SR20DET O2 Sensor and ECU issue - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

GLoBaLReBeL420 · 05-25-2017, 02:39 PM

So, I've already read and done my research, but hoping there might be some kind of known workaround for my issue . .

What I got...
Engine: Early Model SR20DET Blacktop
Wiring Harness: Early Blacktop
ECU: Early Redtop E62 ECU

It seems after researching that my problem with the car running super rich is due to me using an E62 (Early Redtop ECU) with my Early Blacktop wiring harness.

Link for research = O2 Sensor Issues

With that all in mind let me tell you what I've tested . .

O2 sensor plug wiring: All get perfect continuity and setup correctly on plug

Different O2 Sensors: I've tried both a 4 wire to 3 wire Fatty O2 with no luck, and a 3 wire Skinny O2 with no luck as well. Both sensors when head to a butane torch flame provide readouts, but the ECU doesn't get anything.

At this point I would like to test out an E5/E6 ECU (Early blacktop) to see if the above link is correct in that I need it to complete the O2 sensor circut and provide the ECU with a reading.

But, until someone in SoCaL can help there, I was hoping someone else might have any idea on what else I can do to resolve this issue? Any help is greatly appreciated!!!

-Matt

*e1_griego* · 05-25-2017, 02:43 PM

The redtop and blacktop harnesses are the same. The one that is different is the late model blacktop harness that comes with j4 ecus.

What's the rest of your setup? Auto or 5spd chassis originally? I've run into issues trying to run a 5spd lower harness on an auto car where the alternator is pumping out way too much voltage and making the car run stupid rich.

GLoBaLReBeL420 · 05-25-2017, 03:12 PM

Harness = Manual transmission

Per the link I put in there it seems that there is a difference in the wiring loom of the red and black top harnesses. One grounds out to the intake manifold(redtop) and one needs a ground point to the ECU(blacktop).

The engine and harness are all out of a early blacktop MT as far as I know (is there a way to verify this?). The chassis is a 1973 240Z, but that has no bearing on my issue as the engine and ECU are totally separate from the chassis wiring.

I know my alternator is not working as good as it should as I only get 13.06 when charging engine on, (read via Nistune and/or NDS) and I know it should be high 13's to 14.

Can you think of any tests I can do to rule anything out? I already tested continuity for the signal wire and both ground/power wires from the O2 sensor plug on the harness side. All check out good.

GLoBaLReBeL420 · 05-25-2017, 03:51 PM

Quote:

Originally Posted by e1_griego

The redtop and blacktop harnesses are the same. The one that is different is the late model blacktop harness that comes with j4 ecus.

What's the rest of your setup? Auto or 5spd chassis originally? I've run into issues trying to run a 5spd lower harness on an auto car where the alternator is pumping out way too much voltage and making the car run stupid rich.

Meant to quote you but no luck hah. Did respond tho!

GLoBaLReBeL420 · 05-30-2017, 07:47 AM

Just bumping this hoping for an update/opinion...

05-25-2017, 02:39 PM	#1
GLoBaLReBeL420 Leaky Injector Join Date: Aug 2005 Location: Orange,CA Posts: 117 Trader Rating: (2) Feedback Score: 2 reviews	SR20DET O2 Sensor and ECU issue So, I've already read and done my research, but hoping there might be some kind of known workaround for my issue . . What I got... Engine: Early Model SR20DET Blacktop Wiring Harness: Early Blacktop ECU: Early Redtop E62 ECU It seems after researching that my problem with the car running super rich is due to me using an E62 (Early Redtop ECU) with my Early Blacktop wiring harness. Link for research = O2 Sensor Issues With that all in mind let me tell you what I've tested . . O2 sensor plug wiring: All get perfect continuity and setup correctly on plug Different O2 Sensors: I've tried both a 4 wire to 3 wire Fatty O2 with no luck, and a 3 wire Skinny O2 with no luck as well. Both sensors when head to a butane torch flame provide readouts, but the ECU doesn't get anything. At this point I would like to test out an E5/E6 ECU (Early blacktop) to see if the above link is correct in that I need it to complete the O2 sensor circut and provide the ECU with a reading. But, until someone in SoCaL can help there, I was hoping someone else might have any idea on what else I can do to resolve this issue? Any help is greatly appreciated!!! -Matt Last edited by GLoBaLReBeL420; 05-25-2017 at 03:14 PM..

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05-25-2017, 02:43 PM	#2
e1_griego Premium Member Join Date: Sep 2004 Location: Independence, Ore. Age: 36 Posts: 2,642 Trader Rating: (24) Feedback Score: 24 reviews	The redtop and blacktop harnesses are the same. The one that is different is the late model blacktop harness that comes with j4 ecus. What's the rest of your setup? Auto or 5spd chassis originally? I've run into issues trying to run a 5spd lower harness on an auto car where the alternator is pumping out way too much voltage and making the car run stupid rich.

05-25-2017, 03:12 PM	#3
GLoBaLReBeL420 Leaky Injector Join Date: Aug 2005 Location: Orange,CA Posts: 117 Trader Rating: (2) Feedback Score: 2 reviews	Harness = Manual transmission Per the link I put in there it seems that there is a difference in the wiring loom of the red and black top harnesses. One grounds out to the intake manifold(redtop) and one needs a ground point to the ECU(blacktop). The engine and harness are all out of a early blacktop MT as far as I know (is there a way to verify this?). The chassis is a 1973 240Z, but that has no bearing on my issue as the engine and ECU are totally separate from the chassis wiring. I know my alternator is not working as good as it should as I only get 13.06 when charging engine on, (read via Nistune and/or NDS) and I know it should be high 13's to 14. Can you think of any tests I can do to rule anything out? I already tested continuity for the signal wire and both ground/power wires from the O2 sensor plug on the harness side. All check out good.

05-30-2017, 07:47 AM	#5
GLoBaLReBeL420 Leaky Injector Join Date: Aug 2005 Location: Orange,CA Posts: 117 Trader Rating: (2) Feedback Score: 2 reviews	Just bumping this hoping for an update/opinion...