redrotary91

hi, i have a 1991 rx7 with 113k and i recently had it taken to a shop for spark plug and wire replacement. the mechanic told me when he took it for a test drive he thought the "secondary intake port" wasent opening, which he said was suppost to happen at 5k and that my "port door" wasnt closing which is suppost to be at 3.5k?



this is the one he called the secondary intake port, its on the rear right side of the block. i tryed to jiggle it and its really stiff. i havent gotten it to open at any rpm. i also pulled the hose off and can bearly feel suction.



this is the one the mech called port door. it moves freely, i still need to check if i can get it to open.

the shop i took my car to is the only shop in town that would touch a rotary, and they were still reluctant. the only reason they did is because one off the mechanics drives a fd. so im not sure how accurate their information is. this is my daily driver and i put about 550 mi a week on it mostly city miles.i havent noticed anything really strange about the way it drives just attributed it to being a rotary vs piston. it likes to stall out when starting it first some times, then as soon as i engage the clutch it comes back to life tho.

so my question is how accurate is my info? whats ports are those and what rpm do they open?

thanks

(edit:pics soon)

bumpstart

if its an NA then he is referring to the aux port switching
which in a 91 model is done with air pressure from the air pump /acv ,, and in pre 89 from the exhaust backpressure

if its a pre 1989 turbo,, then "port door " could be the twin scroll flap on the turbo ,, but since yours is a 91 ,, and i guess NA then its likely the VDI valve ( variable dynamic intake )

this amounts to short-cutting the airflow in the manifold and also allowing front and rear rotors to pulse charge each other for high rpm operation

i am not so sure that you can emulate their operation with just a free rev
- and if these valves are faulty it is likely related to the control circuits and the air pump routing
( though the aux ports can have trouble with carbon lock )

RotaryRocket88

iTrader: (7)

The first picture shows an aux. port actuator, which is intended to open at 3800 RPM. There are 2 of them, and they open what some people refer to the 5th/6th ports (6 port engine).

The second picture shows the VDI actuator, which is intended to shorten runner length at 5200 RPM. VDI = Variable Dynamic Intake. There's an explanation at the bottom of this page: http://homepage.mac.com/carldavis/intake.html.

As bumpstart mentioned, the air pump supplies pressure for these actuators, but the ECU controls them with a pair of solenoids. The 6PI and VDI solenoids are on the emissions rack, and have plugs that are brown and white respectively. I think the S5 FSM has some testing procedures for them.

redrotary91

Thanks for the info guys. and merry xmas to all fellow rotary heads
OK so apparently he told me the rpms mixed up. i applied grease on the aux port actuator and have been driving for about a week and it hasn't been smeared so its still locked up. Do you think im causing significant damage by driving like this? I've been keeping it under 3k since i found out the condition.it is NA btw.

RotaryRocket88

iTrader: (7)

You can't really do the grease test on S5 aux. actuators. The rods push out when pressure is applied, so the grease won't move. The S4 versions pull in, which would let you do the grease test.

I don't think you can just free-rev the engine to 3800 or 5200 RPM to watch the actuators move, but you can test the actuators and solenoids themselves. The actuators should be fully open with 1.4 psi (6PI) and 2.8 psi (VDI). The solenoids should switch & allow airflow with battery power applied. This all comes from from pages F1-42 to 47 of the S5 FSM.

Another quick and dirty way to see if the systems are working is just unplug the two solenoids. If power takes a serious hit, they were working! Or at least one was. The two combine for about 40hp up top.

Aaron Cake

iTrader: (1)

If you disconnect the boost/pressure sensor and free rev, the port might open.

redrotary91

Ok so here’s where I’m at now, I drove without the solenoids connected and it feels the same. (Or normal to me since I assume it’s been this way since I bought it, 11k later). I’ve checked the solenoids and when electrified they will allow air to pass and the rear aux port will open but the front will only move a little bit. The vdi solenoid also passes air when activated, the port mechanism seems to work, although I don’t feel anything at 5k.
So what’s next? I check between ecu and solenoid? What else does the air pump supply, could that be it?

where is the pressure sensor?

RotaryRocket88

iTrader: (7)

The pressure sensor is on the passenger-side strut tower. It's a black box that'll say N3xx.

If one of the aux. port actuators is not moving all the way, it could be getting stuck, or the sleeve inside the block (what it turns to open the port) could be binding. Removing the actuator for cleaning or replacing is simple, but getting at a stuck sleeve means removing the whole intake manifold.

Another possibility is old vacuum lines leaking. Check the line on the actuator that isn't moving, and trace it up to the metal hardlines. If it's hard or cracking, replace it with a new piece of hose.

The air pump supplies air to the ACV, which directs it to the exhaust ports and main cat for emissions, but above 3500 RPM it only operates the 6PI and VDI. Excess air is dumped out the side of the ACV to a plastic muffler near the washer fluid.

redrotary91

ok, so i've narrowed the problem down to electronics. i can bypass the solenoids and just blow on the vac lines and they will move. so then i hooked up a multimeter to the solenoids and took a spin around the block and i dont get a reading. so my problem is my ecu not telling the solenoids to actuate? how do i fix the connection?

redrotary91

bump, still puzzled. i cant find the vdi or 6pi solenoids on any wiring diagrams. i've checked haynes and the faq here. i did a little experiment too, i ran a vac line straight from each the vdi and 6pi actuators from engine bay to cabin and have pressurized them at the appropriate rpms while in gear. and i didnt get a noticeable difference.