2007 C3 Pluriel 1.4HDi clattety clacking!!!

[AllanA]

Hello all

In this post I'm looking for a knowledgeable second opinion to my own diagnosis, which I won't describe here at the moment. I've been connected with the automotive industry for 50+years so know a bit beyond the basics of diagnostics but this issue on my wifes car has me really stumped. Been trying to sort it for some weeks and I've even conjured up a few new unmentionable expletives!!

Long story cut short is as follows. The car is 2007, owned from new and has 61000 miles registered. In 2021 I felt it was time for a timing belt change and as I had a lot of other projects going on at the time I put the car in to a local garage with a good reputation for a cambelt, idler, tensioner and water pump replacement. Job finished and the car ran well for about 4/5 months.

Then it started to cut out occasionally whilst driving and sometimes it would start and immediately cut out. After a few minutes it would start again and drive for some days or even weeks. Gradually this got more frequent so I decided to investigate it myself.

Out came Lexia and it showed many speed errors in the log - mainly PO339, so an inconsistent camsheft/crankshaft timing. First thing I checked after removing the timing covers was that the timing belt was still intact with no missing teeth. Next was the a visual inspection of the reluctor ring. BINGO! quite a few of the magneic sections on the outer circumference of the reluctor ring were gone. I then inspected the crank sensor and found that there were marks on it associated with rubbing on the reluctor ring. So my analysis was that when the cambelt job had been done some months previously the sensor had been fitted with insufficient air gap between it and the reluctor ring resulting in rubbing and damage to the reluctor ring magnets.

I subsequently found when fitting a new reluctor ring and crank sensor that indeed there was sufficient tolerance in the sensor fixing point to allow it to rub on the ring. I fitted the new sensor with a 2mm air gap.

Also since it was dismantled to replace the reluctor ring I fitted a new cambelt. Crank locked, camshaft locked and fuel pump locked. Turned six revs clockwise by hand, then again and again to be sure. All lined up and lock pins could be inserted in their relevant positions.

I also noticed that when priming the fuel system there was air in the system so replaced the fuel filter and the fuel lines which came as a fuel line harness.

Now my real issue. Started the engine and it idles real sweet and smooth at 768 rpm. Gentle increase in rervs and at 900/920 prm the is a sudden clack/clack/clack noise and the engine misfires. Release the acelerator and it's back to very smooth idling. Sound at the exhaust is completely normal with no indication of misfire.

I removed the timing covers and the crank/cam/fuel pump holes all align and lock in place correctly. So it's not a timing belt issue!

Also run the engine briefly with no serpentine belt. No change in noise but rules out TVD on crank pulley.

Lexia shows fault code PO104 - Flow meter fault. This apparently relates to the Mass Air Flow sensor! What??
Lexia also shows PO238 - Turbo Pressure fault!!
Lexia also shows PO 339 engine speed (crank/cam) mismatch. Which I think is down to the clack/clack and misfire occurance.

So, I'm at a loss. I'm thinking possibly a fuel pressure issue caused by air in the high pressure system but with the new low pressure lines and no sign of air in that low pressure system I can't fathom how that could be.

All informed suggestions are welcome and thanks for taking the time to read this lengthy post :)

[AllanA]

Links to two videos I made today. Clear exhaust sound and one with engine running at idle and gently increasing revs to 920ish when the noise starts then returns to normal when back at idle speed

[AllanA]

[AllanA]

OK, back to work on this engine.

Two things I'm considering doing today. Firstly, with the engine off, place some absorbant paper/cloth adjacent to all 4 injectors loosen the hp injector pipes and crank the engine several times to purge any air that may be in the high pressure common rain. Unlikely but it's worth a shot.

Secondly, I understand from many technicians that the high pressure fuel pump doesn't need to be timed to the engine. So I ask why the pump lock off facility?

When changing a timing belt the crankshaft, camshaft and fuel pump need locking pins inserted. However if one were to change the fuel pump, the new pump would need to be set with the lock off hole lined up so a lock pin can be inserted. Fit a new belt and it's suggested to rotate the crank six times clockwise and check all lock pins line up.

So each time the crank has turned twice , the camshaft has turned once but the puel pump does not line up. A further two crank turns and the fuel pump still does not line up. It's only after the next two crank turns that the pump lines up again. So each two turns of the crankshaft puts the alignment hole in the pump pulley either at top position, 120 degree or 240 degree position. How does that effect sensor signals to the ECU?

Now I'm wondering if I were to loosen the timing belt and rotate the pump pulley 360 degrees or 720 degrees, effectively altering the positions of the pump location hole each two turns of the crankshaft, would that have any effect on the cause of this engine issue?

Any thoughts please!

[wheeler]

You are correct that the pump is not timed however I believe that it is set for internal balancing reasons.
As for slackening the injector pipes, this is a big no, the pressures involved are ridiculously high & could cause some serious damage or injuries.
If there was air in there i would think it would purge out within a couple of minutes of running the engine.

[Doo]

The MAF on a diesel is there purely to operate the EGR valve so it could be an issue with the MAF and/or the EGR.

However, I suspect your engine may have an issue with the cam sensor. If this is faulty, the engine will misfire. It tells the ECU the position of the camshaft in relation to the position of the crankshaft which allows a pinpoint firing order. If as I suspect, the sensor is on its way out, the engine will not start or if running, misfire. If this happens, the airflow is interrupted and the turbo pressure will drop momentarily.

I had a similar misfire issue with bad injectors, crackle, pink & plop. Not good.

[AllanA]

Happy to report that this issue is now resolved!

I checked and checked and checked again and the only thing that kept flagging up in my mind was that there must be a problem with the new reluctor ring I'd fitted.

So splashing the cash I ordered a new genuine one from Citroen. It arrived yesterday and today I fitted it and reassembled all components. Key in and engine immediately started, nice smoth idle and clean through the rev range.

So the after market reluctor ring was faulty in that it was sending incorrect signals to the ecu.

I bought the after market reluctor ring from an online auto parts seller. It is a Metzger brand, apparently of German origin.

So, a word of warning to anybody with a similar issue requiring a new reluctor ring, buy a genuine OEM part for this critical engine timing job.

[AllanA]

Happy to report that following my complaint to the seller, I have now received a full refund for the reluctor ring.

Also realised in my post above I made an error. The reluctor ring brand was Maxgear and not Metzger

[Jay-Bruce]

Glad this ended well