Mazda2ndgen

rx7.com says this about the haltech O2sensor:

"The Haltech 4 wire sensor is designed to plug into the Haltech wiring harnes but can also be used as a universal 4 wire sensor for improved accuracy. "

does this mean that i could buy a haltech O2 senosor, and rewire it just to use it as a reguar O2 sensor and not need the haltech. b/c i havent had good luck with the discoutautoparts replacemetn O2 sensors...

Scott 89t2

I've been told that 4-wire 02 sensors are 0-5volt not 0-1. so they would not work and probably fry the ecu. they could be used to replace your O2 if you had a 4-wire stock. the o2 sensor doesn't really do much. the ecu only uses it while crusing and light load. you can unplug it and it won't make much difference. gas millage might go down a tad. so just get a bosch or something. if you want it for tunning or a gauge you really need a wide band 5 wire O2, which are around $1000 with the unit and sensor.

Barwick

*bringing thread back from the dead*

Are you SURE the 4-wire O2 sensors are different voltages from stock? I mean SURE. I'm thinking of just ditching my old stock O2 sensor in favor of the 4-wire I already have in the car for the air/fuel gauge. It seems my stock O2 sensor is shot anyhow.

I was reading and it SEEMED like lots of people were using them as replacements for stock O2 sensors (either on other cars or on FD's I THINK)

deadRX7Conv

Some o2 sensors have different voltages or voltage curves.
You'll need to research the one you are planning to use.
You should test any 4-wire o2 sensor during use, before long term commitment. This means, if you use a 4-wire sensor, you should compare its output voltage with the Mazda spec from the FSM. Or compare it to the normal o2 sensor using a quality volt meter.

The difference between the 4 and '1-2 or 3 wire' sensors is usually accuracy/warmuptime/life.

A one wire sensor uses the exhaust as a ground. Next time you remove it, look how rusty the threads are.

A 4 wire sensor usually has its own ground wire plus a sensor heater(ground/power).
The sensor heats up quicker, can possibly burn of crud(100k+ life.....OBD2), and is more accurate because the grounds resistance isn't changing with the rusting of the exhaust threads and o2 sensor threads.

To wire a 4-wire o2 sensor correctly requires thought.
The o2 sensor heater needs a relay and needs to turn on with the ignition switch. The heaters ground should go straight to the battery. You don't want to add stress to the factory harness.
The o2 sensor's reference ground should go to the ECU and the last wire should either use the 1 wire spot in the harness or you could run it straight to the ECU to eliminate possible old wire resistance/corrosion.....

Wankel7

Please do not waste your money on the haltuner/halmeter o2 sensor displays and sensors.

You are not spending your hard earned change in the best way. For that amount of money (Haltuner and sensor) you can get the Greedy unit. From my reading it appears high quaility and is a better than the sensor and unit the haltuner is. But NOT as good as the wideband units.

I am all fired up about wideband sensors!

You can build your own wideband kit. From what I have read on this forum from people that have not read results on these kits call them crap. Mostly the reason they call them crap because they do not know about this kits.

Two people on the DIY-Oz forum have run their kit in parallel with the dyno wide bands. They were within .2 AFR. I am going to try to build this thing

Here is one website. It is the site for the Aussie kit.

For about 225 you can have a wideband running in your car! Hell, if you have a palm pilot there is a guy who has software that lets you put it on it! Imagine that...Your AFR displayed on your palm pilot? And it datalogs. You can hotsync back to your computer. Does the autometer, haltuner, greddy do that?

http://www.techedge.com.au/vehicle/wbo2/

The hard part right now is finding a sensor. I think the parts bin.com has just got a shipment in. I placed my order bout 10 minutes ago.

These narrow band sensors are really just for a rough indication. They are only truely accurate at 14.7:1 AFR. Get a wideband and spend your money wisely.

James

Wankel7

Oh, if you want a haltuner mine will be up for sale soon

James