Intake vacuum bellows on start up - video
 

Evening all,

I recorded the bellows on start up to check if they operate normally....however I’m not sure what I’m looking for.

Is the cold start from the video normal operation? They appear to move freely by hand when the engine is off as well. Do they move under throttle as well?

They look slow to me, mine close up instantly on starting.
Maybe you have a vacuum leak or the manifold flaps are not free to move?
They will move back out at fairly high revs - 3000+ IIRC?

That's exactly what they're supposed to do :) They don't move with the throttle, but at a specific rpm (can't remember), controlled by the ECU.

Thanks both. I will ask the wife to record it whilst I give it some revs.

Do you have a video of some that you know operate normally for comparison?