Currently have a boost pattern of 10-5-10. The boost pops to 10psi no problem but the crossover is a hairy one. Once the crossover begins the boost falls to 5 psi. Now the boot may come back up to 10 psi right away or it will slowly struggle back to 10 psi depending on load and rpm.

I've been assuming the whole time that this has to to with the turbo control actuator and the related systems. So far I found a leaky check valve that connects to the pressure box, but this has not fixed my problem. Is the box supposed to remain pressurized after the engine has been run? Mine does not, but I have yet to double check since I've replaced the valve.

My vacuum box holds vacuum just fine, even days after the engine has been shut off.

So it seems to be that the solenoid may be bad. Am I on the right track or am I looking in the wrong place?

Also, I don't mean to throw a wrench in the whole thing but the previous owner had 2 mbc's installed. I've played with them a bit but I haven't seen it change my problem. I don't think these are of concern, but I thought I'd say I have them just in case.

 

Have you done the KOKO test? If not, check this thread about doing that and see what happens:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/11-8-4-5-pattern-strange-sound-certan-rpm-723333/

 

don't have anyone at the moment that can help me with KOKO, but I've found that my pressure chamber does not hold pressure. I ran some regulated shop pressure to the inlet of the chamber and found that air is escaping near or at solenoid E. Is it supposed to bleed off air at all or is this a faulty solenoid? What is the proper operation of this solenoid?

 

ok found that the control solenoid nipple broke off. I'm going to use jb weld for a temp solution until i can get a new solenoid.

 

took her for a drive. it still is 10-5-10. but it doesn't struggle to get back to 10. It is nice and snappy.