My B16 started acting weird. The idle sits at like 2000 RPM . I had to redo the vacuum hoses to pass smog. And now it idles high. When I disconnect the hose on the dashpot diaphram it idles ok. What is the purpose of this dashpot thing?

 

The dashpot should pull in with vacuum, lowering the idle. It's main purpose is to open the throttle plate slightly during start up.

You say you "had to redo the vacuum hoses to pass smog. And now it idles high. "

Recheck your hose routing. You may have one or more connected to the wrong point.

 

double check your setup with this pic:

 

To the right next to the dashpot there is another sensor with a hose coming from it. where does that go to?