Citroen c5 2012

[Pepe autotechnics]

Hi I have a Citroen c5 1.6 hdi 2012 and I have low boost pressure on hard acceleration the turbo is almost new 1 year ago and I have tested the vacuum pipes with miti vac and hold pressure and I have tried a new solenoid valve but only get 70% ocr in parameters on idle and 50% ocr on hard acceleration I suspect it could be a ecu problem do you have any ideas!!

[Paul-R]

Have you run a diagnostic session with a high end diagnostic machine, preferably Diagbox?

If you run a session make a note of all the error codes (DTCs), clear them and then see what is left after clearing. Also see what DTCs come back after taking the car for a short run.

[Pepe autotechnics]

Im using diagbox, it has only 1 error code preheating fault possible glow plugs or relay but nothing else, preheating fault wont cause my low boost; I done an injector leak off test on all the injectors and they are all a bit on the high side and every now and then I get a bit of miss fire from engine and occasionally runs very lumpy!! But no fault recorded on diagbox!!

[Pepe autotechnics]

Do you think the injectors could be causing my low boost??

[Paul-R]

Possibly. What exactly is the error code and description?

[Pepe autotechnics]

I don’t have any error codes for injectors, only have error code for preheating which is the glow plugs, that won’t cause my low boost, but injectors leak off test was quite high and when I took injectors out cyl1&4 where very wet inside cylinder head on crown of piston, also car runs very lumpy like it’s miss firing!!

[Pepe autotechnics]

Ok update on Citroen c5, I found blocked particulate-dpf filters which was stopping the turbo from spooling properly, caused by the leaking injectors over time blocked filters, I have replaced particulate-dpf filters and new injectors and relearned filters and injectors and the car now drives as should do, has correct amount of turbo boost now and drives beautifully!!