How Can I Tell If My Oxygen Sensor Is Bad?

 

If it stays out late and brings home bad grades?

 

If it's the original one it's probably long past it's use-by date. Get a new generic one, they're cheap.

 

buy a direct denso replacement they are great sensors and work very well thats the only thing I will put in my cars... bosch sensors SUCK!!! and universals will not be 100% honed into yoru car so it wont run 100% as well as it should!

 

Honed into your car? What a load of...

0-1V narrow-band sensors all work exactly the same way. No "honing" is required.

 

I have had a bosch sensor for quite some time with no problems. I just installed a narrowband, so I'll see if it really is working weel as soon as my car is running again (hopefully in the next week.)

 

we covered this before the same universal o2 for a rxy will work in about 150 other vehicles from chevy, to dodge, to foriegn to what ever
they are not calibrated for CORRECT reading on the car.. spend an extra 10.00 and buy a direct fit

 

i'll tell you what:

somebody use a separate wideband to datalog AFR's under closed-loop in a car with a Bosch universal O2 and then swap in whatever you think is better. Then prove to us that the car has less overall error (deviation from stoichometric) with the supposedly superior o2 sensor

 

I have.... and the bosch uni will read 1-2 bars different under light load and 2-3 bars different under wot....

I had this problem years ago when tuning a car I kept getting knock when I should'nt so I went to the store changed out my uni that had 4 miles on it and put in a direct fit for the car (from bosch uni to denso direct fit) and I found my low spot and was able to fix the problem... they do not read 100% acurate...

universal items universally fit nothing. for the extra 10.00 ALWAYS buy the direct fit its the only way to go.

I have been in the parts busines for many years and before that was a ASE certified mechanic for 6 years... I would not stray anyone wrong. I've got better things to do then that...

will the uni work .. yes but will it not be accurate and could possibly lead to probles YES ESPECIALLY in highly modded turbo cars were tuning is #1

Dave

 

here is a link to show how many cars the bosch universal oxy for our car will fit...

after this
https://www.rx7club.com/showthread.p...+oxygen+sensor

/thread

 

Generic oxygen sensors are not calibrated for any car specifically. They all provide the same readings.

 

Mine is disconnected because the wire broke. I can't tell any damn difference to how it runs.

 

same here. I don't know if i'm running rich or lean or what.

 

You really think a narrow-band sensor should be used for tuning a highly modded turbo? Jeepers...

Nor should you. The only difference it’ll make is that you'll run a little richer during cruise than you would with a functioning sensor, and your emissions will be worse as a result. Put a new one in and save a little gas.

 

if your car runs the same unplugged as it did plugged in then the sensor is bad.

 

Bollocks, like I said you won't actually notice if it's working unless you measure fuel consumption, cruise AFR or emissions.

 

i just installed 2 a/f gauges, and they both give me the same readout, LEAN!! regardless of how much fuel i add to with my SAFC i still get the same reading, when i disconnect my o2 readout i get RICH! could this be due to a bad O2 sensor? or did i tap into the wrong wire at the ecu? Btw, its an s4 and i tapped into the black wire pin 2d? thanks

 

Ow... my brain hurts from reading this thread already. I'm obviously in the wrong line of work - I should be taking universal components, reboxing them with boxes that have a picture of a specific car on them, and selling them for $20 more.

To address several points (some behaviors may be specific to the S4s, but I don't think the S5 is much different):

How do I know if my O2 sensor is bad?
Do you know when it was last replaced? Was that under 80k miles ago? If not, replace it. They get lazy LONG before they quit entirely, and a lazy O2 sensor will affect mileage to some extent but won't trigger the ECU's "Hey, this thing's bad!" circuit until it fails completely. Just replace it, they're cheap enough.

My car runs the same without it as with it.
For a 2nd gen, that's about right. The range of operating conditions that the ECU uses closed loop for is pretty small - below 3500 RPM, light throttle, when warmed up. I've spent far too many miles on the highway with an O2 sensor check light attached, and it's very easy to get it out of closed loop mode.

My O2 sensor [went bad/was the wrong part/etc], and I detonated under boost.
Go look for another problem. The ECU pays zero attention to the O2 sensor when you're making any decent power. It runs in open loop mode if you're anywhere near wide open throttle or boost, or any time you're over 3500 RPM.

The narrowband O2 sensor needs to be matched to the car.
This may be true for newer vehicles that use wideband O2 sensors, and it may be true for a wideband O2 sensor controller, but NOT for a narrowband O2 sensor. The model-specific ones come with a connector that plugs into your engine harness instead of requiring you to solder wires together. That's IT. A narrowband O2 sensor has one job: Report to the ECU if the exhaust is rich or lean of 14.7:1. It has a small linear band right around 14.7:1, but behavior in this band is highly dependent on temperature, age, etc, and I know for sure that the RX-7 ECU pays no attention to that - 0.5v is the threshold point, and all it cares about is rich or lean of that point. If your O2 sensor is cycling around something other than 14.7:1, it's bad. Simple.

If anyone's interested in more info about the ECU and O2 sensor, I'd be glad to provide some, but please... intelligent questions.

-=Russ=-

 

i think it needs to be replaced.... but would my guages read lean if its bad? or are the gauges not working properly?

 

It's sooooooooo darn easy to figure out if the 02 sensor is inputing to the ECU.

There's a six socket, green check connector in the engine bay near the Lead coil area. You buy two cheap LED's from RadioShack and install them in the middle two holes on the six socket connector. One wire of the LED to the BW wire and the other to the Yellow wire. Make the two wires long enough to reach the wiper area and tie them on.

Go for a cruise on the hwy at a steady speed and watch the light. A constant flashing means closed loop, Anything else is not closed loop. Can't be in closed loop without the 02 working.

And yes, you can run the same wires from the ECU plug, but I'm talking quick and dirty and temporary. Certainly temporary if you hit the wiper switch.

The plug and socket are shown here: http://www.teamfc3s.org/info/article...odes/main.html

Sockets ABR and GL are the ones I mentioned above.