C5 HDI Engine runs very erratic

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steenschalls
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C5 HDI Engine runs very erratic

Post by steenschalls »

My C5 2.0 HDI 2006 with paticulate filter has a serious fault and it seems that nobody has heard about it here in Denmark. Each 700 km approximately, the engine starts to run very erratic and partly out of control. This will last for about 10 km, then all is normal , and the engine runs perfect again. I have no engine fault light and with readout on Lexia there are no fault codes. I am sure this fault is related to particulate filter cleaning? Lexia says the filter is in good state

regards
Steen Schalls

VF7**************[VIN obfuscated, can be read by forum staff]
202000 km
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GiveMeABreak
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Re: C5 HDI Engine runs very erratic

Post by GiveMeABreak »

Hi and welcome Steen.

Ok so you have the DW10BTED4 138. Normally, if it is pollution-related, you will get the engine management light on temporarily or permanently, with or without a message. The same with the need to top of the DPF additive fluid.

In you case though it sounds like it might just be the particulate filter regenerating, or trying to regenerate. If you do lots of small trips or stop and start journeys, then the exhaust temperatures may not be getting hot enough to passively regenerate the DPF. The engine management ECU may then initiate a DPF regeneration cycle - but if the car is stopped or interrupted from the cycle, it has to abort and will try the next time the car meets the conditions to attempt it again.

If there is a repeated cycle of missed regenerations, then ultimately as the DPF gets full, the message will be displayed warning you of the risk of the filter clogging.

So, try going for a good run periodically (and as you have and AM6 Auto box keep it in manual mode so you can keep the revs a little higher) and allow the engine to get to operating temperature so that it can attempt an uninterrupted regeneration.

Other possibilities may be the EGR getting a little clogged - but anything more serious should result in an engine management fault code being logged.
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moizeau
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Re: C5 HDI Engine runs very erratic

Post by moizeau »

Hi Steen, have a read of the thread 'hiccuping 407' I had the same thing. It's a vacuum leak from the solenoid above the A/c compressor, or a sticky doser butterfly.
https://www.frenchcarforum.co.uk/forum/ ... =4&t=60390
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moizeau
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Re: C5 HDI Engine runs very erratic

Post by moizeau »

Just to update, I've just learnt that the X7 C5 butterflies are electrically operated, not vacuum. Not sure on yours? If you have access to Diagbox the butterflies can be tested.
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Re: C5 HDI Engine runs very erratic

Post by steenschalls »

Hallo
Thank you for the quick replies. The reply from Moizeau is very interesting and I will go and check today. I missed where excactly you found the leak? I already had a leak in a cracked Y union on the front of the engine not far from the solenoid valve you mention. This leak caused serious engine power loss.

regards
Steen
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moizeau
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Re: C5 HDI Engine runs very erratic

Post by moizeau »

If it's the same as mine, and the butterflies are vacuum pipe controlled, the vacuum solenoids are mounted on top of the A/C compressor. The pipes are about 8mm in diameter. If you look through the thread I posted there is a link to another thread on the Peugeut forum. This has pictures. If you have access to a Lexia / Diagbox then they can be checked using the actuator tests in, I think, the Injection ECU. You can also check the movement of the butterflies by taking the pipes off each solenoid and sucking. Each solenoid has 2 pipes. 1 is the vacuum supply and the other moves the butterfly. It's the second that you suck on. Do 1 pipe at a time so they go back in the correct place.. Also if you have the 2 butterfly set up like mine, remove the large pipes to gain access to them, stick a finger up to the butterfly. 1 should be normally open, the other closed, you should be able to move them with your finger against the spring and they should return to the normal position freely. During regen they change to bypass the intercooler. On mine the normally open was closing (operated by the solenoid farthest away from the aux belt) and the normally closed WASN'T opening (solenoid closest to the aux belt), hence no air getting in and the engine tries to stall. The engine then realises this and re-opens the normally open butterfly, which then resumes normal engine performance, the cycle then repeats every few seconds causing a kangaroo effect. It is a commonish fault. I simply put a small solid pipe (actually a clear return pipe from the BX) inside the the black vacuum pipe then another length of black rubber pipe (1 cm) onto the clear pipe and connected it to the solenoid. The original pipe gets hard with over time and doesn't seal properly to the solenoid output. You will know this when you unplug it because it will take very little effort to pull the pipe off.
Best of luck and let us know how it goes.
steenschalls
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Re: C5 HDI Engine runs very erratic

Post by steenschalls »

Thank you for the very detailed information. I have the same engine and system as you have. My wife has unfortunately forbidden me to go and spend more time on my car the next couple of days due to the xmas holidays. As soon as I am released I will follow your recommendations and come back with an update.

merry christmas

Steen
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Re: C5 HDI Engine runs very erratic

Post by steenschalls »

Yesterday I installed new vacuum tubes to and from the electrovalve and to the two butterfly valves in the air inlet. Today I took the car for a test run, and after 655 km since last regeneration, a new regeneration started. And the engine ran smootly throughout the entire particulate filter cleaning process. So for sure the fault was leaking vacuum hoses. Thank you indeed for the great help I have had.

regards
Steen
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moizeau
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Re: C5 HDI Engine runs very erratic

Post by moizeau »

Splendid result, glad my problem and consequent research has helped you sort it easily with minimum cost, and thanks for getting back with the good news.
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EDC5
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Re: C5 HDI Engine runs very erratic

Post by EDC5 »

^^ yes, excellent to hear that the issue was resolved.

I'm glad I've got the single doser version of this engine that doesn't feel the need to close mid regeneration :o
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moizeau
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Re: C5 HDI Engine runs very erratic

Post by moizeau »

Not an issue though now Elis and the fact that the newer cars also have twin dosers must mean mine was ahead of it's time and possibly a test for the future. You know you want it!