Thanks to all of you who have contributed, and thanks to all those whose work I've studied on the net (for other cars)!!!! This is my compilation of info that I've pieced into a "how to" guide.NOTE: IGNORE THE COLORS ON THE PIC BELOW!!! THAT IS NOT THE CONNECTOR FOR A R32 RB20DET!!!!!My RB20DET, from a 1993 R32 RB20DET, has a 14pin connector about 14inches up the wire harness from the ECU. However, this 14pin connector does NOT have the proper signals wired to it...so some re-wiring is in order if you want Datascan to work.

Here are your basic signals and what wire they should connect to on the CONSULT cable. (NOTE: If your wiring seems to be different, then DO NOT ATTEMPT to follow this guide. I am only making this guide based on my experience of this ONE ENGINE ALONE!!!!)

ECU Pin #____Signal Name_____Color___________Color on CONSULT USB 21___________RX_____________Yellow/Green Stripe______White22___________TX_____________Yellow_________________Yellow31___________CLK____________Yellow/Red Stripe________Blue45___________IGN____________Black/Red Stripe _________Red47___________CHK____________Yellow/Purple Stripe _________NOT NEEDED..believe it or not..



Now you will see that the USB cable has one more wire: a black one...this is a ground wire, but we'll get to that at the end of this guide.

Now you know what wires are needed and where to find them. Using wire-taps, tap into the ECU wires 21, 22, 31, and 45. Use Male connectors to run wires from your wiretaps to the consult port.

Now, assuming your Consult port is not plugged into anything, we can assume that these wires are dead-ends and are of no importance. Plug in your USB cable to the port. ON THE CAR SIDE OF THIS CONNECTION, move 2 or 3 inches up the wire and cut the 5 wires that match the USB wires.



Using the wire-tapped extension wires, connect the appropriate signal (above) to the wire that will match the appropriate USB wire color. This part is most easily figured out with the 14pin connectors PLUGGED IN!! You will do this for the RX, TX, IGN, and CLK wires. Of the 5 wires you have cut, the last wire remaining should match the Black wire on the USB side. Sure enough, use this 5th wire to run to a nearby chassis ground.

If your software and proper drivers are installed, then plug in the USB cable, turn the key on (or start the car, either one), and click "connect" on your Datascan software!!! Goodluck tuning!!!



Any corrections or added info can be posted on this topic.

--TJ

Modified by s13_240_rb20 at 2:03 PM 2/18/2008
Modified by s13_240_rb20 at 7:46 AM 2/19/2008

Also, I have noticed that my Datascan software only connects to the ECU (whether 'key on' or idling) if this plug behind the glovebox is unplugged.



The 4 main wires used for Datascan are on this plug, along with the pin#46 wire (A/C) and three wires going to the engine bay...I don't know any more than that, or what this may affect.

Anybody have any input on this plug, what the other wires are, or why the RX, TX, etc wires are going this way??

would this be the same or similar for the KA24E?

LSDrift wrote:would this be the same or similar for the KA24E?

I don't know because this write-up is based on the RB20DET and its ECU/wiring harness. However, I have heard that the KA24E did not come with a consult port "pre-installed. One will have to be wired in." You can probably use the chart above to understand what Signal should match up to what USB wire, but it is your responsibility to make sure that you trace each signal to YOUR OWN wiring, which may have different coloring/pin #'s. Check your FSM and search for a complete PINOUT for your ecu.

--TJ

Do you happen ro hav the pinouts for the 3 incabin plugs??? I labeled most of them but I'm still missing 14 wires (they go to the engine side of the loom).

what about wiring in a r32 rb26 ecu? help plz!

s13_240_rb20 wrote:ECU Pin #____Signal Name_____Color___________Color on CONSULT USB 21___________RX_____________Yellow/Green Stripe______White22___________TX_____________Yellow_________________Yellow31___________CLK____________Yellow/Red Stripe________Blue45___________IGN____________Black/Red Stripe _________Red47___________CHK____________Yellow/Purple Stripe _________NOT NEEDED..believe it or not..



Now you will see that the USB cable has one more wire: a black one...this is a ground wire, but we'll get to that at the end of this guide.

Now you know what wires are needed and where to find them. Using wire-taps, tap into the ECU wires 21, 22, 31, and 45. Use Male connectors to run wires from your wiretaps to the consult port.

Now, assuming your Consult port is not plugged into anything, we can assume that these wires are dead-ends and are of no importance. Plug in your USB cable to the port. ON THE CAR SIDE OF THIS CONNECTION, move 2 or 3 inches up the wire and cut the 5 wires that match the USB wires.

Modified by s13_240_rb20 at 2:03 PM 2/18/2008

Modified by s13_240_rb20 at 7:46 AM 2/19/2008

OK I understand how to find the wires on the ecu.

How do I connect them to the usb cable? Usb cable has red black green white and the shield? how are the 21, 22, 31, and 45 and ground connect to the usb? Which order when looking at the usb plug?

Very interesting. I wonder what a Power FC would do if connected to the laptop this way.

Sooooo.....I hope this page has helped many many Nissan fans!!!

However, I have not ever really had to depend on Datascan to troubleshoot anything...ever. I am posting a pic of my datascan screen and I need someone to look at the readings and tell me why it feels like it is not tuned correctly. It feels like it is supposed to be more powerful. My RB20DET is now in a Nissan Hardbody pickup, and I pretty much "adjusted" EVERYTHING under the hood trying to make it start and idle before I found a couple of wiring errors. Now I have no idea which sensors are tuned incorrectly.

I have a very tight-feeling clutch pedal and a stage 2 clutch installed when I did the swap, but when I leave a red-light, I have to rev/clutch a few times and it launches sorrier and slower than my KA24 sohc hardbody....it isn't supposed to be like this I have to rev super high to spin the tires but even then it is a let down...

The readings you see in the picture at taken at IDLE.....I am most curious about my TPS, Timing, and Injection because those are the ones I "adjusted" back and forth. (and I am pretty sure my O2 sensor is not working...probably part of my powerloss due to running rich?











After turning the TPS down slightly and, more importantly, turning the CAS clockwise 1/2 of an inch or so.....It launches even worse, tends to backfire a little bit around 4-5k rpm, but it has better acceleration??? Here are the readings, at idle, after the two adjustments I just mentioned...



As you can see from before and after photos of the datascan software, I already know the TPS adjustment also dropped my rpms by about 1000rpm, and my CAS adjustment dropped my timing down significantly...

But what is the "perfect tune"?? For an idling RB20DET, what SHOULD these numbers be??????

Thanks,

--TJ