Jeff B. in Michigan

Good day,

I would like to know your opinion(s) regarding the accuracy of narrow band vs wide band O2 sensors. The scope of my interest relates to tuning and determining proper air to fuel condition under full throttle boogie.

It is my understanding that most OE vehicles (including our 4Runners) use narrow band O2 sensors. It is also my understanding that the narrow band sensors are not liner. This causes accuracy problems which include:

1) Inaccurate air to fuel readings when used to drive simple air to fuel meters (including the ARM-1). My investigation to date indicates that narrow band sensors will actually indicate a rich condition when they heat up even if the true condition is dangerously lean. I believe this is why the ECU's provide a fuel map circuit that is used when the stock O2 sensor stops working under high temps.

I have found two companies that produce a wide band O2 controller that is used with a wide band O2 sensor. These units are a bit pricey but if I am on track with my thinking they are the only way to determine true on the road condition (even a Dyno equipped with exhaust gas analyzer cant simulate actual on road / track conditions). For more information about the two products I found visit:

1) http://plxdevices.com This unit seems to fit my needs the best. It provides a narrow band output that you could run to your ECU. This way you don't have to add a third O2 sensor to your exhaust pipe (U just replace the stock sensor with the wide band). Additionally, you can interface the wide band output of this unit to the Autometer air to fuel meter.
2) http://www.fjoracing.com/

Thanks for the information.

Jeff B in MI
http://N8RWS.COM

Gadget

You are absolutely right. Narrow band sensors are only accurate right at 14.7:1 air/fuel ratio by weight. They are very inaccurate above and below that.

Wide band is the way to go for tuning.

I got one of these and it seems to work pretty well, but that PLX one looks very interesting.

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

Gadget

www.GadgetOnline.com

White SR5

I second that, go with a wideband for tuning.

Zach

Jeff B. in Michigan

So with a narrow band O2 sensor if you were running lean at high rpm and temp the meter could show rich? It seems that is what I am reading into all of this.

I am very close to ordering the PLX unit. I plan to remove the stock O2 and run the narrow output of the M-200 to my ECU. I will need to add a resister between the stock O2 heater wires to trick the ECU into thinking there is a load on the heater circuit but otherwise I think it should work. With this configuration the unit would be in line and always reading the air / fuel ratio.

The only thing I need to confirm is that the local muffler shop can weld a bung (threaded flange) onto my exhaust pipe to change over the stock TOYOTA mount to accept the wideband sensor.

Gadget: Are you running your wide band all of the time? Did you have to get a bung welded into the pipe or is there some adapter available?

Gadget

The wide band O2 sensor is different then the stock one. It will not fit the same mounting hole. A new bung will have to be welded in.

I have been working with a company to try to develop a way to interface with the wide band sensors that come on the newer trucks. It would be nice to be able to read that sensor and know what the mix is doing and then to alter that signal to make the ECU do what we want as as far as mixture goes. The company is very interested, but they have a lot of other projects in the works and there is no telling when it will get done.

It would be nice to be able to remove the stock O2 sensor on the older trucks like mine and replace it with a wide band Toyota one that fits right in the stock mount and then use that wide band sensor for tuning and then alter it and send it along to the ECU so we can also make the ECU do what we want in closed loop mode.

The potential here is amazing as far as tuning goes and I want to do it now and not wait. I have been told I am to impatient at times...

So, if I had something like that now, would you be interested in buying one that will allow you to use the wide band for tuning feed back and then to also have complete control over the fuel mixture for tuning??????

My other projects have been completed and I should have them for sale soon. That is a rear O2 sensor simulator for those that want to remove their cats (for off road use of course) and a vehicle speed governor eliminator.

Gadget

www.GadgetOnline.com

03TundraTRD

Gadget
Do you know if my 03 Tundra has a wide band or narrow band o2 sensor. And would it be ueful with the APEXi S-AFC.

Gadget

The US 03 trucks do use wide band sensors. I do not have any idea what you have down there.

Gadget

www.GadgetOnline.com