oxygen sensor

warrior · Post by **warrior** » Sun May 19, 2013 6:47 pm

I have just bought another mx5 today, it is fairly standard except for an aftermarket headers exhaust etc. I have just noticed the oxygen sensor is just sitting in the engine bay as I am guessing there was nowhere in the headers for it to go? I will get an exhaust shop to fit it.

The cars runs very well but my question is what will this be doing to the car? Running rich? running lean? Down on power? Using to much fuel?

SLYDIT · Post by **SLYDIT** » Sun May 19, 2013 7:00 pm

yes it will be running rich and youll have idle issues. my suggestion is to get a bung welded in down at the collector and upgrade to a heated o2 sensor. your car will run MUCH MUCH better for it.
Trust me on this one. i did a fair bit of data logging the 02 sensor on my car and at the lights it would cool down too much and lose the signal.
also a NA mx5 runs off the 02 sensor ALL THE TIME except for two occasions-cold start and full throttle above 4500rpm.
yes thats right.....even at full throttle the car is running off the 02 sensor right up to about 4500 or so rpm.

eated o2 all the way!

authentic · Post by **authentic** » Sun May 19, 2013 11:12 pm

Is a heated still all good to run with a 'normal' o2 sensor location?

i.e.

WideOpenThrottle · Post by **WideOpenThrottle** » Mon May 20, 2013 8:20 am

Dont see why not but wouldn't it be more accurate if it were measuring at or after your bulb so that it is reading a combination of all the headers rather than just the one as in your case?

authentic · Post by **authentic** » Mon May 20, 2013 11:23 am

I suppose it would be. Mine came like this from Japan, where as most come with the bung after the collector(s). Else I would have been running a heated o2 already.

Timmo · Post by **Timmo** » Mon May 20, 2013 12:33 pm

It's probably there so the sensor doesn't need wire added to it to extend it down further.

SLYDIT · Post by **SLYDIT** » Mon May 20, 2013 6:33 pm

yours will be fine there authentic.
it only when adding a bung down by the gearbox or when running a turbo that a heated one is a must

authentic · Post by **authentic** » Mon May 20, 2013 6:45 pm

Sweet. So no 'gains' from running a heated over a standard one if the location is fine for a standard o2 sensor?

warrior · Post by **warrior** » Mon May 20, 2013 7:13 pm

I have a supercharged car with aftermarket exhaust and had to run a heated sensor because of the location of the bung. This car I have bough also has an aftermarket exhaust and may need a heated sensor also.

There is no performance gain from a heated sensor to a standard one.

SLYDIT · Post by **SLYDIT** » Mon May 20, 2013 7:13 pm

you may get slightly better running and certainly if you do short trips it will help, but other than that not really. you just have to keep the sensor in its correct operating temperature and it gets tto cold down by the gearbox and goes dead at idle and sometimes even cruise.

oxygen sensor

oxygen sensor

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