Ok so I had a look at the beast today.
The first thing I did, was tighten up the downpipe to turbo joint. I remember when the car drove off the truck, there was a massive exhaust blow. I thought "That won't be helping things". Looking underneath, the nuts holding on the downpipe were all undone several turns, so the downpipe was sat about 0.5cm from the flange.
I nipped up the nuts, and thought "that will sound better".
I started her up, and heard this:
https://youtu.be/ds5FDkRa-BoYes, a very loud, strange, unpleasant noise!
So I loosened the downpipe again, and the noise went away.
So there's clearly a massive issue (blockage) with the exhaust / cat / DPF? My question is, why!
It's led me to think - with the engine also unning on around 2.5 cylinders, has something (the turbo?) massively let go, and jammed the exhaust / hit the valve seats with shrapnel?
Or, maybe the car has been ran for some time with a misfire, which has slowly blocked the DPF?
When I removed the exhaust, (much to the neighbours delight I'm sure) it ran like this:
https://youtu.be/jC-bxxr_lNIThe nasty noise gone, but still misfiring. You can also see in the video, there's no change when no2 and 4 injector plugs are removed.
I've changed the No4 for a known good injector, but the issue remains the same.
I'm guessing next stage is a compression test, and maybe take the pipe off the turbo and see if I can see if It's in one peice!
Any advice gratefully received.
No fault codes stored at all in the Engine ECU. Although interestingly, with my tool that cannot be named, it connects, identifies the VIN etc, and will read and reset codes, but all of the live-data and programming options don't work. Wonder if it's a version issue. At the moment, I don't know how much it's been played around with, and if the correct injectors are coded to the ECU.
It looks like the rocker cover has been off not that long ago, so not sure I buy the guys story about breaking down and the AA coming out, and not attempting any sort of fix first. That said he's not a trader - it's been in his name for 5 years or so.
Any tips gratefully received on where to go from here.