407 hdi 2.7 fuel pressure and injector issues

[407]

I've been fixing some issues with the Hdi including replacing the high pressure diesel pump, which fixed a knocking / cavitation issue and also an overpressure issue as diesel was leaking from the rear 3 injector pipes (never leaked from them before) - no metal or other grindings found in the diesel filter etc

Prior to the pump issue all injectors were within spec and no codes thrown up re injectors.

Now the car runs okay at over 2000 rpm / no depollution issues re particle filter / no smoke but has "misfire" issue at idle / sometimes will stall on take off.

Diag global test seems to reports inconsistent injector correction readings (unless I am reading these wrong)

P0191 fuel pressure signal - (poor contact) - not sure what to do this one one as I tested the wiring and it is fine / contacts are clean - I installed a new fuel pressure sensor (1570H4) but no change

P1164 fuel pressure signal (pressure coherence) - seems to be an issue at idle based on the pic attached
eg - @ 640 rpm it is asking for 321 bar but only getting 259 bar
- @ 2944 rpm it is asking for 619 bar and getting 619 bar

P0263 (cylinder 1 / injector 1) - 41% injector correction time outside tolerance

P0272 (cylinder 4 / injector 2) -100% - this makes no sense as 100% means it should be okay

P0275 (cylinder 5 / injector 4) - 50% or 75% - not sure why different reports have different % noting the ECU says it only reports if is it is below 60% and over 140%

P0278 (cylinder 6 / injector 6) - 40% -below 60% so an issue for the ECU

Looking at other readings (see pics attached), I'm not sure why the ECU did not flag some of them eg Cylinder 2 / injector 3 - 159%, Cylinder 3 / injector 5 - 40%

It seems if I replace the front 3 injectors (being 2, 4 and 6) I might fix the issues (other than the low pressure at idle)

Any comments / suggestion welcome

[mickthemaverick]

Realising how old this post is I wondered if you have resolved it and would like to share the information for other members benefit?

[407]

Hi Mick

Issue got resolve but can't say it was a specific fix.

I changed the diesel filter (again) and went for a long freeway drive (italian tune up)

20 mins into the drive I noticed white smoke behind me and pulled over and found the front middle injector loose and leaking big time at the top at the piezo nut - it somehow managed to unscrew itself. Tightened it up and drove back home

Even since then its all been working fine - turbo boost even gets to 1.5 bar on big hills and have never seen the particle filter blocked message (used to happen all the time before)

I can only assume the freeway drive cleared whatever was not working (although I did that a few times before but it ran badly)

That said, today when it seems the water pump seized and took the belt out - sigh