vacuum reading at intake manifold??

[northern piper]

So I don't know if this is because I'm listening a lot more or what but I'm kinda convinced that I have a vacuum leak on my 2000 3.8. Not DTCs or any real problems I just hear this hiss when the van is running and my head is under the hood. I have a vacuum gauge and can connect somewhere (not too sure where yet) to the intake mana and get a reading. I just don't know what amount of vac the manifold should be pulling. I'm thinking that tartarsauce or wiswind will have a value that a 'normal properly functioning' van should have. Does anyone have any idea?

I have used the hose to the ear trick but can't really pinpoint anything specific.

Thoughts welcomed!

Piper

[busboy4]

HI
on my '96 as I recall, my baseline was about 13"hg.

[tartersauce]

Originally Posted by busboy4

HI
on my '96 as I recall, my baseline was about 13"hg.

A good gauge will show you the correct hg. 13 to 14hg. 16hg the best..
A high mileage engine will show less etc. or leaks...

As you goose the throttle the gauge will drop, when you let off, you should peg the gauge. Every engine will be slightly different due to engine wear. The cut garden hose 3ft or so, works very well in finding leaks. Holding one end to your ear, and the other to each hose, or intake area. The intake does hiss even when its idling normal with no leak, The IAC is pretty loud too...

[wiswind]

As tartersauce says, the IAC will be loud because this is where most of the air entering the intake is flowing through.
The airflow is restricted at idle.....which causes the vaccum.
The higher the vaccum......the louder the sound around the IAC....as the air is moving through there faster.....through a small opening.