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Injectors and EGR mystery in Lexia/Diagbox - Rough idle and low power at low RPM's

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Sat Jun 10 2017, 07:43am
Member No: #48330
Joined: May 10 2017
Location: Belfast
Yes rusky, that's the one. As far as I know (and I don't know very much ) the glowplugs also operate as part of the EGR system hence the connection. I now have my EGR blanked off, it hasn't lit the EML as feared so I may leave it blanked and see how it fares during the MOT. I've been told its not a failure point... we'll find out soon as it expires next week!
Sat Jun 10 2017, 07:52am
Member No: #48330
Joined: May 10 2017
Location: Belfast
Gmerry, yep its now come to that stage where all the cheap fixes and tests have been tried and failed so it's basically down to the items on your list (most of which I was praying to avoid)!

I've found it hard locating a good local technician, I have one chap I'll be calling again on Monday morning... hopefully he can fit me in soon and come up with a definitive cause... and then fix it!

I'll keep you posted, fingers crossed - Mervyn.
Sat Jul 22 2017, 03:18pm
Member No: #48330
Joined: May 10 2017
Location: Belfast
I have now eventually had this issue resolved.

Turns out it was a badly burnt valve on clyinder No.1 The piston crown on that cylinder was also partially melted/burnt away!

Turns out that all the diagnostics were of no use whatsoever, the injector in cylinder No.2 is still showing as "invalid value" although this does not appear to affect the cars running, it now idles smoothly and drives well... still a bit clattery mind although this quitens down once warmed up... seems these engines just aren't very refined!

Thanks for all the help and support - Mervyn.
Sun Jul 23 2017, 12:02pm
Member No: #11625
Joined: Nov 30 2009
Location: aberdeen
Hi Mervyn, there's a certain chicken and egg here:

Basically the burnt valve / melted piston would not have happened in the first place if the leaking injector seat / faulty injector had been attended to completely and promptly.

Having owned DV6ted4 and DV6C engined vehicles from new, I can assure you that they are very refined and capable - and should remain so if properly maintained.

Good that you have got to the bottom of the running problems. Presumably the leakdown tests indicated the valveseat / piston problems

1 User said Thank You to gmerry for this Post :
 Mervyn44 (25 Jul 2017 : 14:55)
Tue Jul 25 2017, 03:51pm
Member No: #48330
Joined: May 10 2017
Location: Belfast
Hi gmerry,

I bought this car knowing it had issues. In hindsight, the previous owner likely reasoned that the cause was the Injector on No.1 cylinder and replaced it (to no avail as internal engine damage had already been done). Hence his decision to sell!

When I got the car the injectors were no longer the problem (despite the goose chase initiated by the peculiar readings in Diagbox for injector No.2)

Basically, no amount of injector work would have gotten me back on the road (which as you know, I suspected). Turned out that I had a burnt valve and melted piston.

I guess if there is a lesson to be learned here it is... knowing a car's history is very important! It is a lesson I have learned to my cost.

Having said all this... now that I have begun driving the car another problem has arisen ( P0234 - Turbo overboost) but I should maybe post that issue in another thread.
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