How To: Installing Titana O2 Sensor in your 84-85 300zx

up next, now we have to make the vehicle's harness compatible with the Titania sensor.

in order to do this we simply need to trace out the yellow wire ( the one that would go to pin 115 ) and simply cut it and then ground the path that leads to our o2 sensor connector.

I found that the best spot to do it would be right around this area.



make sure you put some heat shrink on the open wire that goes back to the ecu( just to be safe)

next locate the bolt that is towards the back of the Upper Intake Manifold and find a circle type connector that the bolt will fit through.




next make sure you crimp the connector piece to your spare wire.



heat shrink it up to make it look nice and neat-like.



test fit the new harness piece and line every thing up the way you want it.



make sure to slip some heat shrinking onto the wire before you solder it!




twist the 2 wires together neatly and evenly, try not to let any strands poke out.



Solder the 2 wires together (if you don't know how to solder you can substitute with a crimp type butt connector) -- but you should just learn to solder it though. lol



slide the heat shrink tubing over the newly soldered portion of harness and then heat it with the lighter.



tuck everything back into the harness and use a zip tie or something of the like to make it all look tidy again.



and presto, it almost look like it belongs there.


OK, so now you have the electrical part of things figured out.

the last part of the guide is just the Bung in the o2 elbow.

If you bought the titania type o2 bung or pulled it out of the t25 o2 elbow, it is interchangeable, just need a 32MM socket to get the old bung out and swap the new one in, then you are done.

I, however just found an adapter on ebay for less than ten bucks.




when all the way tightened it will show all of the fins of the o2 sensor.



so when installing, install the bung into the old Zirconia sensor bung(make sure you put that thread locker on the outside threads) --- just in case you need to replace the Titania sensor in the future.



simply apply some thread locker to the outer threads ( the ones that make contact with the actual elbow) and start threading it in, twist it in as far by hand as you can, then install the o2 sensor into it. thread that down as far as you can by hand then pull out your 17MM wrench.

tighten it with the wrench as much as you can, you want to make sure you crush that little metal washer.

you'll notice how much easier it is to use a 17mm wrench in that small space compared to the damn 22MM wrench… LOL.

and THATS IT YOU ARE DONE!

the outcome:

i noticed my car accelerated faster, and had better throttle response.

to me, it was worth it.

THANKS FOR READING

Great job!

Why do people swap ECUs??

It's common to swap from an 84 or 85 ecu to a later year for a few reasons. Most commonly us the start up fuel enrichment on early ecu does not tend to work as well as the later 87+ ecu.
Not to mention the maps in later ecu to me feel better and more responsive.
Going from na to turbo also requires changing the ecu aswell.
Many people swap ecu and just leave o2 plug disconnected. But that seemed to me a rookie way to do it. I wanted proper o2 feedback thrown into the mix. Also to achieve closed loop.

I used an 87na ECU on my 84T with the zirconia O2 sensor (can't remember if it was plugged or unplugged) and it definitely had better acceleration response and no lean start issue, but it ran rich and my mileage was horrible.

Thanks for the writeup! This has been on my list of things to figure out (wiring wise) but hadn't got to it.

Right, I also plan to swap the 87na into my 84T. never heard of swapping a 87T though. just seems like a hassle because of the sensors. 87na and 84T share the same sensor type IIRC

If you are running an 87 na ecu it WONT WORK on your 84 T.
The calibration is for na 180 cc injectors Not 260 cc that are on turbo.
Unless you are nistuning the 87 na ecu.

Take the chip from an 87T ECU and swap it into an 87NA ECU to retain zirconium 02, you will lose knock sensor capability. A cheap Radioshack desoldering iron is all you need.

I thought running NA solved the cold start issue.

http://www.redz31.net/pages/fuel.html

That's not exactly true. It's the fact of switching to a later ecu. If you have an 84 or 85 na, your going to want to use an 87 na ecu.
If you have an 84 or 85 na, you would want an 87 T ecu.

And as far as tearing apart 2 ecu's to swap prom chips. That's fine if you have the money to spend on 2 ecu's and then have the ability to desolder and solder computer chips.

For me just doing my conversion was the easier and far more cost effective route.

???

I think he means
If you have an 84 or 85 na, your going to want to use an 87 na ecu.
If you have an 84T or 85T, you would want an 87 T ecu.
?

I used this guide here too:
http://www.redz31.net/pages/fuel.html
when selecting a 87na ECU to try and fix my cold start issue, as the O2 sensors are the same and the injectors are both low impedance.
I never read anywhere that the ECU cal was different for the different CC of the injectors, it was selecting the right impedance.

Actually i think i misspoke above, i think it might have been the 88T with internal dropping resistors and an unplugged O2, that ran rich
in my 84T.
When i ran the 87na ECU, i think it had a too high of an idle ~1200rpm, so i put the 84T ECU back in.
It's been a few years since i messed with this stuff.

The rewiring of the O2 sensor seems pretty easy, and reversible if needed.

Quick look at Nistune shows a setting of 560uS for 87t injector and 750 for 88t, so even with dropping resistors your latency is way out.
Which might explain the rich condition, since the ECU thinks it's running slow (high impedance) injectors thus giving it the extra time to open and close. Running an extra 90uS of fuel per cycle?

I did the ECU/ O2 sensor conversion four years ago during the NA2T swap. However… about two years ago I dropped in a VG33 and for some reason I don't even remember addressing the O2 sensor.

My idle is high and mileage not so great but, I attributed that solely to vacuum lines needing to be replaced. I need to revisit this. Thank You for the write-up les_joey_paul and posted comments which add further clarity.