U of Dayton-FC3S

So the guy who previously owned the rx7 which is now mine had disconnected the O2 sensor when I discovered this a few days ago I was talking to him about it and he said that it helps it from running too rich and you get more power. I thought the O2 sensor helped keep the A/F ratio in check and wouldn't removing it or disconnecting the O2 sensor cause the computer to go into some sort of limp mode for it or possibly make the A/F too rich. Any input would be helpful I'm trying to decide whether to reconnect it or not, but I want to make sure of the benefits or problems. Thanks in advance. Oh by the way its a 88 N/A.

MRX_Rotary

With no reading from the oxygen sensor, the ECU uses a default map which is richer than when the sensor is plugged in. You'll see a difference of a couple MPG when you reconnect it, if the sensor is still good.

U of Dayton-FC3S

will that running richer cause a loss of power and also maybe fouling since it may not be burning all the way?

Optics

Defanitly

cbrinega

The O2 sensor only affects closed loop operation (when the engine has been in a steady state with mild to low throttle for a reasonable amount of time). I recommend using the O2 sensor. Do you have any mods or goals for the car?

cbrinega

Sorry, I should have said this too:

The O2 sensor is used to lean out the fuel mixture under cruise conditions, so the car will be running rich on the highway or in town at constant speeds if the O2 sensor is disconnected.

Most N/As run too rich under acceleration anyway (even with a working O2 sensor), but the O2 sensor isn't the cause. The ECU's fuel map is the culprit.

U of Dayton-FC3S

Yea I was afraid of it running even richer since they naturally run rich. Would I be able to lean it out with a SAFC and a guage or do I need to get a standalone to get it to really work. Im looking at pretty much all the bolt on mods and removing the PS and getting my 5/6th ports working well. I am going to eventually swap my car back to a T2 the previous owner just swapped a na in instead of doing another turbo engine . Thanks for the info guys it was very helpful.

U of Dayton-FC3S

I just noticed you live in Dayton Ohio thats where I live in Centerville, I don't see many other rotaries around.

U of Dayton-FC3S

I think the wire has either gone up inside the harness thingy or it was cut. If i run a wire from the O2 sensor directly through the firewall and to the control unit, the connection is D2 for the S4 I believe will this work just the same or is there a relay inbetween?

WonkoTheSane

iTrader: (2)

Its a direct connection.. Nothing in between. I can't tell you what connection it to the ECU, though.. It looks like you might have it, but double check with the FSM before connecting anything

NZConvertible

He is wrong. You will get absolutely no more power from running without it. It is only used during ligh-load cruising. As soon as you put your foot down the ECU ignores it.

It will not cause any problems at all. The only difference will be a slight increase in average fuel consumption and higher emissions. But there's no good reason to to leave it disconnected.

slpin

iTrader: (9)

you might be able to save a few ounces if you remove the O2... other than that... dont remove it... buy a new one instead, you might get better mpg!