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Too much vacuum pressure?

9K views 4 replies 3 participants last post by  Jackstand Johnny 
#1 ·
So it's been while since I have had any problems with the suby but over the weekend I seem to have a sudden odd reading on my boost gauge. During normal driving my vacuum pressure would read around -20 but now it seems to have increased to around -30? And I hear an odd noise coming from under the car, not where at I cant seem to pinpoint it. My exhaust doesnt seem to even sound the same either? I looked under the for a hole or something but didnt see anything. Anyone have any trouble shooting ideas?
 
#3 · (Edited)
It idles fine and boost fine but I'll give it a look over today.
Also noticed the noise from under the hood doesn't become noticeable till the gauge reads below -20.
It wont make any noise if Im in neutral but if I put it in gear and the pressure drips below -20 it makes some odd noise but if I hit the gas and get it above that it will stop?
Would the turbine on the turbo make a noise only under vacuum, because it makes no noise what so ever when I boost?
This has got me stumped??
 
#4 ·
I know my 02 WRX with its original EJ205 idles at around -8 until its warms up, then its around -12. Ive never seen the gauges on my accessport go lower than -14. Im at sea level with a stage 2 tune by the way. Do you have a way to check for vacuum and boost leaks? What constitues a "weird" noise? A whining? Sucking sound? A whistle? are you unable to walk around the enigne with it running and listen for when it gets louder? Have youdone any work to your engine recently?
 
#5 ·
And you should also do more than just look for a hole. Look for line coming off at the nipple, splits in any hoses...physically grab the lines and bend them etc to see if it changes any idling or running conditions. You can also try the starter fluid method. To me it would make sense that a vacuum leak wouldnt cause such a strong vacuum. If anything it wold be a boost leak but even then Im not real sure how. How does it drive? Are you underboosting? Is this a stock engine or has it been modified or tuned?
 
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