Bruceman

iTrader: (5)

Car is slow to accelerate from 5000 to 8000 rpm in second gear. I mean it is much slower than my 1st gen 12A. So I've wanted to check whether the 6PI system is working.
With the engine idling I can ground the non power side of the 6PI solenoid valve (brown) and I see the actuators open. So this tells me the mechanical/air pressure side of this system is good.
I checked the resistance of the wire (blue with white? stripe) from the solenoid to the ecu (pin 3R). That measured .04 ohms. So that tells me the connection to the ECU is good.
I tried to use the ohm meter between the solenoid to ecu wire (disconnected from the solenoid) and earth while I was driving to see if the ecu switched to ground. But did not see it happen. So this tells me the ecu is not activating the 6PI system.
Am I missing something? Why wouldn't the ecu activate the 6PI?

1990 Rx-7 GTU
Standard S5 engine with all emissions
A/C removed
Fresh rebuilt engine by me

Barwick

Mr W I presume? How's Waterford Hills been going lately? I haven't made it up there lately.

I haven't dealt with an N/A in a long long while, but is it actuated by RPM only? And at .04 ohms, is it possible the wire is shorted somewhere (somewhere that's a bad bad ground) between the 6th ports and the ECU?

HAILERS

Your doing things wrong. Put the meter on volts dc and backprobe the wire of the 6PI solenoids plug that is NOT black/white.

Go for a ride. The meter will read approx 12vdc until you reach 3850rpm where the voltage drops to less than 2vdc. Zero would be less than 2vdc and any figure inbetween.

See page F1-81 of the series five FSM.

Bruceman

iTrader: (5)

Barwick
No I'm not Bruce Wentzel.

Hailers
That sounds good I'll try that tomorrow night

Bruceman

iTrader: (5)

Tried using the voltmeter to see if the voltage dropped but it does not. Stays constant at 14V throughout the rev range to 6000.
Tried this method for the VDI solenoid and the voltage did drop below 2V at about 5500 rpm. So at least that is working.
I'll check the operation of all the ecu 6PI inputs next.

Thanks for the help:[

Black91n/a

I had the same problem, everything worked, but no signal from the computer. I wired in a Summit Racing adjustable RPM switch and called it a day.

Bruceman

iTrader: (5)

Finally SUCCESS!!
The relationship chart (F1-76) in the FSM shows the inputs for the 6PI are the clutch switch, neutral switch, crank angle sensor, water thermosensor, and AFM. Of course the last sensor I checked was the problem, it was the sensor that I was sure was not the problem!
The CLUTCH Switch had a wire cut and this wire was connected to the other wire on the switch, which effectively causes a continuous ground so the ECU thinks you are changing gear and therefore does not allow the 6PI to work. It is now working.
Can't wait to drive it more and feel the increased power. I have also noticed other differences in the car after fixing this such as on decelleration the exhaust note is different (fuel cut) and a pop out the exhaust when you get back on the throttle. Also the idle is different.

I found a good way of determining whether the 6PI are opening. Well 2 good ways. The first is to run a wire from the 6PI solonoid front terminal (this is the grounding wire from the ecu) into the cockpit, connect a voltmeter to this wire and ground the other voltmeter wire (cig lighter is good for ground). When the engine is running the voltmeter reads charging voltage (13-14v). When driving with foot flat to the floor, engine speed above 4k rpm, the volts will drop to about 1 volt when the solonoid activates the 6PI.
The second method is to install a one way valve in one of the hoses to the port valve actuators. Then if the 6PI solonoid allows air pressure to the actuator it will open and stay open because the check valve will not let the air pressure release the actuator. So you drive the car then stop and look under the hood at the actuator rods to see if it is being held open. If so then the 6PI is working.

SpikeDerailed

iTrader: (7)

Wow...thank you so much Bruceman, that relationship chart helped me figure out why my car wasn't pulling for crap at top end. This was def a helpful thread A+ would read again.

My car is a ATX -> MTX swap, and it was done before I got it...half-assed at that, I have been trying to do it right and fix the errors, and they never did anything with the ATX inhibitor switch(light always indicates park), which has to explain why I don't feel like I have any top end. According to the relationship chart the inhibitor switch is one the things that controls the 6pi opening.

blwn rtr 89'

iTrader: (5)

you fellow mi natives should come help sand some paint