Do I Have A Leak?

[Woody1]

Hello this might not do jack bit its giving me the SH%Ts lol my boost gauge both factory and aftermarket don’t sit on -20 (vacuum) and -7 where they sat when I first got it, they now sit on -15 and -5 or near abouts, just wondering if I have a leak or something where should I start looking to find out this problem the mods I have on are.

Blitz Bov (note does it with the Stock BOV as well)

Boost Controller Manual (Does it without this on as well)

That’s pretty much it

Thanks

[mad082]

you have a vacuum leak. you should probably be able to hear a leak that big. pop the bonnet with the car running and listen for a sucking sound.

[MBS206]

The leak will be on the motor side of the throttle body also. No need to really check the IC piping.

[2gceffy]

iv got the same thing i can hear it but cant find it sounds like its under the inlet plentum or near injectors.. how hard would it be to replace every hose on a rb25?

[MBS206]

Use your hand. Once you put your hand over it. You'll feel it.

[Cubes]

Where does the aftermarket boost guage take its reading from?

If the stock gauge is reading different the first place to check is the vacuum hose that runs to the map sensor.

Its very common for the hose running to the map sensor to split.

Mine and many others have had the hose split where it connects to the map sensors nipple.

The map sensor will be located on the drivers side to the left of the brake booster.

The vacuum is within the plenum, so check all hoses running to it, inlet manifold gasket, plenum gasket, t/b gasket etc.

Ignore the bov and inlet piping as that won't alter the vacuum gauge reading

[Woody1]

Thanksheaps guys ill start looking =D but ah i cant hear a thing ><

[MrRx7s3]

Hey guys, instead of me opening up a new thread, what should a standard R34 GTT be sitting at idle? mines at -10 - -11? is that normal or is there something wrong here, thanks.

[jhjones]

Should be around be around -20 inhg if stock cams?

[Badgaz]

use some CRC or 'start ya bastard' spray to locate the vacumm leak..the idle will change if you hit the leak. spray around the areas where surfaces meet or where gaskets are used....also any vacuum hoses.

[MrRx7s3]

I did a at home pressure test and there wasn't any leaks, it's completely stock too, another thing also is that on the stock gauge it only has up to -15 if you convert the units, I'm stumbled with this one.

[MrRx7s3]

At home pressure test meaning, where the AFM sits, I removed the AFM made up a pipe that fits in there with a air valve, got my air compressor and filled it up to around 15psi and it held the air in not leaking anywhere.

[Badgaz]

did you put a brick on the gas pedal to open the throttle butterfly?

[MrRx7s3]

Umm well I guess you could call it a brick, the Mrs was holding the pedal all the way down haha lol.

[Badgaz]

lol...i'm stumped...maybe you've changed your Idle?

[MrRx7s3]

It's been like that since I bought the car, I've changed the idle and stuff now and its still the same.

[Badgaz]

if i'm to guess i'd do a leak down test next....make sure piston seals are good.

[Ben C34]

Or not worry about it and just drive the car.

Is there a specific concern? Otherwise boost on.

Edited April 11, 2014 by superben

[Badgaz]

lol yeah why not.... "just put the jandle into it and f**k yeah!"

[Bushy]

Hook up pressure tester after turbo, not before.