I have a 2008 gti mk5 that I'm trying to tune. I've been experiencing some timing pull and my lambda o2 sensor is not reaching specified (leaning out).
My mods are:
New TBO k04 turbo
New s3 injectors (06F906036F)
New RS4 fuel pressure relief valve
New Integrated engineering HPFP upgrade kit
forged JE pistons and Forged integrated engineering rods
r8 coils with bk7RE gapped at .24"
3" milltek downpipe, 2.5 catback
Forge front mount
Cold air intake kit with k&n filter
Boost around 20-25 PSI
Ran a scan with VCDS and there's no engine codes or bad sensors. Been trying to tune with a local tuner and we added a "safe" tune with a Lambda bank specified value of .84 before going to the dyno. After 4k rpm's the car starts to lean out and pull timing. Tuner suggested to replace the LPFP with an OE unit which I did (brand new continental LPFP -1K0919051DB). All maintenance has been done by myself which includes a new MANN 6.6 bar fuel filter, timing belt kit, all fluids replaced, etc. What I'm I missing here? What can cause the engine to pull timing and not reach specified lambda values, specially if the actual fuel pressure meets and even exceeds specified.
Here's an image of my simplified log.
