an MOT problem.

Turbo whistle tends to be from the turbo itself, not the hoses as far as I am aware, but someone may know different..... but check that the oil feed to the turbo is clear, most turbo fails on the C4 forum were down to blocked oil feed pipes.
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joopajaa   
Tue Jun 12 2018, 06:16am
Joined: Sep 06 2017
Member No: #3261
Location: Byroslavia, FIN
 Update: this problem is present also when warm engine. Low speed or high speed. Seems the problem is on 1600-1800rpm. Seems better on high rpm. Can it be a faulty or clogged injector?

To better describe: when cruising stable speed you can feel the engine doing lower and higher rpm so the whole car feels like you have oval shaped tyre. Wobble? Tremble? Shudder? Not sure the right word..


This is not "hesitation" in a sense of accelerating - engine feels OK and no delays etc on response (well at least no more than common with citroen's AM6 ecu tuning).

This can even be gearbox related I think. Maybe I now use my 12L of 3309 Mannoil..

I have to do some lexianing - any ideas how to test injectors with it?
arconell3   
Tue Jun 12 2018, 12:28pm
Joined: Jun 28 2012
Member No: #922
Location: Kalkar
 The oily intercooler hoses are caused by the sump ventilation (oil-gas separator) not working properly/dirty/clogged up. The oil eventually gets into the butterfly housing, fouling up the whole air intake system.

All of which of course negatively influences combustion quality, making things progressively worse. The gearbox, which is among other things, engine torque controlled, reacts nervously to the resulting small variations in the torque/rev counts, causing a rhythmic opening and closing converter clutch.

Clean all the above mentioned parts, including the swirl valves, put in new MAF sensors and air filter, and once cleaned, use premium diesel fuel only to keep them clean.

Regards, Robert
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321dave   
Tue Jun 12 2018, 01:52pm
Joined: Sep 09 2011
Member No: #614
Location: Dublin
arconell3 wrote ...

The oily intercooler hoses are caused by the sump ventilation (oil-gas separator) not working properly/dirty/clogged up. The oil eventually gets into the butterfly housing, fouling up the whole air intake system.

All of which of course negatively influences combustion quality, making things progressively worse. The gearbox, which is among other things, engine torque controlled, reacts nervously to the resulting small variations in the torque/rev counts, causing a rhythmic opening and closing converter clutch.

Clean all the above mentioned parts, including the swirl valves, put in new MAF sensors and air filter, and once cleaned, use premium diesel fuel only to keep them clean.

Regards, Robert


That explains a lot, I replaced the sensor in the butterfly housing due to a crack and it was putting up engine codes for air pressure. It was all caked up badly. In fact I need now to clean the butterfly housing. Is the problem on the top of the engine where hoses meet at a venting box (beside the oil filter housing)?
arconell3   
Tue Jun 12 2018, 02:46pm
Joined: Jun 28 2012
Member No: #922
Location: Kalkar
321dave wrote ...

That explains a lot, I replaced the sensor in the butterfly housing due to a crack and it was putting up engine codes for air pressure. It was all caked up badly. In fact I need now to clean the butterfly housing. Is the problem on the top of the engine where hoses meet at a venting box (beside the oil filter housing)?


Yes, that should be the venting tubes coming from the 2 cylinder heads.

Regards, Robert
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joopajaa   
Tue Jun 12 2018, 06:16pm
Joined: Sep 06 2017
Member No: #3261
Location: Byroslavia, FIN
 I have a suspect now: MAF senser (rear). There is a large difference on those 2. I tried to clean them with electric cleaner without any luck.

I'm not sure if its related but I have deleted the butterfly valve (and EGR's) and also used a intake cleaner solvent but the intake did not look too messy anyway before that.




EDIT: it seems 2.7 has same MAF sensor as 2.0 Hdi.. Maybe I try one from my wifes car. This can also be the leak in intake piping I suspected in the first place - it would explain the whistle and the MAF reading error.
arconell3   
Wed Jun 13 2018, 09:59am
Joined: Jun 28 2012
Member No: #922
Location: Kalkar
 Compare the MAF sensor part numbers first before swapping the 2.2>2.7. Otherwise the MAF values may be different. The turbo whistle most likely is also caused by oily deposits on the turbo compressor and probably on the turbine wheel as well. Almost all 2.7's I have heard that use regular diesel fuel have this whistle. Most prominent on a cold engine, but still audible when warm.

Regards, Robert
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joopajaa   
Wed Jun 13 2018, 11:32am
Joined: Sep 06 2017
Member No: #3261
Location: Byroslavia, FIN
arconell3 wrote ...

Compare the MAF sensor part numbers first before swapping the 2.2>2.7. Otherwise the MAF values may be different. The turbo whistle most likely is also caused by oily deposits on the turbo compressor and probably on the turbine wheel as well. Almost all 2.7's I have heard that use regular diesel fuel have this whistle. Most prominent on a cold engine, but still audible when warm.

Regards, Robert



Yes I will compare. Also I will first try to swap them from front to rear to see if the reading is from the piping or faulty MAF.
vaho   
Wed Jun 13 2018, 07:47pm
Joined: Jun 25 2015
Member No: #2228
Location: Tallinn
 If I remember it correctly you must check the airflow at 2500 RPM. It should roughly be the same front and back. At idle it may be different and on the picture there is not much difference to be worried. To diagnose the MAF just swap them with each other, if the low flow follows the MAF then it is bad, if not, there is no need to replace it.
arconell3   
Wed Jun 13 2018, 09:49pm
Joined: Jun 28 2012
Member No: #922
Location: Kalkar
vaho wrote ...

If I remember it correctly you must check the airflow at 2500 RPM. It should roughly be the same front and back. At idle it may be different and on the picture there is not much difference to be worried. To diagnose the MAF just swap them with each other, if the low flow follows the MAF then it is bad, if not, there is no need to replace it.


Hmm, I don't necessarily agree, the correct MAF values are indeed very important for your engines' health. MAF sensors have a tendency to A) become dirty in time and use, resulting in a (sometimes significantly) reduced airflow, without the BSI being aware of any faulty measurement, and B) while driving the airflow changes continuously and often rapidly. A dirty MAF sensor element cannot register these changes quick enough, which may result in inexplicable little hiccups while driving.

It is one of those things where penny wise indeed means pound foolish.

Regards, Robert
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vaho   
Thu Jun 14 2018, 09:24am
Joined: Jun 25 2015
Member No: #2228
Location: Tallinn
 Yes they are important, no argument there but the checking procedure is correct:
joopajaa   
Thu Jun 14 2018, 06:55pm
Joined: Sep 06 2017
Member No: #3261
Location: Byroslavia, FIN
vaho wrote ...

If I remember it correctly you must check the airflow at 2500 RPM. It should roughly be the same front and back. At idle it may be different and on the picture there is not much difference to be worried. To diagnose the MAF just swap them with each other, if the low flow follows the MAF then it is bad, if not, there is no need to replace it.


I did try with higher revs when I took the picture and the difference was there. I'll soon try to find time for this subject.
joopajaa   
Thu Jul 05 2018, 07:37pm
Joined: Sep 06 2017
Member No: #3261
Location: Byroslavia, FIN
 OK today I switched front <-> rear MAF and the rear is still lower. A leak on piping I suspect.. I'm doing now timing belt + thermohousing + maybe cleaning intakes (quite stuffed) + maybe taking starter out to clean it inside (weak power imho) -> so maybe I dig this a little deeper also.
joopajaa   
Thu Jul 05 2018, 07:56pm
Joined: Sep 06 2017
Member No: #3261
Location: Byroslavia, FIN
 Question: what is this? Its leaking fuel. Part no? Its under/behind the intake Y, above the thermo housing.





EDIT: Its part no. 1574E8. It seems I need to change the whole piping :/
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