5/6th auxiliary ports not working
 

Hey guys,

i have a problem with my '89 gxl and i hope that at least one of you could help me.

my aunt bought the car in 89 and drove it for about 10 years before she gave it to my father. he drove it for a few years but stopped driving it 2 years ago and now it has been sitting unused ever since.

my father said that the 5th and 6th ports haven't been working since my aunt still had it and we can't figure out why that is. we tested the actuators and they are fine, all the vacuum hoses are where they are supposed to be and the solenoid valve is also fine. we have concluded that the ECU isn't sending a signal to the solenoid valve because the wire is also fine. we plugged in the cable from the vdi valve to the 6pi one and when we went over 5500 rpm the actuators moved.

according to the factory manual the auxiliary ports are only opened above 3800 rpm and under load. because of that my father thinks that either the air flow meter or tps are not telling the ECU to activate the 6pi or the ECU just doesn't wanna do it.


thanks in advance to anyone who has suggestions on how to tackle this problem


ps: we also have to replace the oil metering pump because it shows up among the error codes (6pi doesn't) but we don't think that this is relevant

How do you know that the 5/6th ports aren't opening while driving besides just hearing about it? Easy way to test out if the ECU is throwing a voltage to the solenoid would be to hook up a multimeter to the plug for the solenoid or at the ECU (back probing the correct wires) and look for the voltage as you drive (with the help of a passenger of course).

It would be really odd if you have a bad ECU that is only not activating the auxiliary ports, but still probable. If you had a bad OMP, they are also known for taking out the ECU when they go bad so maybe something happened during that time???? Most of the time when this happens you are left with a dead ECU though.

Test the voltage coming off the ECU (take note of the color wires on the plug for the solenoid) and report back. Search around for the factory service manual (FSM) for an Series 5 (S5) as that will help you out with the testing procedures. There is also a separate electrical manual with all the pin-outs floating around here and the web if you need it. I suspect the ECU is fine, but your wiring in between the ECU and solenoid is broken (but the ECU would throw a code if it doesn't "see" the solenoid). If the voltage test out fine, then time to look at your vacuum lines for clogs or mis-routing or double check that solenoid for clogs. The air control valve (ACV) should also be something to take a look at since it is what is responsible for routing the air from the air pump into your 5/6th ports (on S5's they open with the air pressure from the airpump when the ACV properly routes it to the solenoid)...

Bad AFM will cause your car not to run very well and you WILL know if that is bad, trust me. A bad TPS would not cause the auxilary ports to not work, only a bad idle and possible "backfiring" when letting off the throttle at high RPM. I haven't looked at the auxilary port system, but I am pretty positive it is based solely off RPM, meaning it uses the crank angle sensor, but I can be wrong on this...

Hope that helps out....

Forgot to mention:

The ACV can easily be checked by removing one of the hoses on the solenoid for the auxiliary ports. You should feel air PUSHING out. If you do, the ACV is doing it's job (it should be working fine from your explanation though).

Also, I re-read your post, you can ignore the part about getting the FSM and checking the air pump, ACV, and vacuum lines for clogs/misroutes. From your descriptions those should definitely be working and I just noted you already have the manual.

thanks for the response.

we'll check the voltage on the plug and hope we find something. the funny thing is that we also have a second ecu which also doesn't activate the 6pi system and we don't think that we have such bad luck that both ecus have the same malfunction.

If you don't get voltage at the plug (which you most likely won't), check at the ECU by back probing. Definitely sounds like broken wiring....

Can you drive it? What dose the car do when your driving it? If you think it is the 5th and 6th ports just remove them and block it off. If you block it off you not only made your engine bay less messy but gained a few horses too.

You loose more than you gain, this is coming from somebody who has and hasn't had functioning auxiliary ports...

Really? I noticed better acceleration when I removed mine. I had a similar problem it turned out it was the omp/ecu problem, but thought it was the ports.

If you’re interested in keeping the ports I would run them off the air pump. From what i read it was the way to go, I have had no firsthand experience with them.

Why would you run them off the airpump when they are already running off the airpump to begin with and the O.E. system is pretty much well designed??? That is really redundant. I don't know why your car would accelerate faster with non-functioning ports, it should be the opposite since you loose low end power without them (that is unless your ports were stuck closed).

They are not run directly off the air pump. If you split the line from the air pump to the ports, bypassing the solenoid valve ,its more direct thus better peformance, again from what i have been reading.

You are probably speaking of this: https://www.rx7club.com/2nd-gen-archive-72/how-air-pump-auxilary-port-activation-330310/ ?

Why suggest to the OP to do something like this when it would be must easier to fix the issue with the solenoid not activating for him? From what he has posted it just seems like he/she has a wiring issue to the solenoid. Doing what you suggested would have the OP running around gathering parts, removing multiple components from his engine (unless he wants non-functioning parts sitting there), only to replace it with a system that does the same thing to begin with in the first place (or even worse, if he keeps the stock components, he will have more clutter laying around due to using the extra hoses for the air-pump activation).

I don't see how running your auxiliary ports straight off the air pump will increase the "performance" of the engine when a perfectly working stock VDI/Auxilary port system does the same exact thing. In a way, it seems more complicated than the stock system since you will still need ways to relief air pressure to the actuators and you will have to "tune" the air pressure to open up at the correct RPM via relief sections on the tubing from the airpump to the actuators. The stock system already does this for you and very accurately.

thanks a lot for the help and brainstorming guys. i will check the car today or early tomorrow and let you know if the problem is gone.

Get a digital meter. Neg lead on a known gnd like the bkt that holds the ECU in place. The positove lead backprobes the Blue/White wire in pin 3R.

At idle the meter will read batt volage approx. Drive the car and go over 3800 rpms. Meter now reads lower than 2vdc. You can't help but notice the drop from 12vdc to less than 2vdc. Proves the solenoid is getting the gnd signal from the ECU to open the six port actuator.

It's also possible on a older car like this, that someone has put the wrong solenoid in the place of the 6PI solenoid. Look at the FUEL AND EMISSIONS section of the FSM and look at how the 6pi solenoid is configured in the picture..........with the way yours is configured. Where the small air filter is installed will be a easy way to see if it's configured right or wrong.

Got a cheap $6.00 digital meter from Harbour Freight??? Short meter leads? Just buy some small gauge wire and make the leads longer either by wrapping the new wire around the meter probes or??? whatever way you want. So you can drive and look at the meter on the dash as you drive over 3800rpm.

Gotta drive the car to see this. Not in the driveway reving the engine. Won't cut the mustard doing that.......although I bet there is a way to simulate it in the driveway. Maybe disconnec the TPS and pull the vacuum line off the pressure sensor and plug that line......and push the clutch in and then rev in the driveway. Never done that myself. Don't own a series five. Bet it might work though.