strange 5th gear limp mode after TB alignment

[JIMYU]

I'm sorry to post yet another boost thread but here I go anyway because mine is a bit strange

Basically when I plant it in 5th gear my boost often takes a couple of seconds to settle and bounces around a little. ie it normally will spike at 21 psi, fall to 17 then settle at about 19-20 psi. Yesterday I unpluged my MAF briefly to see whether it effected this "boost bounce" but it made no difference and the car ran exactly the same (so I assume the MAF is fine)

anyway this threw up the engine and TC lights so I unplugged the battery last night to clear the fault codes. this morning I did the TB alignment before hitting the road.

Everything seemed fine till I got on the motorway and accelerated pretty hard through the gears (up a hill). By the time I'd hit 5th there was alot of very low, thick fog/mist at the top of the hill and I noticed my boost hit 25psi then I hit 0psi limp mode. I assumed it had overboosted, as it has done before, and is normally fine again after a few seconds.

For the first half of my journey (45 mins) whenever I went above 15psi in 5th I would go back into 0psi limp for a few seconds until I blipped the throttle a few times. The second half of the journey was fine and the car didn't hit higher than 21psi.

The only thing I can think of is the N75 but i can't help but think its related to me disconecting the MAF and battery and TB allignment.

I'm running k03s with all the trimmings btw.

 

[JIMYU]

I've been to the dealers to get the fault codes today...

17963 P1555 035 - value above maximum charge pressure sporadic

16486 P0102 035 - Mass of Volume Air Flow Circ. Low Input sporadic

Obviously this is pointing towards a dead MAF, however I didn't think a shot MAF would cause an overboost?

So I asked SEAT to log the MAF and here's the result:

920 /min
22.6 %
2.5 ms
4.2 g/s

Does this mean anything to you tech guys as I haven't got a clue??

 

[PhilW]

I have no idea what they logged.

Isnt the maf code from when you unplugged it tho?

Sounds like an N75 problem to me tho.

 

[JIMYU]

yeah I've been looking for a cheap n75 thinking it would be that too. I told seat I thought it was the n75 but he said it would throw up a code if it was that...?

I disconnected the battery after I unplugged the MAF so wouldn't that have cleared the MAF code?

 

[truCido]

that log looks like the logged it idling and gave you 1 reading?? lol I'm with a possible N75

 

[JIMYU]

that log looks like they logged it idling and gave you 1 reading?? lol

I think your right mate...the workshop was above the showroom so I know they didn't take it for a test drive. I heard them rev it a bit tho...the pictures on the walls started shaking haha

 

[JIMYU]

Isnt the maf code from when you unplugged it tho?

I disconnected the battery after I unplugged the MAF so wouldn't that have cleared the MAF code?

can anyone confirm whether disconnecting the battery totally removes fault codes?

 

[DaNnY_LaD]

no u can only clear codes via vagcom IIRC

 

[JIMYU]

thanks mate, that confirms what seat told me...I never believe them.

 

[JIMYU]

I told seat I thought it was the n75 but he said it would throw up a code if it was that...?

can anyone confirm this please?

 

[Beaker™]

I'm sure you can clear codes by disconnecting the battery for an amount of time? Also, in my personal experience not everything that starts going wrong will always throw a code so could still be the N75. Can't beleive your dealers attempt at logging your airflow!!!

 

[truCido]

yeah you can clear SOME codes when disconnecting the battery for about 10 mins not all tho and dont ask me which ones

No the N75 wouldnt necessarily throw up a code either