Vacuum?

[irishsetter]

Where is the vacuum generated from?

[Threshld1]

the cylinders moving creating a low pressure...

[Subtle]

On each of its cycles, the piston is compressing,then transmitting chemical energy into kinetic energy and in between it sucks.

[Threshld1]

http://auto.howstuffworks.com/engine1.htm

[magicmike]

to be more specific, in the opposite stroke than the combustion stroke. when the piston goes down it sucks in air. On a turbo car you still have a vacume until the turbo creates more boost than the force of the vacume that the engine is creating by itself. At that point you have air being forced into the cylinder so technically the engine looses all vacume. I'm sure someone will chime in with a very technical description. I'm definately over simplifying it just to have it make some sense.

[irishsetter]

I guess what I am asking is the vacuum is generated in the engine and I know that but for all the vacuum lines and sensors it is from the intake manifold. so if i have a vacuum of 10" at the manifold then would that mean that problem is from the engine? Maybe the timing? If it was the timing then how do i set it?

[vrg3]

The vacuum is generated by an air pump (the engine) sucking air through a restriction (the throttle).

Low vacuum generally means the pump is not moving enough air, the restriction is not small enough, or there is a leak allowing extra air in.

I seem to remember you having trouble with your idle vacuum before... Why not continue that thread to figure out what's wrong? Here I feel like asking a bunch of questions that I think I may have already asked.

[irishsetter]

Ok thanks. I was just trying to start back with the basics to see what I am missing.