Rough Idle / Misfires after Timing Chain Replacement

[Tony48]

UPDATE: See comment below. Car is running fine now (12/29).

Hello everyone, I've been diagnosing a problem with my GTI all day and haven't had any luck. This is going to be a long post so first some background:

A few days ago I did a full timing chain service. It wasn't too bad since I was well prepared and followed the service manual to a tee. New camshaft chain/tensioner/rails and new balancer shaft chain/tensioner/rails. Cam bridge screen was intact so I left it as-is. Also replaced the diverter valve while I was there. Put everything back together and the engine turned over and ran smoothly (whew!). This was late at night so my test drive was delayed until the next morning. I drove around for about 15mins through varying RPM and boost levels. Car felt better than it ever had before. I was ecstatic.

Next time I drove the car was yesterday night and before I can even get out of the driveway I get a flashing CEL and super lumpy running motor. Break out the VAGCOM cable and I have p0300, p0301, p0302, p0303, p0304 codes for misfires in all 4 cylinders and random/multiple misfires.

I figure it's a boost or vacuum leak from something i bumped loose so I go back and check everything. I pull the plugs and coilpacks and run a compression test. 175-180 psi across all cylinders -- fine there. Switch my diverter valve back to the old one to rule that out.

I continue running the car trying to get it to throw more codes. Idle is a little rough and when I start moving (putting the engine under load) engine gets super lumpy within a few seconds (boost gauge flicking around from 0psi to a few in-Hg vacuum) and feels like a vacuum leak. It only lasts a few seconds before it goes away but it always comes back when I put the engine under load. After a dozen or so of these bucking sessions I finally get it to throw a code. More misfire codes and P052A:

001322 - Camshaft Adj. Bank 1 Intake
P052A - 000 - Cold-Start Timing not Reached
Freeze Frame:
Fault Status: 01100000
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 171065 km
Time Indication: 0
Date: 2014.14.02
Time: 18:02:32

Freeze Frame:
RPM: 1005 /min
Load: 32.1 %
Speed: 0.0 km/h
Temperature: 49.0°C
Temperature: 27.0°C
Absolute Pres.: 1020.0 mbar
Voltage: 14.097 V

Now I'm thinking it's timing related so I pull the cam cover and cam bridge back off to check timing. They're perfectly fine, just where they should be (factory spec 124-126mm between intake and exhaust cam markings). I'm stumped. Perhaps it's an issue with the camshaft adjustment system (cam bridge, n205 valve, camshaft adjuster magnet) or a faulty PCV? I tried disconnecting the PCV connection at the intake manifold and plugging the manifold but that didn't help. Anything else I can do to test the PCV? I'm going to put it all back together, run the car, and log block 091 to check my intake timing. If it's pegged at a certain angle despite what the ECU requests then I'll replace the n205 valve. Any way I can test the n205 valve or camshaft adjuster magnet now while they're off the car?

If you managed to read all of that kudos and thank you! I really hope I can get this resolved soon! I've added some pictures of the timing chain job for your visual stimulation!

IMG_20171227_210936 by Tony G, on Flickr
IMG_20171224_154305 by Tony G, on Flickr

All of the old pieces:
IMG_20171226_120127 by Tony G, on Flickr

The fresh system with new chains/tensioners/guides:
IMG_20171225_142441 by Tony G, on Flickr

[Tony48]

UPDATE: The car is now running just fine. Not sure exactly what the problem was but everything ran perfectly after I cleaned & reassembled the camshaft bridge, N205 valve, camshaft cover, and camshaft adjuster magnet. My best guess is that the N205 valve was stuck in an incorrect position and retarding timing. Unfortunately I did not log block 091 (intake cam timing) before tearing the system apart, but after the rebuild it is logging correctly. Hopefully this helps someone out in the future.

[Dans GTI]

Could it be the cam magnet on its way out?

[Tony48]

Originally Posted by Dans GTI

Could it be the cam magnet on its way out?

Potentially, but for now it's working. If I start getting the same symptoms I'll probably replace the cam magnet and/or N205 valve.