DS4 1.6 e-HDi 9HR/DV6C – jerks and irregular idle, better with the flow meter disconnected

[microlinkro]

Hello everyone,

I have a 2012 Citroën DS4 with the 1.6 e-HDi / HDi 112 hp engine, engine code 9HR / DV6C.

I have been chasing an intermittent rough running issue for some time. The engine starts immediately, but especially when cold it may shake for 1–2 minutes. The main problem appears during transitions: pulling away from traffic lights, light acceleration after slowing down to 30–40 km/h, or gentle acceleration after changing gear. At steady speed the engine runs very well.

I have done several checks with Diagbox and an Autel scanner. The most interesting result is this: when I disconnect the MAF / air flow sensor, the car runs almost perfectly. The hesitation and jerking almost disappear. Of course, with the MAF disconnected I get the expected MAF-related faults, such as P0102 and P0113, and the ECU goes into fallback mode with measured air flow = 0.

When I reconnect the MAF, the rough running comes back.

I also noticed something suspicious. The large corrugated intake hose fitted just after the MAF body moves quite easily on the MAF housing. There is no metal clamp there. I looked at pictures of a compatible VDO/Continental MAF, and the long neck where the hose fits seems completely smooth, with no groove for an O-ring.

My question is:

On this 1.6 e-HDi / DV6C engine, is it normal for the large intake hose after the MAF to be simply push-fitted without a clamp and without a visible O-ring? Should it move quite easily, especially when warm, or should it be tight on the MAF body?

The hose seems to correspond to PSA part number 9683725080. I am wondering if the hose may be old, hardened or enlarged, allowing unmetered air after the MAF and disturbing the EGR/injection strategy.

Has anyone had a similar issue on a DS4 / C4 II / Peugeot 1.6 HDi DV6C?

Thank you.

[Paul-R]

Hello everyone,

I have a Citroën DS4 from 2012, 1.6 e-HDi / 112 hp HDi engine, engine code 9HR / DV6C.

For some time now, I have had an intermittent problem with irregular engine operation, especially in the transition phases: cold start, start at a red light, resume after slowing down to 30–40 km/h, slight acceleration after a gear change. The engine starts immediately, but it may shake for 1–2 minutes. Then it often runs much better. At stabilized speed, it works very well.

I did several tests with Diagbox and Autel. What is very interesting: when I unplug the air flow meter /MAF, the car works almost perfectly. The jolts and hesitations disappear almost completely. Of course, I then have the normal faults linked to the unplugged MAF, such as P0102 and P0113, and the computer goes into emergency mode with the air flow measured at 0.

When I reconnect the MAF, the engine starts to malfunction again.

I also noticed something suspicious: the large corrugated intake hose, mounted just after the body of the flow meter, moves quite easily on the body of the MAF. There is no metal collar there, and in photos of a compatible VDO/Continental flow meter, the flow meter neck is completely smooth, without an O-ring groove.

So my question is:

On this 1.6 e-HDi / DV6C engine, is it normal that the large intake hose after the MAF is simply fitted without a collar and without a visible O-ring? Should it move easily, especially with a hot engine, or should it be tight on the body of the flow meter?

The hose appears to match PSA reference 9683725080. I wonder if it can be aged/hardened/enlarged and cause an air intake after MAF, which could distort measurements and disrupt EGR/injection management.

Have you ever encountered this problem on DS4 / C4 II / Peugeot 1.6 HDi DV6C?

Thank you in advance for your opinions.

Hello and welcome to the forum.

This is an English language forum so please make your posts in English. Use an on-line translator if necessary.

[microlinkro]

Thanks for the quick response - I posted the same problem on several forums, both in English and French...of course I have texts in both languages ​​but, in a hurry, I reversed them here...

[PaulC5]

It is hard to tell from your photo, but it looks as if the plastic duct is on the inlet of the MAF and not the outlet. On our cars the inlet does not have any clips but the outlet has a jubilee clip. It is possible the MAF is faulty, you need to use a code reader to see what values it is giving and any fault codes. Codes suggesting a faulty MAF could also be a faulty MAP sensor and not the MAF. Could also be an egr valve problem. You really need to do a full diagnostic as just putting it in limp mode disconnecting the MAF will hide lots of possible faults.

[microlinkro]

On the DS4, 1,6 e-HDI, the air filter is in the upper part of the picture, under the windshield - the air flow passes through the filter, enters the MAF and then "goes down" to the turbine (as in the picture). The EGR was changed a few months ago, I don't have any error codes on the engine - I made several measurements on the AIR INTAKE with an AUTEL tester and, when the engine is running poorly, differences appear between MEASURED AIR FLOW and AIR FLOW SETTING... and obviously at these moments problems also appear on the EGR... significant differences between EGR VALVE POSITION and EGR VALVE POSITION REFERENCE VALUE. "Interesting" is the fact that the car was running the same before changing the EGR... that's why I'm going to the MAF - I don't know if the sensor is dirty or out of calibration or there's a problem with the hose being attached to the MAF body - the problems aren't always there, they appear about 3-5% of the time... if I pull on the hose I have the impression that it moves a little easily - if I pull a little harder it comes out of the MAF body

[Paul-R]

When you fitted the new EGR did you use your diagnostic machine to "tell" the car that a new one had been fitted?

[microlinkro]

When you fitted the new EGR did you use your diagnostic machine to "tell" the car that a new one had been fitted?

yes, I did - the car was bought second hand and I've had this problem since I bought it...4 years ago...it's terrible to find a skilled mechanic at Citroen here...everyone "knows" how to change shock absorbers and bushings...if they have to look for a more delicate defect...it's game over...I had to buy the PSA + Diagbox interface and learn from scratch, by myself, what and how to look for a defect...and still I can't solve it...

[iholly01]

When you fitted the new EGR did you use your diagnostic machine to "tell" the car that a new one had been fitted?

yes, I did - the car was bought second hand and I've had this problem since I bought it...4 years ago...it's terrible to find a skilled mechanic at Citroen here...everyone "knows" how to change shock absorbers and bushings...if they have to look for a more delicate defect...it's game over...I had to buy the PSA + Diagbox interface and learn from scratch, by myself, what and how to look for a defect...and still I can't solve it...

We had a similar problem with one of our cars with the DV6C engine a few years back, similar to you it was very intermittent mainly on cold start and would run slightly rough not smooth for a few moments and then it would be fine. The other thing that was noted with it was it sometimes had a slight lag or delay when depressing the accelerator and pulling away from a junction. More annoying than anything else. After looking at a lot of possible causes it was eventually diagnosed to being one of the injectors.

After changing it the problem ceased and has not returned but from memory I am sure the injector had to be coded back to the engine ECU I seem to remember this but as I say it was a while ago.

If you have not done so already I would certainly try and see what the pulse readings are from the injectors and try compare the results when it is running well and then when it is showing the fault you have and see if there is any difference in the pulse timings maybe as they should be the same. If nothing else at least it will rule this out as a possible cause.

As for the Air intake hoses Ours are not a tight fit, slightly tight maybe but still a little movement in them. It maybe that disconnecting the air hoses is just giving the ECU something else to think about as it can't meter the air flow then and that is disguising the real problem ?

Don't know if this will help but may well be with looking at being as you have the diagnostic there to be able to check.

Regards

Ian