I need some help. My 93 FD has had boost problems since I bought it. I just compleeted the vac hose job and some other mods all at the same time. Before all these mods my boost has always been erratic on the highway I would get 10 lbs on 1st turbo if I eased into the throttle but 0-5 psi if I stomped on it, and if trying to launch from a stop I would get 0psi. My turbos have been replaced by my warranty recently for oil leaks and the problem remained the same. Occasionaly when the throttle was stomped the boost would stick at 1-2psi and as soon as you got off the throttle there was a loud peeeuuu sound then if you applied the throttle slowly the boost would build fine to about 10psi. A friend found one of the lines coming off the pressure tank loose on the bottom end I replaced this and the peeeuuu sound and the boost sticking at 1-2 on hard acceleration stopped but it still didn't boost right boost would drop off on the second turbo.

Any way since then we took it all apart put in all new silicone vac hose, mid pipe, down pipe, pettit ecu, cold air intake, block off plates for acv, egr, double throttle, aws, under drive pullys, and a joe p boost controller. Per the boost controler instructions I turned the boost controller way down went for a drive I had like a 5-3-5 pattern I thought this was good correct pattern just a little low. So I turned it up some still just 5lbs, didn't get into the #2 turbo. got out turned it up some more 5lbs. We ended up turing it up as far as it would go still 5lbs. We put in one of the needle valve controlers and still got 5lbs no matter what the valve was set at. I drove around some last night and thought I could hear pressure blowing off while at 5 lbs like the blow off valve was open or somthing, and now the boost sticking and the peeeuuu sound has returned just not as loud. Please help me I just want to have a properly boosting FD for once in my life. Thanks Jeff D.

 

Please does anyone have any susgestions?

 

I'm not sure about the boost controller part because I don't have any experiance with that. As far as before, it sounded like you had a bad solenoid. The TCA might have also had a problem with it. All I know is non-sequential is so much easier. I got fed up with my problems, went to non-sequential. I get about 14 psi now w/o fail.

 

Check for boost leaks in the intake piping. This is a good site for trouble shooting such problems http://home.istar.ca/~dvandit/rx7stuff.shtml

 

Thanks for the link P'cola. When we put it back to gether we pressurized the system and the only leak we could find was from the oil dip stick. If I held that down then I couldn't hear any leaks.
Now that I think about it how was pressure from the intake able to come out the dip stick?

 

WOW - i had exactly the same boost pattern as you 5-3-5, and like you i assumed it was something simple.......

......and it was ! Check your dump valve. Mine had a split diapragm which was basically allowing the boost back to the airbox so i never built up more than 5 psi.

Chris

 

Do you mean the blow off valve? Does any one know what's up with pressure coming out the dip stick? I capped off one of the hoses going to the air box and put this pressure tester on the other the only leak I heard was the Dip stick? This dosen't sound right that boost pressure could come out the dip stick hole. Does anyone know what's up with this?