jmc92380

i have a bone stock 93 auto and my car seems to boost up to 10 psi and then after in 2nd gear it wont go over 6 psi and it feels like there is some sort of leak

David Hayes

iTrader: (6)

Boost should hold at 10 PSI until 4,500 RPM where it should dip to 8 and then recover back to 10. I would go do a run in 3rd gear and watch what happens to the boost.

Prior to this, have you checked the hoses that attach to the turbos? I've had the hose connected to my secondary turbo come off. When this happens, you'll make 10 psi boost until 4,500 and then it'll drop and just stay at around 6 or so. Could be the problem. I'm assuming no smoke is coming from your tailpipe right?

jmc92380

a very little bit of smoke when i first start it up

dgeesaman

iTrader: (7)

Your turbos are fine. If they're bad, you'll get heavy smoke out the exhaust when you get hard on the boost.

I'll bet if you don't have a leak in your vacuum rack, that you have a bad check valve. When you're boosting and it starts to get weak, let off for a second and get some manifold vaccuum, then boost again. If that restores full boost, you can bet on needing a new check valve. On this diagram it's the one in the green line:
http://www.davidgeesaman.com/rx7/93v...lor.edited.jpg

Dave