what's this and why is it so noisy?

[d_jay1]

ive located a loud air sound coming from the back of the engine. it's constant and at first i thought i was the fan belt or an old bearing. I think it's the air recycle pipe from the inlet chamber, and when i squeeze it the noise stops, but the revs drop. There doesn't appear to be any cracks on any of the pipes and the clips are all secure, i can't feel any air leaks either, it seems it's making the gushing sound as it goes along this corner pipe, but there's no obstruction in it as far as i can tell and everyhting looks as it should.

any ideas? it really is quite loud!

it's a 1990 scala injection by the way.

here's the pic...

[ianaudia4]

It is the auxiliary air valve.

[stu.gtx]

That's your idle stabilisation valve. You can take them out and soak in WD40 if they stick but when they're faulty the car usually idles at 2k+. The noise you describe sounds like a split hose.

[d_jay1]

ah i see. i'll take a look. might need a soak as my idle does sometimes fluctuate. might be contributing to other problems.

[PeteGLi]

The hose marked in red is from the Auxiliary Air Valve, which assists in cold starting. When you squeeze it with the engine cold and its plug disconnected, the revs should drop. When you squeeze it with the engine hot and the plug connected, there should be no change.

The Idle Stabilisation Valve is the box in the bottom right hand corner of the picture.

[MrP]

I have spare hoses and AAV's if you find any that need re-newing.

Rich.

[d_jay1]

cheers rich , i may well do. it seems like the valve is sticking slightly open. i'm gonna wd40 it and see how that goes. how much do you want just for the valve? the hoses are all fine.

[stu.gtx]

My bad it is indeed the AAV