I just bought a vacuum tester, and hooked it up to my B16 to find I have about 26 in hg of vacuum at idle. The testing guide says it should be between 18 and 22 in hg, but I can't find any information to describe what high vacuum indicates!

Does anyone else get a similar vacuum reading from their B-Series? Does anyone know what 26 in hg means? The needle was steady within 1/2 in hg..

 

Anyone?

 

No one has a clue what high vacuum indicates?

 

Is the engine running rough or something? I'd be more concerned with a low vacuum reading than a high one. Is it reading 26" with the engine fully warmed up and the idle around 700rpm? Or just when you start the car cold and the idle is raised for that condition? What does it pull on decel?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">Is the engine running rough or something? I'd be more concerned with a low vacuum reading than a high one. Is it reading 26" with the engine fully warmed up and the idle around 700rpm? Or just when you start the car cold and the idle is raised for that condition? What does it pull on decel?</TD></TR></TABLE>

Hey! It's my favorite electrical engineer!

It's at 26" hg with the car fully warm and idling between 750-800. If I blip the throttle the needle exceeds the measurements on the gauge (31" hg+)

When you say on decel, do you mean I should go take it for a drive or just open the throttle and let it fall?

 

higher vacuum could be an indicator of bigger cams

or do I have that backwards?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondapwr &raquo;</TD></TR><TR><TD CLASS="quote">

Hey! It's my favorite electrical engineer!

It's at 26" hg with the car fully warm and idling between 750-800. If I blip the throttle the needle exceeds the measurements on the gauge (31" hg+)

When you say on decel, do you mean I should go take it for a drive or just open the throttle and let it fall?</TD></TR></TABLE>

The decel vacuum is probably not something that you can do with the equipment that you have. What he is talking about is having something like a boost guage or a guage that you can have in the car and take a drive. You would give it some gas then let off with it still in gear and see what the vacuum goes too. I can't give you much help beacause my Hg boost guage is off a little I think and my e01 does not run in Hg. For what it is worth though my Hg guage reads 20 on decel and about 17-18 at idle.

 

How's it going man - been awhile certainly.

Did you just recently do a timing belt change? Have you checked timing with a timing light?

Did the engine begin to run differently - that's why you bought this gauge?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by The_Head &raquo;</TD></TR><TR><TD CLASS="quote">higher vacuum could be an indicator of bigger cams

or do I have that backwards?</TD></TR></TABLE>

Big cams (cams that have some decent overlap) usually lower vacuum though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">Did you just recently do a timing belt change? Have you checked timing with a timing light? Did the engine begin to run differently - that's why you bought this gauge?
Big cams (cams that have some decent overlap) usually lower vacuum though.</TD></TR></TABLE>

I have stock SiR II cams in my B16.

I installed some cam gears a long time ago and set INT+4/EXH=0 (This would increase overlap). I recently got a timing light and set my ignition timing to +17. I never had a vacuum gauge before, so I wanted to check it out. I tap the vacuum where the cruise control hooks up, so I could take it for a drive and test decel if you want me to.

 

I'm going to try a different vacuum gauge when I can get one. Perhaps this one is broken.

 

I think you just nailed the problem. There is no way an engine is capable of pulling 30+ in. of vacuum. 28 inches is about the maximum that can be pulled without having a two stage rotary vane pump such as is used in industrial, laboratory, and HVAC industries.

 

*smacks forehead*

I just noticed the needle was not exactly at the zero before applying vacuum. I pulled the needle off and zeroed it, but I bet it's still off a bit. It's reading 20.5 in hg now.

Sorry to waste everyone's time.

 

I have a 2000 Si turbo charged and my boost gauge reads about 21 23 hg at idle. and at decel its a little more but then it falls back to 21 23. I have all stock internals!