OK, so the turbo control solenoid that sits on top of the ACV, what exactly does it do? Ive searched and looked at my FSM and the only thing I can see is that it is energized in vaccum areas, but I havent really found a clear explanation of its purpose. Also can this solenoid be eliminated when getting a boost controller or only the Pre-control/wastegate control solenoid?

-Farris

 

There are two turbo control solenoids - one operates on vacuum, one pressure. If you are staying sequential, they certainly cannot be removed.

 

http://www.autosportracetech.com/RX-...erOverview.htm

The function of the solenoid is to control the turbo control actuator (TCA) from regulating exhaust gasses from primary to secondary. Prior to 4,500RPMs, it is off to regulate most of the exhaust gasses to the primary turbo. The TC solenoid is notorious for sticking under increased boost pressures.

 

I am working on this as well. I am having secondary boost issue, on 1st and 2nd gears.
I have a question about testing these solenoids. I have the vac one out (the one that set on top of the acv). I guess when you power the solenoid, it re-route the air passage. well my question is the plastic cap that is on the unuse end, should it seal the passage so it will hold vac when it is route to the cap. my is leaking vac, i guess it is gone right?? some one please help.!!!

 

Follow the How To link on http://rx7.voodoobox.net/ for a detailed write up on testing solenoids.

 

I did read up on that site but no one really had mentioned anything about the cap. The cap has a MITSUBISHI logo on it. ( I guess mazda was using their part back then).
The way that I understand the system work is when you put power to the solenoid (above 4500RPM, it will let vac get to the TCA. But when you are under 4500 rpm, the solenoid get no power and it will reroute the vac to cap. Now if the cap is venting all the vac. would we be losing all the vac in line. ????? wondering if i need to seal the cap???
please help

 

Most times those caps are just vents to atmosphere - part of the design. It can switch between vacuum and atmospheric pressure.

Don't try and plug or seal anything up.

Dale

 

Don't seal the cap. It acts just like the filters on the other solenoids.

Dave

 

Both of the turbo control solenoids work together to open the turbo control valve. This is the main valve that feeds air to the secondary turbocharger, and if the solenoids aren't functioning (or lack vacuum or pressure feed), the TC valve will stay shut. So you need this.

The precontrol and wastegate, on the other hand, drive the precontrol valve and wastegate valve. They are the other two valves on the hot side of the turbos.

Dave