Did a compression test. 120psi across the board. Time to dump it off to WBAC I think 
Jaysus that's rough. I don't know the specifications for ED30s, but this is what I found for normal GTIs a while back, I can't find the source of the info though VW says it should be 170psi+ for new engine and it's time for a rebuild under 109 psi
Provided your compression tester isn't faulty, are there any problems otherwise with how the car drives? Have you had any metal flakes in the oil filter?
Ah OK, so I've got 11psi left before rebuild time
It could be the tester so I'll order another one and get a second opinion, as it were.
As for symptoms, it's just completely gutless off boost, and not brilliant in boost either. The throttle pedal just feels like stepping on a bath sponge. Squishy and lifeless. Zero response. It's had a new turbo 1500 miles ago, so it's not that. There were tiny gold coloured flecks at the last oil change, which looked turbo thrust bearing colour to me, hence the turbo swap. But no steel or rod bearing material flakes.
It also struggles to hold the usual 800rpm idle when hot. The longer it idles, the slower it gets, almost down to 600. A few times last week when sat in traffic, the idle dropped down to 400ish, bounced back to 800, then again to 400, and so on. It seems like an injector is dropping out intermittently. The current set are 80K miles old so wouldn't surprise me. I'm loathe to spend £800 on injectors if the compression is that low. Engine is going in the bin if that really is the case, well, the whole car will be!
If I stop the engine and restart it, it's perfectly smooth again like nothing happened! And from cold, it starts on the button and drives absolutely fantastic, almost like a new engine.
If not compression related, it's obviously something electrical but there are never any fault codes when it acts up. Hence why it's had the parts cannon fired at it so many times over the years and believe me, this ungrateful b1tch of an engine has wanted for nothing! There is literally is nothing left to replace, except the block & head!
All 4 plugs are dry and the same colour. It's just unusual to see the whole bank that low on compression, and all at exactly 8.3 bar or something......so maybe it is a sh1tty tester. It's a cheap Gunsons one I bought years ago. But saying that, the same tester measured 14 bar across the board a few years back, so I dunno......it's puzzling.
