What the hell is this, and what does it do?

[Heat Seeking Missile]

While taking a look at my blower motor today, I found a small vacuum hose that came from behind the carpet in the passenger footwell and came to abrupt end, not connected to anything at all. I then noticed a black plastic "thing" which can only be described as a giant Rolo on the very left hand side of the footwell, that just happened to have the right sized stub coming out the bottom of it. The small vacuum hose was just the right length and diameter to go on to this stub so it fitted on nicely.

Does anyone know what the plastic "Rolo" does and what sort of effect will not having that hose connected will do? I haven't run the engine, just in case it isn't supposed to be connected.

Here are some pictures to try and help.

How it was before:


Now connected:


Mark

[Fat Audi 80]

Altitude sensor for ECU? I think there is something like that down there.

Does the car GO any better now?

Cheers,

Steve.

[jameswkr]

Does the car have Aircon - if so its the recirc valve. I had a boost leak there many moons ago...the altitude sensor is further round nearer the front of the door...

[S2central.net]

Thats the RECIRC valve - stick the pipe on.

There's other threads on it - part of aircon system. Search for vacuum tree if you like.

With that pipe disconnected you'll hear sucky vacuum noises from that pipe.

[jameswkr]

Answers in stereo....

[Heat Seeking Missile]

Steve, I've not tried the car, just in case it wasn't actually supposed to be connected.

The car does have aircon, but its never worked since I've owned, we've never had hot enough weather so I thought it just needed re-gassed. I've not heard any noises out of it though.

Mark

[S2central.net]

You *should* definitely hear noises - I've disconnected one or two by accident when ECU swapping and the noise in the cabin is noticeable... Suggest you check the plumbing further back with help of vacuum tree diagrams to make sure all is well.

Paul

[Heat Seeking Missile]

Should I hear these noises when the aircon is on or off? Or whether the engine is on or off? Maybe I haven't heard them because it was stuffed behind some carpet.

Mark

[Animal Mother]

Should I hear these noises when the aircon is on or off? Or whether the engine is on or off? Maybe I haven't heard them because it was stuffed behind some carpet.

Mark

Engine on, aircon on OR off should produce hissing.

This could be the culprit of your cars lack of power.

[Heat Seeking Missile]

Just been out now to try it. Started the engine, took that little pipe off and couldn't hear a thing. What does the other end connect to?

Mark

[A80Avant]

at the same area the hose connects to a valve and a second hose from that valve to a plastic hose that comes from the engine
the hose sees vaccum and boost and should always be connected to the vaccum reservoir.It is there to operate the recirc of the A/C.Without it the recirc either stays open or closed

[Animal Mother]

Just been out now to try it. Started the engine, took that little pipe off and couldn't hear a thing. What does the other end connect to?

Mark

Somewhere along the Vac tree. I know some connect to the IM.

[Heat Seeking Missile]

I've just had a look at the Vacuum tree. I'm guessing it could be a ropey check valve or a broken vac pipe to the T-piece or IM......******

Mark

[Heat Seeking Missile]

Bit of an update to this thread. I got stuck into the footwell today and the back of the inlet manifold to try and see what the problem was here. After much swearing and numerous skinned knuckles, I think I've made quite a serious mistake.

After being told it was the recirc valve and it should hiss or make a noise with it disconnected as it was, I was confused as to why there was no noise at all coming from it until I realised.......I had to have the A/C on, so I could switch the REC button on, so I gave it a go, with the pipe off again.

Now, being slightly hard of hearing I couldn't really make out any particular noises but for the first time, I could feel vacuum on the end of it, so I stuffed it back on to the stub I originally found, and it all seems ok.

Does this actually mean its sorted now? And that was how I should have checked it?

Mark

[Fat Audi 80]

Sounds like the kiddy to me...