5.5 psi,, with MBC? WTF!?!??!

[SuperSpud]

ok,, I have had the Joe P mbc for about a week.. I had it set at 9.5 psi.. the first week was great,, it would hit and stay at 9.5... last night,, I was watching my boost gauge, and when I hit boost,, 3,300,, it would go to 9'ish,, stay there until 4000,,, then go down to 7 psi.... the only gear that holds 9.5 is 5th..

when I downshift from 5th to 3rd,,, it goes all the way down to 5.5psi.. WTF!?!?!?

what could this be?

 

[flat_black]

Vaccum leak, would be my bet... Best way I've found to find these, is run the car, rev it by pushing the throttle body control lever, and listen for whistles. If you don't hear any, grab a spray bottle with soapy water, and spray it along the intake tract, and the vaccum hoses, and watch for bubbles.

 

[nattyboy513]

the lever is really hard to reach on our cars...

 

[flat_black]

Yeah, I wasn't sure how it was on the Mazdaspeed, as I THOUGHT the intake pipe was a little thinner, but I may just be crazy. =) Mine's a b**** to reach, too, sorta, but with all the times I've worked on my RX-7, I don't even notice how difficult it is to reach stuff on this car. Hehee.

 

[SuperSpud]

well,, it does reach the psi I set it at,, if I had a leak,, wouldnt itnot do that??

 

[SuperSpud]

Re: YEP

Man that was the very same thing I experienced. You like me have that certain bad hose. I had gone from 11 down to 7 and couldn't get any higer at all. It would hit 11 for a split second then drop to 7. I left the car running found the leak and sealed it with a very small zip tie.
I found the suspect hose just by moving it around and hearing the sound change from a steady hiss to spoosh-spoosh-spoosh sound.

yeah,, I was going to replace that whole stock hose.. with a rubber one... all the way from the waste gate to the MBC... I already bought the whole turbo vacuum hose set form a mazda dealer,, so I can put that on if I need to take it in..

yashooa, whats your AOL AIM name?? mines superspudUH hit me up

 

[ZMN BY U]

Well mines reading 3 psi today i hooked it up and it reads 3 psi so whats the problem i have the fp kit from joe but its on a different vac line. HELP