What are the symptoms of a bad recirc valve?

[mcandmar]

My AAN is making weird noises, if i hold part throttle coming on boost i can hear a whistleing noise. Suddenly closing the throttle with positive pressure i can hear a fluttering sound. Are these symptoms of a bad recirculating valve?

Thanks,

Mark.

[s2driveruk]

certainly sounds that way....

[newsh]

Yup

[mcandmar]

Perfect, Thanks!

Mark.

[UrS4boy]

By-Pass Valve (BPV) info

Here is some info regarding By-Pass Valves (BPV):

(Look at the hyperlink list at the bottom of the diagram)

Link to AAN engine bay device map including BPV info

[urquattro-island]

hmm

just bought new original BV the other day 5days old, and i am getting fluttering noise allready. Could that be

[mcandmar]

Made good progress today, fitted new plugs and spark boots thanks to Bo and Steve! Car instantly ran better, cured all the miss fires and cutting out problems over 1bar boost. I had got used to driving it under 1bar so its nice to use WOT in anger again!

Replaced the recirculating valve and the strange fluttering noises are gone! It made a massive difference to regular driving, the transition from negative to positive boost is instant, i can even vary the reading on the boost gauge with my right foot which i could never do before. Previously the boost was a bit all or nothing. I was surprised how important this valve is under regular driving conditions. Its a different car now

Cheers guys,

Mark.

[newsh]

When the diaphragm is gone its basically a short circuit round the cold side of the turbo.

[macspring]

Nice one.

Made good progress today, fitted new plugs and spark boots thanks to Bo and Steve! Car instantly ran better, cured all the miss fires and cutting out problems over 1bar boost. I had got used to driving it under 1bar so its nice to use WOT in anger again!

Replaced the recirculating valve and the strange fluttering noises are gone! It made a massive difference to regular driving, the transition from negative to positive boost is instant, i can even vary the reading on the boost gauge with my right foot which i could never do before. Previously the boost was a bit all or nothing. I was surprised how important this valve is under regular driving conditions. Its a different car now

Cheers guys,

Mark.

Mark,

Pleased for you that you've nailed it. What boost does it make on WOT?

Fitted a boost gauge to mine recently, so now all these "x" bar quoted in other threads means more to me now.

Mine makes 1.5 sometimes and at least 1.4 all the time on WOT ?

Kind regards.

[mcandmar]

Interesting, i get a consistent 1.2 bar, occasionally 1.3 bar in 3rd gear. I'm not sure what i should get with a homefry

Can i beg a lend of your test kit again to see if its sprung a leak?

Cheers,

Mark.

[macspring]

Sorry, didn't see this post.

Interesting, i get a consistent 1.2 bar, occasionally 1.3 bar in 3rd gear. I'm not sure what i should get with a homefry

Can i beg a lend of your test kit again to see if its sprung a leak?

Cheers,

Mark.

Yes, no bother.

See my post of a few minutes ago under recent thread regarding Coolant Leak.

Regards.