I'm in the process of reviving a 2003 350z. I'm almost done but I'm having an issue with the front 02 sensors. the plugs on the sensors don't match the plugs on the engine harness. The sensors are 4 wire plugs whereas the plugs on the harness side are 6 wire. Nissan has 2 different part numbers for that sensor, I just need to know which one to buy. I should probably mention that this harness was from a 2004 Z.

 

Its possible the 6 wire o2 is a wide band and the 4 wire is narrow band.

I would recommend buying the o2 sensor for the 2004 z since thats what the computer will be expecting. also the 6 wire o2 may cost more money but will be worth it in the end. I wouldnt recommend splicing wires to get it to work with your harness.

 

I would probably get a Nissan replacement (so far everything that was missing was replaced with an OEM part). The cost is a lot compared to what I make but at the end of the day id rather do a slower build and have a solid car in the end. Luckily I have one 6 plug O2 already.

The ECU is a 2003 so I'm kind of worried there will be differences in the plug at the ECU, like the pinouts being different, but I'll figure that out later.

 

Research is always a good thing . The 2004.5+ cars have wide band O2 sensors while the early 03 and 04 cars have narrow band sensors. I would expect the wide band sensors will not work with the 03 ecu and the wiring harness connection to the ecu might also be different. If they ecu fits the 04.5 harness you might be able to get away with splicing the narrow band sensors into the the harness but I have never look at the wiring diagram and have no idea if this is possible.

 

Ive tried searching quite a bit but couldnt find anything definitive. I have no problem doing a bit of rewiring or switching pins around. I custom built the engine harness on my S13 so that I could use all S14 engine parts.

Could I just purchase a 2004.5+ ECU and another 6-pin/wideband o2 sensor, or would that be incompatible with the body harness or other sensors on the motor?

If anyone has a link to the ECU pinout diagrams that would be awesome.

 

The factory service manuals has wiring diagrams for the ECM. It looks like the 03 ECM will plug in to the 04.5 harness but at least the O2 sensors use different pins. From a quick glance everything else looks to be the same pins so you might be able to switch a few wires around and have an 03 harness.

 

Thats pretty much what I needed to know, thanks man.

 

Your welcome and good luck! If you can, post an update when your done. I'm interested to see how it turns out.

 

Will do. I can't wait to get this thing running finally. My honda is boring as ****.

 

Alright so I found everything in the FSM for both the 03 and 04.5 as far as pinouts go. Has no one put this into an excel sheet yet? It's the only reasonably quick way of making a comparison that I can think of.

 

so wideband o2 sensors have 6 pin and narrow has 4 pin? my 2005 Nissan 350z (aka z33) 35th Anniversary Edition 6 M/T REV UP with dual vvti has pre cat 6 pin and post cat 4 pin i was told that every 350z only has one kind its always either 4 pin pre and post or 6 pin pre and post so wtf is goin on

 

Thread was from 5 years ago.

6-pin pre and 4-pin post should be correct since it was switched over to this in the newer models from what I read above.
I do know that 4-pin post: 2 pin is for heater catalyst, 1 pin for ground, 1 pin for O2 sensor. Not sure why there be 6-pin for the post...?