DS3 misfire help please

[Rwoods95]

Hi all,

I have a DS3 Techno (2015) which I believe has the THP 155 engine. I am struggling with a misfire. I have had a re-map done and had the engine walnut blasted by Jamie at 28k miles and it has only gotten worse (now at 30k miles). The misfire only occurs when the engine is idling not when driving and is much more prominent when the engine is cold.

I understand this could be perhaps due to a HPFP issue. Before I go ahead and buy a genuine replacement can anyone advise me as to how to check this is the case? Could the issue also be with the ignition coils? Again how would I check this and where can I buy some genuine replacements? As looking on Ebay there are many different brands all claiming they are genuine and I understand that ensuring genuine ignition coils is important?


Many Thanks!
Richard

[Owd git]

Get yourself an OBD scanner and look at the live fuel pressure data. My idling pressures were all over the place - a new (Mini) HPFP from NEO BROS sorted it

[Rwoods95]

Thanks for your advice.
I changed the Spark plugs today from the NGK Platinum ones (PLZKBR7B8G) to the NGK Iridium ones(ILZKBR7B8G), this seems to have calmed things down significantly, but there may still be a slight misfire I'm not sure if its my imagination. Do you know what the pressures should be or will it be obvious that they are not stable?
I understand that the mini R56 HPFP's are cheaper than the Citroen ones but still the same part, if I notice any differences in the pressures at idle I'll be sure to check out NEO BROS.

[Chris_Blue]

Is it THP Death rattle related ? (A Mini term)

Mine hesitated for a few days at one stage, then gave up the ghost

It was the HPFP in the end which was replaced, but they swapped and changed injectors, coil pack, plugs etc etc

Death rattle is usually n first start up worst, then fails to go away

[Rwoods95]

I am not sure it is the "Death rattle". It is more obvious when the engine is cold however once warmed up it is hardly noticeable. Also they misfire seems to only occur during idle I am yet to experience it when accelerating (fingers crossed).
I am interested in if anyone has any figures I should expect for testing the HPFP using an OBD scanner to ensure that this is the part at fault so that I do not end up spending around ?400 on the wrong part.
Also if anyone could suggest where to find the best (or genuine) ignition coils as there are many different brands on Ebay claiming to be original? As I have seen in a previous post Jamie recommended to buy Delphi but only with the metal cover?

[Owd git]

Use the search function on this forum - plenty of useful info including THIS

[Rwoods95]

Thanks for your reply. So when monitoring using a cheap bluetooth OBD2 port and the torque pro app, when idling the fuel rail pressure is around 680-720 psi (46-49 bar) around what your linked post suggested it should be (45-52 bar). As the misfire is only noticeable during idle would this indicate it is not the HPFP? as I said I don't want to spend another ?400 on this problem for it not to be fixed

[Owd git]

If you're not seeing any fault codes then I suggest that you give Jamie a call