YOYO boost

[audinut]

Really weird drove the s2 the other day (been sat for months) had fluctuating boost up to 1.3bar at is highest

car was smoking a little

Cleaned the pcv out as the flame trap was blocked (instant result in a better running vehicle)

Boost now peaking at 1bar ? and have seen it hit 0.8 and 0.9 bar ??

[Rusty]

What's the spec/chip?

Blocked breather shouldn't affect boost really.

[audinut]

its homefry , but after reading some more information I belive I haven't tested it under the right circumstances

[Rusty]

Do a run from 2k rpm in 4th at put your foot hard down and hold it there. Peak boost should be between 3 and 4k and in current temps, something about 1.4-1.5 Bar.

[audinut]

ok was getting 1.4 bar this morning in 3rd and 4th for a bit the next time I tested it only 0.9bar , I have done the test about 5 times now with varying results I either get 0.9 bar max , 1.1bar max or 1.4 bar max (0.9 bar being the most common)

I didn't think I was too bothered until the 1.4bar when she took off ! now I would definitely like to rectify this fault

[Rusty]

VAG Com it. I'd be looking at N75, knock sensors or altitude sensor for electrical and WG for mechanical. Quite a few WG related threads on here at the mo, almost all with lower boost. It's the WG shaft bush BTW, not the diaphragm, as that would result in uncontrolled boost

[audinut]

ok il try and get it on vag com later

as for the mechanical issue , do I just need to strip it down and look for play ?

[audinut]

http://cgi.ebay.co.uk/ws/eBayISAPI.d...ht_1720wt_1241


is this the valve?

[audinut]

Ok its been on vag com and shows no codes (apart from speed sensor)

so shall I start looking at the wastegate?

also what are my options for repair replacement I guess its second hand only

[Rusty]

Take the WG off and have a look at the shaft for play, damage etc. It should move freely without the spring in there but not slop about too much (some slop is reqired to take up the expansion from x00degC temp rise.

That is indeed the N75.