Dreaded black smoke

[EthelredS]

Hi everyone - I’ve just joined the forum and this is my first post.
We’ve got a 2011 Picasso 1.6hdi Exclusive, purchased two years ago with 25k on the clock, it now has 41k. Until we purchased, the car had been in the same family from new with regular services and maintenance and full MOT pass history.
The problem we have now is black smoke on acceleration and idling with no fault codes or dash warnings and brilliant performance.
Here is a run down of what’s been done recently. The report from our local garage - “ Carried out fault codes scan. No fault codes present. Carried out smoke intake test and no leak found. Fitted known good mass air flow meter and Map sensor. Fault still present. Refitted original parts. Replaced air filter. Removed EGR valve and tested - all working correctly. Removed DPF lower section and inspected for holes or damage - DPF very dirty but intact. Recommend vehicle is taken to Citroen for further diagnosis”
Comments from Citroen main dealer “ Black smoke coming out but no faults on dash or live faults. Carried out diagnostic and found fault p0272 present. (Injector 4). Carried out engine ecu download and rest auto adaptive. Next step if doesn’t improve is removal and test of injectors” When we collected the car we were told that the fault code was historic and not present after resetting.
Still had black smoke and decided to go ahead and get the no 4 injector replaced. Our local garage did this using a refurbished one. Still had black smoke. Realised the fuel filter was due to be replaced having been done at 11k miles. That was done yesterday. Still have black smoke.
I keep thinking that if half of the DPF was very dirty then the other half will be too. (The half of the DPF that was removed was cleaned out). We’ve never had any warning lights come up and the only code is the historic injector one. At the moment we’re undecided on whether to get the rest of the injectors replaced or the DPF replaced.
I would love to know your thoughts. I must emphasise that there is no issue with performance - proper little pocket rocket.
We were planning on driving up to Nottingham from Somerset this weekend to catch up with family but that isn’t happening now
Many apologies for the long post, and congratulations if you’ve read this far.

[PaulC5]

Your local garage will know this but Citroen tend to number the engine cylinders from the gear box end so what you think is no.1 cylinder at the timing belt end is actually no.4 cylinder. Worth a check in case the garage replaced no.1 injector at the gear box end and not no.4 at the timing belt end.

[EthelredS]

Many thanks - I’ll check this out

[EthelredS]

Your local garage will know this but Citroen tend to number the engine cylinders from the gear box end so what you think is no.1 cylinder at the timing belt end is actually no.4 cylinder. Worth a check in case the garage replaced no.1 injector at the gear box end and not no.4 at the timing belt end.

Just checked and the new injector is at the timing belt end

[malc4]

Has it been smoke tested for leaks? eg https://www.youtube.com/watch?v=Qagn0FmMZ5w
edit it appears so - missed that in OP;)
dpf pressure data would be useful to gauge integrity of dpf..
ps i get occasional contribution balance codes but no black smoke and tailpipe clean;)

[EthelredS]

On the cusp of replacing fuel injectors, it turned out to be a damaged DPF. All nicely smoke free now

[wurlycorner]

Glad to hear this is resolved for you.