I have some questions about an sr20 motor harness. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

brickerj · 04-07-2012, 06:08 PM

I redid my motor harness a while ago and I wasn't getting power to pin 109 (I've seen this labeled as both Reverse electrical flow return circuit (alternator fail input) or ECCS backup power on different pinout diagrams on the web). I was using this to power my injectors so, I just put a jumper in from pin 36 (ignition on) and everything worked. I'm currently redoing my harness again because my setup has been moved to a new chassis and I would like to fix this mess because it doesn't seem right to me.

So my questions:

1) is pin 109 even supposed to be powering the injectors? If not, where do the injectors get power from?

2) where is pin 109 really supposed to be wired from?

3) where does pin 109 get power from? Is it switched from the ecu (my ecu is faulty) or is it really supposed to be jumper from another power wire?

Thanks in advance to anyone that helps!

Ok, so just in case anyone searches for this and needs the answer I will answer my own question.

According to the English S14 SR20 manual that is so common online pin 109 and pin 58 come together and the injectors get power from the ignition switch. Problem is pin 58 doesn't exist on any of the pinout diagrams I've found (maybe it's different for S14, I don't know). So I did a little digging and I found a Japanese version of an S13 SR20 manual and was able to decipher enough from the pictures to see what is going on. Pin 109 and pin 46 (ECCS backup power) are connected and this powers the injectors. So when I hacked it up before I was almost correct, just need to jump from pin 46.

Kamronman · 08-03-2012, 08:13 PM

Did you ever get more information on that pin 109? My ignition power stays on when I pull the key out because of the eccs relay not operating properly.

If I jumper the power to ground inside the eccs relay circuit, the car/fuel pump/(maf/cas) will all work and the car will run. But I'll have to unplug my battery to shut the ignition power off..

My question is this, What is the black/white wire coming into the eccs relay supposed to have as far as voltage goes? It seems when the ignition is off with battery attached, (didn't put the key in and turn it yet) then the voltage reads 0. BUT, while the ignition is on doing it's problem with the key out, there's 1.22 volts at that black/white wire. Where I'm guessing is supposed to be just the switched ground by the ecu to operate the cas/maf/eccs relay/ and reverse electrical flow return circuit.

04-07-2012, 06:08 PM	#1
brickerj Leaky Injector Join Date: Oct 2011 Location: Delaware Posts: 51 Trader Rating: (4) Feedback Score: 4 reviews	I have some questions about an sr20 motor harness. I redid my motor harness a while ago and I wasn't getting power to pin 109 (I've seen this labeled as both Reverse electrical flow return circuit (alternator fail input) or ECCS backup power on different pinout diagrams on the web). I was using this to power my injectors so, I just put a jumper in from pin 36 (ignition on) and everything worked. I'm currently redoing my harness again because my setup has been moved to a new chassis and I would like to fix this mess because it doesn't seem right to me. So my questions: 1) is pin 109 even supposed to be powering the injectors? If not, where do the injectors get power from? 2) where is pin 109 really supposed to be wired from? 3) where does pin 109 get power from? Is it switched from the ecu (my ecu is faulty) or is it really supposed to be jumper from another power wire? Thanks in advance to anyone that helps! Ok, so just in case anyone searches for this and needs the answer I will answer my own question. According to the English S14 SR20 manual that is so common online pin 109 and pin 58 come together and the injectors get power from the ignition switch. Problem is pin 58 doesn't exist on any of the pinout diagrams I've found (maybe it's different for S14, I don't know). So I did a little digging and I found a Japanese version of an S13 SR20 manual and was able to decipher enough from the pictures to see what is going on. Pin 109 and pin 46 (ECCS backup power) are connected and this powers the injectors. So when I hacked it up before I was almost correct, just need to jump from pin 46. Last edited by brickerj; 04-07-2012 at 07:40 PM..

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08-03-2012, 08:13 PM	#2
Kamronman Join Date: Jul 2012 Location: NorthWest Posts: 14 Trader Rating: (1) Feedback Score: 1 reviews	Did you ever get more information on that pin 109? My ignition power stays on when I pull the key out because of the eccs relay not operating properly. If I jumper the power to ground inside the eccs relay circuit, the car/fuel pump/(maf/cas) will all work and the car will run. But I'll have to unplug my battery to shut the ignition power off.. My question is this, What is the black/white wire coming into the eccs relay supposed to have as far as voltage goes? It seems when the ignition is off with battery attached, (didn't put the key in and turn it yet) then the voltage reads 0. BUT, while the ignition is on doing it's problem with the key out, there's 1.22 volts at that black/white wire. Where I'm guessing is supposed to be just the switched ground by the ecu to operate the cas/maf/eccs relay/ and reverse electrical flow return circuit.