OK, I found this a while back on some Japanese website. Fortunately the ECU pinouts were in Japanese text, so I used Google to translate into English.

Attached is the document in question. It's a zipped MS Word document, and the original webpage I found the text from is at the top.

I do have a few notes in there that I made, and I have in bold some of the pins that are different to the US ECU's.

The goal of this is to figure out how the JDM ECU's are wired up. If we could sort this out, we could probably make the warning light function truly useful and maybe have a bit better idle control.

I've noticed that there are a few extra JDM pins that don't have a US equivalent. I just went through it again last night, but really need to go through and make some notes.

Again, I'm not 100% sure if this information is super accurate. The majority of the pinouts seem to line up with the US pins, so that's cool, but I don't know for sure if this is for a '93-95 car, or if it's for a later revision.

Anyhow, let's see if we can put our heads together on it!

Dale

 

Just dug around dude's webpage - he's working on an N3A7 ECU, which is a JDM 93-95 ECU, so we're good there.

Dale

 

I have a JAP import and i use a few wires for login, but i use pin 2b for my Inovate LMA-2 RPM convertor, i tap my RPM from 2b, it says diagnostic connector on yours.


Only pins i can confirm on a 1992 r-type jap spec are

1M : Vehicle Speed Sensor

1O : MAP Sensor

1S : Brake Switch

2B : Tachometer output

3C : Primary O2 Sensor

3E : Engine Coolant Temperature Sensor

3F : Throttle Position Sensor

3L : Intake Air Temperature Sensor

4A : Ground

Let me know if i got the wrong end of the stick and if i can help anymore.

Great work though

 

I know it is a lot to ask but if you ever get the chance, tracing the Check Engine Light back to the ecu would make a lot of people happy (if we can get it to work on our car)

 

The problem is I don't think JDM cars have check engine lights. I have a JDM cluster in my garage - no check engine light, but it does have an exhaust overheat light on the cluster.

Also, I know the JDM cars have a better exhaust overheat system - there's actually a temp probe that installs in the main cat to monitor cat temps. I think it's a thermoswitch, though, and just closes the circuit at a certain temperature.

Dale

 

Holy Smokes, I think I've got it!

Check this page out -

http://www3.tcn.ne.jp/~yyyy/p-fc/ecu.htm

It's another pinout list. I think the culprit is pin 1V - that's nothing on the US harness, but in this pinout it says heat warning lamp! On the other one I posted it just says "meter" for that pin.

BTW, there do seem to be one or two errors on the link posted above - water temp sensor is shown twice, for example.

But, here's the differences I've found -

1V - overheat lamp (yay!)
2I - US heat hazard sensor, JDM it translates to "kiyataanpu", original word is キャタアンプ.
3B - US EL Unit, JDM AC Amplifier
3J - US EGR switch (Cali), JDM rear defroster
3K - Solenoid Relief 2, JDM is blank
4F - Split air bypass, JDM is blank
4O - EGR solenoid US, JDM seems to be TNS (tail, number, stop - ie, parking lights) input
4P - US AWS system, JDM the second link shows as a fan input or output, but that could be wrong.

I think my harness from Autosport Wiring has ALL the wires run - if so, I can play with wire 1V. But, I don't have a Datalogit to change the warning points to test. Yeah, I know .

Anyhow, I think I'm on to something here!

Dale

 

Well, I just got done re-wiring the check engine light to pin 1V on the ECU. So far, so good - light comes on with the key in the On position and goes off when you start the car. In theory, this is it!

I'll keep an eye out - I RARELY see over 60 knock, and I never see crazy high duty cycle, so I dunno if it will come on for me. You Datalogit guys with your lights rewired should give this a go.

Dale

 

you the maaaan!! i've been digging round for ages. you rock!!

 

Set the two warnings down low and test it out for us.

 

I can't - I have no Datalogit, and the Commander will just let you turn the warning on or off.

Yeah, I need to get a Datalogit .

Dale

 

http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWA:IT&ih=010

 

Driving to a call this morning, I got on it on an uphill grade and lost traction a bit. Many times when I lose traction, I get some drivetrain noise that shows as false knock - sure enough, I did, and the Check Engine light blinked at me a few times!

So, this confirms it - pin 1V is the one to tap into. Problem is the US harnesses don't have a wire on pin 1V, but you have a few options.

1) If you pulled the pins out of the harness instead of cutting the 4 wires, you can push one of those pins into the hole for 1V, cut the wire, and tap the end of that wire into the wire heading to the Check Engine light.

2) Go to the junkyard, find a Mazda vehicle from the '90s, and find the ECU connectors. Mazda used very similar ECU connectors for many of its cars in the 90s - just snip a whole connector off, take it home, back a pin/wire out, pop that in 1V, wire up.

3) I guess you could also open the PFC up and solder a wire to that terminal inside, but that would be pretty tricky, and I don't like doing anything to the PFC itself if I can help it.

4) Get an Autosport Wiring harness (http://www.autosportwiring.com/) - it's a short harness that goes between the ECU and stock wiring harness. I have one and love it - I tap all my electronic doo-dads into this harness and don't have to worry about permanently screwing up my stock harness. All ECU wires are hooked up with this harness - I just tapped into the 1V wire and was done.

Anyhow, I'm glad we finally solved this mystery!

Dale

 

Great work, now which wire goes to the CEL?

 

That's in this thread -

https://www.rx7club.com/power-fc-forum-47/hopefully-making-pfc-warning-light-function-useful-534888/

I'll try and do a writeup soon to put all the data in one place.

Dale

 

Be sure to link it...

 

good work, thanks for sharing dale.

 

...waiting inpatiently for the writeup...

 

In case you didn't find it, the writeup is here (PDF doc linked therein): https://www.rx7club.com/power-fc-forum-47/how-make-your-knock-injector-warning-light-work-620175/

 

Yep yep! But thanks for the heads up!

 

is this turbo2 j-spec ecu pin out?

 

Nope, this is for the FD.

Dale

 

I wired mine up here recently and was able to check out its function. Problem is that mine comes on at startup and stays on. I believe it may be that I don't have a fuel temp sensor and its causing a CEL light??? Could some try unplugging their fuel temp sensor and seeing if the light just stays on? If would be appreciated, I don't want to got to the trouble of wiring in a resistor (temp sensor simulator) if it won't work either way.