Ok so what ive gathered is that on my 86 GXL the exhaust ports need back pressure to open. But what I cant figure out is how the back pressure triggers the auxiliary ports? When I looked in my repair manual all it had was the air pump port setup.

 

No.


The aux ports need the prssure from the exhaust flow to open in an S4 engine. The exhaust ports are always open. (i think you know this, but accidently said otherwise.)

There is a tube that runs from the cat to the aux port actuators. Im not certain on the S4, but on the S5 there is a solenoid that controls when pressure is seen by this actuator. Like a wastegate actuator it opens at a certain pressure. When the solenoid opens the actuator is exposed to the pressure in the exhaust pickup tube and then the port opens.

Someone correct me if I am wrong. I understnad the S5 setup, but im not 100% on the S4.

BC

 

There's a small approx 3/16ths pipe that runs from the Split Air Pipe to a pipe next to the rear auxillary port actuator. It feeds pressure to both actuators thru that pipe.

Put a piece of vacuum hose on that pipe next to the rear auxillary port actuator and blow real hard. The actuators should open a bit or at least move. I'm talking the lever on the actuators.

Or use low pressure shop air. Like 10psi or less and blow into that pipe. The actuators will move if not disabled.

http://wombat.sevarg.net/RX7/RX-7_Training_Manuals/ and page 4-15 of the FUEL AND EMISSIONS section at that site.

 

The actuators should open fully with normal human lung pressure.

There should also be no leaks when you're pressurizing it with your lungs - once the actuators have moved to the fully retracted (S4) or extended (S5) position, you shouldn't be able to blow any more air in. If it's leaking, especially if the leaks prevent the actuators from opening properly with your lungs, they're not going to work right.

-=Russ=-

 

Just to clarify...

On the S4's, the split air pipe goes from the back of the intake manifold (which has an internal passage from the air control valve) to the main cat. Going from the cat to the IM, near the IM you'll see a small nipple ~3/16" welded to the split air pipe. Then, you see the split air pipe enlarge for the built in check valve, which prevents exhaust going past it to the Air Control Valve. The exhaust back pressure (combined with the air pump pressure when the ACV sends air to the Split air pipe) pressurizes the actuators, which retract the arms and open the auxiliary port valves/sleeves. This is how the 6PI (6-port-induction) system works.

On the S5's, the air pump solely provides the pressure, the air to the auxiliary valves passes through a solenoid valve which the computer opens when at a set RPM.

Now the thing I wonder about... there are screws on the bottom of the actuators, and I'm sure there's a spring in them...I wonder if one can adjust them to retract/extend at a lower pressure (i.e. when you have a less restrictive exhaust). I have searched for this but haven't exactly found an answer. Aaaron, Icemark, other experts - this is for you!?!