Photonic

Seriously..

It should be simple to find out..but the only info I Can find is how to "rebuild rotaries" which is useful..

But that leads me to conclude the ports arent actuated at all...and that exhaust flow and intake flow are directly caused by the rotor moving over the ports, sealing them, or opening them to push/draw in air/fuel.

So what the hell does the air pump do..

RotaryRocket88

iTrader: (7)

Your post is all over the place, so I'll take a stab at it.

The air pump is also known as a smog pump. It pumps air into the exhaust / cats for emissions.

Did you have some other question about auxilliary port actuation? On S5 NAs, the air pump is tapped into for that, but on all other FCs it's strictly emissions related. Aux. port actuation on S4 NAs is done by exhaust pressure through the split air pipe.

fast2g

the air pump opens the auxiliary port which allow more air when the engines rpms are about 3500.. if you take it out and open the aux port it suposed to run bad at low rpms but i did it
to my fc and i did not notice a difference.

Photonic

I see. so its not totally critical.
Cool ^_^.

still having troubles starting the car so I have nothing to do in the mean time but figure out how everything works..

Photonic

Ok im getting pissed at the time it takes new threads to appear..Im out here working and I cant ask questions..Ive never had a car forum like this...

I need help with compression testing! never done it before, I screwed the tester into the trailing sparkplug hole...cranked it over..the needle does not move at ALL

*shrug* Is there something I need to know? Theres a little mechanical button on the side of the gauge..does it need to be held down or something??

RotaryRocket88

iTrader: (7)

There may be some delay time for posts in the newbie sections to get approved. You can post in the 2nd gen tech section with no delay. Do some searches for compression testing. Some testers require you to remove the schraeder valve, and pressing the bleed button should give you the compression per face (~30-35psi) instead of the combined value. The throttle plates should also be open during the test.

Photonic

Well All I had was the autozone compression tester that I rented.

The shraeder valve is that little "pin thing" right? it was just a hose and that valve was fixed to it so I couldnt remove it..and it plugged into a gauge *shrug*.