air pump pulley

[Juz]

i recently had my uim off to replace some vacuum pipes. whilst doing this i also removed all the intake/intercooler piperwork from the front to improve access and clean everything up. after reassembling everything i fired her up and now when i rev the engine gently, as the revs drop back off there\'s a sort of groaning noise coming from the air intakes near the air pump, and when i rev it a little higher the air pump pulley makes a strange noise and even stops spinning briefly!

i\'ve made a short video to explain better...
http://www.juzee.com/files/MVI_0551.avi
(watch the pulley at about 8 seconds and you can see it stop)

please could anybody tell me what has happened?

if i take the air intakes back off i can spin the front off the air pump pulley around freely without the actual pulley/belt moving, and the front also has a little back/forth play in it. is this normal?

thanks...

[turbotoaster]

its meant to stop spinning when you rev it, is the air pump pipe connected to anything?

[ashc]

it has a clutch to disengage above about 3500 rpm iirc, so don\'t worry about it stopping. the noise might be the famous airpump moo which you can hear through the aftermarket airfilters?

[Jono FD3]

correct, the air pump moo as it is called, is basicaly te pump coming back online & drawing air through the filters!

Jono

[Juz]

oh right thanks! just took her for a spin and everything is great. i just never revved it with my ears over the engine bay before so presumed those were new things