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vacuum pressure

grand2000prixgtp

grand2000prixgtp

New member
ok. i posted a thread about this before but i still cant seem to find my leak. my boost gauge reads 0 at around 1000 rpm and when it revs up to 3000 it has -20psi. i have checked all the lines and they seem to be fine. but when it is at 3000 rpms i can head a really high pitch noise and i have had my dad look while it is making the noise but no luck. so i am totally lost and i don't really have the money to bring it some where to get it fixed. it started after i put my headers in. any idea on to find it if there is a step by step or anything that would be great.
 


So your having a vacuum when you go WOT? That's not right. And I don't see how. I would say there is an issue with your boost gauge going off of what you have told me so far.

Regarding the high pitched noise....The PCV valve may need to be replaced. It's in the S/C housing. Take off the two 10mm bolts.
 
in your previous thread you said you checked for vac leaks did you check the gauge (if it is mechanical)?

Btw my gauge reads -11 at idle, am i having a problem too!!?! The car seems to run fine. Stock pulley, mods in my sig (plus a DP).
 
You will always have a vacuum at idle. Your suppose to. But not when you are at PT or WOT. Because the throttle blade is all the way open therefore there is no vacuum present in the LIM.
 
TDCRacing said:
You will always have a vacuum at idle. Your suppose to. But not when you are at PT or WOT. Because the throttle blade is all the way open therefore there is no vacuum present in the LIM.
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yea i know but i just put my headers on and now i have no vacuum i have look at all the lines. and im nit sure where to look next
 
People in the other thread say idle vac is supposed to be around 15-20. Mines only 11, i mean the OP's is 0 so hes in worse shape then me i guess lol.
 


Ok. If that is acting normal (Increasing when you get on it and showing nothing when you are at idle) then I would say you have a bad or gauge or something.

If it is saying you have boost when you are at idle then you more than likley have a issue with a vacuum line.
 


grand2000prixgtp said:
when my car is trying to idle it wont stay running and i cant even drive it
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What else did you tke off besides the headers? You may have a huge vacuum leak. Take some carb cleaner and spray around the LIM gaskets and all of the other areas and see if you hear the engine rev up.


That's the only thing I can think of.
 
If it wont stay running I say it is a vacuum leak and will have to find it somewhere. I dont think a bad gauge would effect how it runs mechanically.


FYI......on my car.....
Idle in park- -15 to -21
When in the throttle while driving 0 to +9 psi depending on RPM's and weather conditions.......
Normal driving depending on how into the throttle anywhere from -9 to +9
At a stop light while in D= -18 to -15

This is all according to the aeroforce scan gage........
 
TDCRacing said:
What else did you tke off besides the headers? You may have a huge vacuum leak. Take some carb cleaner and spray around the LIM gaskets and all of the other areas and see if you hear the engine rev up.


That's the only thing I can think of.
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just the headers thats all
 


Liquifire said:
If it wont stay running I say it is a vacuum leak and will have to find it somewhere. I dont think a bad gauge would effect how it runs mechanically.


FYI......on my car.....
Idle in park- -15 to -21
When in the throttle while driving 0 to +9 psi depending on RPM's and weather conditions.......
Normal driving depending on how into the throttle anywhere from -9 to +9
At a stop light while in D= -18 to -15

This is all according to the aeroforce scan gage........
Click to expand...
yea i disconnect the gauge and it didn't change anything
 
Do you have someone to help troubleshoot this. If so you said that it made a high pitch noise(assuming that this is not the SC) at 3000 rpms........open your hood and have one person rev it( short term) in this range to see if you can hear were this noise is coming from if nothing else works.........Check all fittings too. You could have a large crack in the plastic somewhere where the hose is attached if you bumped anything or pulled on an attached hose when doing the headers...... You are 100% sure that you have the EGR sealed off?
 
I know the brake booster line is huge and would create a large loss if disconnected....not sure what else is that large that would create a full vacuum loss.
 
Liquifire said:
Do you have someone to help troubleshoot this. If so you said that it made a high pitch noise(assuming that this is not the SC) at 3000 rpms........open your hood and have one person rev it( short term) in this range to see if you can hear were this noise is coming from if nothing else works.........Check all fittings too. You could have a large crack in the plastic somewhere where the hose is attached if you bumped anything or pulled on an attached hose when doing the headers...... You are 100% sure that you have the EGR sealed off?
Click to expand...
yea it is sealed of but i had a friend listen and he thinks that where he heard it from but he was not sure
 
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