I want to check the operation of my engine's resonance flap by energizing it with a vacuum pump, but of course you can't see or feel its linkage when the engine is in the car.

Can anyone think of a way, without taking it for a drive and revving it past 5K?

... Gregg

 

Try THIS link for a suggestion

 

I tried applying vacuum to the hose, and the valve held it without trouble for quite a while. So, at least I know there are no leaks ... although I don't know if the valve is actually operating (ie, not seized).

To be sure, next time I have the inlet manifold apart, I'll have to check the valve physically after applying vacuum. I doubt that operating the valve at low engine speeds with the car stationary will prove much.


Anyhow, I then took it out for a drive, and I don't know if it was my imagination, but revs seemed to build more smoothly after 5,500 rpm. My recollection was of a more sudden power delivery after 5,000.

Any comments?
... Gregg