Hi, I live in Australia and have not long upgraded from a 1st gen Rx7 to an Rx8,
I have used the Rx7 as a track car for the past 8 years with some success and now
starting to develop the Rx8.
I was hoping if somebody could help me with wiring the Greddy rpm adaptor 3 to the Rx8. we where hoping to use the adaptor for our shift lights.


From the instructions I have wired the adaptor's yellow wires x 2 to the leading coil trigger wires (green on leading coil & yellow with green tracer on the trailing coil,) then black wire to ground and the brown wire to shift lights, but after wiring it the engine only runs on 1 rotor , after removing the adaptor the engine runs fine.
The ECU pin numbers for the coil trigger wires are 2AA & 2Z, are these the correct wires and if so what am I doing wrong ?.


Any help would be appreciated.


Thanks SRRX8

 

Try yellow channel 3 to rear leading and yellow channel 4 to front leading

 

Thanks for the reply Brettus, as I only have the adaptor with the 4 yellow wires and one black and one brown which yellow wire is channel 3 and channel 4 , I also wrote the wrong coils in my last post, it should have said I connected one yellow wire to the front leading ( green wire) and another yellow wire to rear leading (yellow with green tracer) and left the other 2 wires spare as how I interpreted the instructions, I then connected all 4 yellow wires 2 to each ecu wire but still no luck, am I interpreting the instructions right or should I also have an additional harness that connects the adaptor to my ecu.?

 

I'm still trying figure out why you'd need to tap into more than a single coil if all you're trying to do is read RPM.

 

You have a 4 channel just like I do. I'm experiencing the same issue. The channels are not labeled I'm assuming they go in order. I'm currently working on this as well for my boost controller.

This is necessary because if you only tap into 1 rotor leading it only it reads half the rpm.

 

I would think it would be double not half. Weird. Perhaps I'm over simplifying it by thinking of a timing light.

 

According to the Greddy instructions you need to tap into 2 coils to get a correct signal, one coil you only get half .
I have had a good look at the instructions again and the illustration shows the
4 yellow wires then black wire then brown so maybe the channels are in that order.
I will try that and let you know.

 

Ok, tried that and still nothing, one thing I did find is when you connect the
yellow channel 3 wire to the yellow/green ecu wire the engine runs fine but checked for a rpm signal and nothing, but when you connect the yellow channel 4 wire to the
green ecu the engine drops onto 1 rotor, I am just wondering is the Australian spec
RX8 ecu pin numbers the same as the US version and I am connecting to the wrong
wires ?
If not is this a faulty Adaptor from Greddy?

 

AU and US wiring for ignition is the same

 

Thanks Shelldude, I thought as much, I'm going to go back to the ecu and triple check the wires that I have connected to are the right ones and if they are then its not looking good for the Adaptor

 

Same problem Greg has been having by the sound of it .... Seems like the adr drags voltage from the wire and there isn't enough left to fire the coil . What coils are you running ?

 

Hi Brettus, genuine Mazda coils that are not that old, what voltage are the coil wires
supposed to have.?

 

Not sure ........
Greg has BHR coils ... was wondering if it was peculiar to those . Obviously not .

 

Just checked the voltage on the green wire .384 volts and the yellow/green wire is .424 volts at idle. Also you would think that when I connect the green wire and the engine still runs fine that we should at least get half a signal from the Adaptor, but there is nothing at all.

 

that's a strange voltage ...are you measuring voltage or voltage drop ?

Also , what is it with and without the adr ?

 

I will check with the Adaptor connected and get back to you, the voltage was with the engine running, checked when just ignition on and it was zero, using a good quality
multimeter.

 

Just checked the voltage again, both wires when the car is cold have .630 volts and progressively drop as the engine warms up, this being that the plugs need less voltage to fire as the engine warms up, when I connect the Adaptor yellow wire to either wire the voltage drops to .15 volts on both wires but the engine only drops to one rotor when you connect the green wire not the yellow/green , very strange.
Also the engine will not drop to one rotor if you don't have the earth connected
from the adaptor, I am really starting to think this is a faulty adaptor.

 

Could anybody tell me what the correct PCM to coil voltage should be at terminals 2aa & 2z with the engine running please.


Thanks

 

I don't think you have a faulty adapter as I have the same issue and have tried a brand new 4 channel adapter from greddy and a used older 2 channel with the exact same results.

 

Gregs, you may be right as I wrote earlier that the engine would drop to one rotor
when we connected the Adaptor and that started to ring alarm bells as what was happening to the trailing side of that rotor, so today I started to fully test the ignition system and found a faulty coil on trailing number 1 rotor, the coil passes the ohms test but as you know that is not always the absolute guarantee that the coil is good.
So I swapped the coils over and it is faulty ,I also tested them with a timing light and it shows the same result. So I have ordered one new coil to try and if all good will replace the lot. They are not that old either.
Back to my previous question what voltage do you get out of the PCM at terminals 2aa & 2z I have looked thru the workshop manual and it only shows checking with
an oscilloscope on 2 volt setting, can you test this with a multi meter on the rx8 or
do we need to use an oscilloscope.?

 

SRRX8 run a 1k resistor inline between the rotor 1 and 2 leading coil and report back with your results. I have a feeling you will be pleased with the outcome.

 

Gregs, just to double check, the resistor will connect between the green and the yellow/ green wires then connect the adaptor as per instructions

 

That's correct

 

Gregs, how many watt resistor

 

I used a 1 watt