Vacuum Gauge reading help

[Ashwin]

Hi there,

Could someone help me make sense of my vacuum gauge readings.
I teed it off a vacuum hose going to the dash (pic1) however the readings are quite strange from what I 've researched on the net. Have I teed off in a incorrect place ?

a) At idle - the readings appear normal (~22 Hg).
b) Doing a throttle blip - A slight increase by +1-2 Hg before returning to normal. At no point does the needle hit 0 !

c) WOT at 2000rpm (about 15sec) - jumps by another ~ +5-7Hg and appears stuck at that reading after close throttle.

I tried these tests over a period of 1/2 hr , with the engine well warmed up.

The reason I am doing this because recently my exhaust has been giving a funny 'burny' smell /whitish vapor in the mornings. Just enough to sting the eyes in a locked garage.

Also while we are on vacuum gauge could someone please tell me what this steel cap looking thing is on the intake side with a hose going to it ?? (pic2)

thkx

-ash

[Evgeni]

Vacuum should be strongest at idle and part throttle. It should dropp as the throttle plate opens.

WOT@2000rpm?? It should rev higher than this. Restricted exhaust? Does pulling the o2 sensor out of the manifold allow it to rev higher? - just to temporarily unblock the exhaust.

The vacuum unit on the intake is there to control the intake runner valves. As a general rule, the longer the intake runner, the more torque an engine will produce. The shorter the runner, the more power. The valves will use engine vacuum to give you the best of both worlds. Torque at low rpm and power at the top end.

[Ashwin]

Thks,

Ignore the WOT bit . My bad - It shud ve read as rev to 2000rpm for 15 sec.

Anyway - something seems wrong if the vacuum is not dropping close to zero on a throttle blip .

Will try the o2 thing though...