vacuum hose on throttle body, what is it for?

[john wyatt]

At front end of the throttle body, there are 2 silicone hoses which join into a 4 way piece, one end of the silicone hose disappears over the bell housing and other is blanked off, can someone tell me what it is for? Thanks Jonny

[Tanguero]

Purge line for the carbon canister that is located next to the fuel filter in the rear passenger side wheel arch.

[john wyatt]

Thanks Tanguero what does the carbon canister do?

[N7GTX]

Instead of venting petrol fumes to the atmosphere like old cars used to, the fumes are stored in the canister until the ECU opens the valve and they are then drawn into the engine where they are burnt. Normally this only happens when the car is moving and not stuck at lights so as to keep pollution to a minimum.

[john wyatt]

Thanks for that, strange things to work on, being such a mix of old and new technology!

[MackemPete]

How strange is that. I was just about to ask this question myself. The 4 way piece you are talking about is it just on top of the air con pump?

Due to the proximity of the exhaust and the hose that runs to the rear of the car, I think I'll wrap mine in heat protection. Even if its only fumes id prefer it not to perish and vent next to the manifold.