I found this in the FAQ...doing my research like a good little FD newbie.

originally posted by jimlab:
8) While it isn't 100% accurate (since nothing but a multi-wire heated wide-band 02 sensor is truly accurate, but at high cost), you can monitor your oxygen sensor voltage to give you an indication of how rich (or lean) your engine is running. Anything below 0.86 volts is getting very lean, and if your readings are in the 0.82-0.84 volt range, you need to back your boost level off until you get adequate fuel. Anything from 0.80 and lower is almost guarantee to lead to engine replacement. 0.90 and higher is fairly rich. There are many manufacturers of Air/Fuel ratio gauges to monitor this reading, or you can (with a little work) hook up a multimeter to the wire lead at the ECU, which works for temporary measurement.


How do you know which wire lead it is at the ECU? Anyone have a wiring diagram? One that is in some-what of lammens terms? I am pretty good at wiring diagrams so it can get a little crazy, but on the same note, I don't want someone to post something that looks like a plate of spaghetti....mmmm....spaghetti. Anyways, thanks for the help.


Mike

 

On second though...how is "it" (air/fuel ratio) even adjustable with a stock ECU?

 

Don't bother, you can't measure AFRs on a narrow band O2 sensor -at least not to the degree of precision needed to keep a rotary from popping.

 

Can you explain the narrow band/broad band O2 sensor theory? What's the difference? And you can't even do it with the multimeter at the ECU as Jimlab had posted?

 

http://www.jaxracing.com/widebando2/ Go to the FAQ. Basic information, but a good starting point.

 

And the wiring diagram is in the FSM download thread stickied at the top.

Dave

 

Narrow band O2 sensor output is 0 to 1 volt (used in 99.9% of cars)

Wide band O2 sensor output is 0 to 5 volts (limited to a couple of Hondas & all air/fuel monitor systems used for turning)

You can do a Google search & read all about it.

 

A major difference is that a narrow-band sensor changes voltage very quickly as the flow passes stoich, and a wideband sensor is much more progressive.

Kind of like the difference between a thermoswitch and a thermosensor.

Dave