I apologize for posting about my Eos in a Golf forum but I've hit a wall with this issue and it has the exact same engine as a MK5 GTI, so I'm hoping there's some people here that might be able to help.
I've recently rebuilt my cars engine (EA113 BWA) and surprisingly, everything went pretty well. Once it was all back together it started, ran and after getting it checked out by my mechanic, it was certifiably running smoothly. All was well until after less than 10km of driving it cut out and wouldn't start. So here's the story so far:
Car cut out, wouldn't restart, replaced battery but didn't fix, towed to mechanic
Sat for a few days, car ran normally for mechanic, they assumed fuel line just had air bubble, took it home
Cut out on drive home (after approx. 5km), wouldn't start but got code P2293
Had cracked N276 + the code so replaced HPFP and it started
Ran for longer (10km or so) but cut out again on drive home
P2293 code gone but new code P310B, so replaced G410 sensor, car started and ran
Got even further this time (about 20km) but cut out once again
P310B came back so replaced fuel tank pump and fuel pump control module
This time didn't run. P310B is gone but still wont start.
Previously it had occasionally started properly for 3-4 seconds and then died, but this now rarely happens (still sometimes though).
When it starts it runs perfectly, so I doubt any timing issues.
Only other issue is once or twice when actually driving and accelerating, it jerked really bad like it had a terrible gear change, but I've heard a fuel cut can cause this type of thing too.
Known good parts:
Fuel Tank Pump - Replaced (tested at 6.something bar with pressure gauge so fuel filter also fine)
Fuel Pump Control Module - Replaced
G410 Low Pressure Fuel Sensor - Replaced
High Pressure Fuel Pump (inc. N276 valve) - Replaced
HPFP Cam Follower - Replaced (looked fine before replacing)
Battery - Replaced (and voltage tested good)
Spark Plugs - Replaced
Coil Packs - Replaced
Only other reported code was something about the PCV system/purge valve but I can't remember, I didn't write it down as I assumed it was just due to messing around with the PCV hoses when testing things. Could be a clue but I'm very unsure about it. Could a vacuum leak cause an issue like this?
I'm pretty much at the end of my diagnostic ability, the car is sitting on the side of the road 30min away from my house so I'll probably have to get it towed soon. If anyone has an idea for other things I should test/replace before that happens then please let me know, I'm not strapped for cash by any means but the time and money I've spent on this is really starting to get to me, I put so much effort into rebuilding the engine and I just want it to drive again. Any help is very appreciated.