Turbo pressure

[hartdlh]

Ok, here it is another stupid question. My mkiii is the first turbo i have owned so I dont know that much about how they work, only what I have read. My question is on a mkiii what should the turbo guage be reading at idle. second, if i rev the motor up should my guage move. My wont do anything unless im driving down the road.

[projectsupramk3]

That's not a stupid question, everyone has to start somewhere. Your engine will not build boost at idle or while reving it, simply not enough air flow. A healthy engine should pull 20-22 vaccume at idle, max boost should be 5-6psi stock.

[hartdlh]

ok so you do not build pressure at idle. so at idle what will the factory guage read? should it read 0 or -4? Thats what im not understanding.

[projectsupramk3]

-4psi is what it should be sitting on at idle on the stock gauge. On an aftermarket gauge it should read 20-22in.hg

[hartdlh]

Ok i got it. Thanks for your help

[MKIIIKamel]

Actually I'm having a problem with my boost gauge also. When I turn on my car at idle the gauge reads zero. And when i start driving it stays at zero at doesnt go up or down for that matter. i have no idea what the problem could be if someone can help me out id appreciate it. oh and i tried swapping the boost gauge with another stock boost gauge from another 88 supra only to get the same results.

[DaMoNe6969]

Originally Posted by MKIIIKamel

Actually I'm having a problem with my boost gauge also. When I turn on my car at idle the gauge reads zero. And when i start driving it stays at zero at doesnt go up or down for that matter. i have no idea what the problem could be if someone can help me out id appreciate it. oh and i tried swapping the boost gauge with another stock boost gauge from another 88 supra only to get the same results.

the stock boost gauge is not very accurate and very slow to respond.. You really havta lay into that gas peddle before the boost gauge will jump.. But if your gauge is indeed dead, Its probably a leaking vacumn hose or bad turbo pressure sensor..

The turbo pressure sensor is under the hood on the driver side fender.. check the vacumn lines running to it, and check to see that they have vacumn at idle.. if not, the vacumn line has come off somewhere between the manifold and the sensor.. If the vacumn is good, your turbo pressure sensor is probably bad