i was wondering what cause low vac on my boost gauge?...bout 3 days ago it was reading 20-23 hg. and it was park ever since...i havn't touch or drove the car until today, i cranked it up,let it warm up and now its reading 10 hg... id checked for vaccum leak and thers no sign... any tips would help...

 

Is it idling rough?

 

well i was having problem w/ the surging...but it was reading 20-23 hg when it was surging 3 days ago...still surging and now reading 10 hg...the idle is pretty smooth...its reading 10 hg from cold to fully warm..

 

Vac leak can show a low reading on the gauge. check all your hoses and the gauge it self.

 

bump for mo info...

 

sounds like a leak to me, thats the about what i read when I leave something unhooked.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sinner &raquo;</TD></TR><TR><TD CLASS="quote">sounds like a leak to me, thats the about what i read when I leave something unhooked.</TD></TR></TABLE>

id check and no leak...id change the IM and tb gasket too

 

vacuum leak is the only thing i could picture.... is your idle up and down, because i get that alot with mine and somebody had mentioned it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boosted EM1 &raquo;</TD></TR><TR><TD CLASS="quote">vacuum leak is the only thing i could picture.... is your idle up and down, because i get that alot with mine and somebody had mentioned it? </TD></TR></TABLE>

yea it idles betwen 800-1200 rpm....

 

vac leak or compression

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by z6 &raquo;</TD></TR><TR><TD CLASS="quote">vac leak or compression</TD></TR></TABLE>

i havn't do a leak down check on it,but i did a compression test on it and it was 185 psi across the board..

 

so pretty much if you have a vacuum leak your idle is going to be really low and rough... because you arent getting enough air and that cause the engine to run super rich??? later Mike

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slowhonduh93 &raquo;</TD></TR><TR><TD CLASS="quote">so pretty much if you have a vacuum leak your idle is going to be really low and rough... because you arent getting enough air and that cause the engine to run super rich??? later Mike</TD></TR></TABLE>
No, a vacuum leak wopuld mean it's getting too much air. The idle speed would be higher or bouncing. Running lean more likely.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca &raquo;</TD></TR><TR><TD CLASS="quote">
No, a vacuum leak wopuld mean it's getting too much air. The idle speed would be higher or bouncing. Running lean more likely.</TD></TR></TABLE>

yea but my idle is pretty smooth...

 

whats your base ignition timing at becasue if you are running a low base timing it will cause a low vacuume, also do you have camgears becasue excessive retardation of the cams either one will cause low vacuume. compression also, like allready stated.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rainforest &raquo;</TD></TR><TR><TD CLASS="quote">whats your base ignition timing at becasue if you are running a low base timing it will cause a low vacuume, also do you have camgears becasue excessive retardation of the cams either one will cause low vacuume. compression also, like allready stated.</TD></TR></TABLE>

my ign is set at stock...and the cam gears are at 0 deree...