Rx8manRich

So my front o2 sensor went bad.. I ordered a part from a local auto parts store, and specifically said UPSTREAM MT FRONT O2 SENSOR. The guy said that he had on in stock (which seemed odd to me because I called 5 other places and they said because its a special part it has to be ordered.) needless to say I went and got it anyway. i installed it, started the car, and wallah, she ran like a piece of hot poop. About 10 minutes into Rough idleing at around 600-800rpm, it threw a CEL. The codes were as follows:

P0030 Front HO2S heater control circuit problem ON 2 HO2S heater ´
(See DTC P0030 )
P0031 Front HO2S heater control circuit low ON 2 HO2S heater ´
(See DTC P0031 )

I at this point figured it had something to do with the o2 sensor (as i literally was running the car 5 hours before that and she ran like a olympic champion.) In a attempt to let the computer systems adjust themself to the new o2 sensor (or so i thought from another rx8 forums) i drove it around hard for about 5-6 minutes.

I found out later that night of long pondering on what the issue could be that the o2 sensor was actually a rear o2 sensor, not a front o2 sensor.

My question is could this cause long term damage to my car for a less than 5 mile drive using a rear o2 sensor on the front. Other than the things that were happening immediatly, like extremely rough idle's and stuff. This part has been replaced with the right part and i will be running the car later today to see how it goes.

Thanks,

RX8Soldier

iTrader: (24)

no need to worry about long term damage. Just, don't start driving around with it.

Now, could you please stop creating new threads on topics already discussed? And, learn to use the search feature. It will improve your knowledge far greater than just asking.

Rx8manRich

I am trying, i'm sorry. I appreciate you not being a dick about it though!

Would that sensor being the wrong one cause it to run like complete ****?

RX8Soldier

iTrader: (24)

Yes, the front O2 sensor is needed to make the car run. The rear sensor is more for emissions purposes

dannobre

iTrader: (3)

The car will run with no front O2...it just runs in open loop all the time

RX8Soldier

iTrader: (24)

^I meant "run properly" lol

Rx8manRich

Will it cause it to rough idle and stall, Will it also potentially throw a p0420 code if the front o2 sensor was bad?

nycgps

iTrader: (1)

the rear sensor is completely different than the front. well, it looks the same but it's really different.

don't think it will damage your car, but if it's the wrong sensor. bring it back ask for a refund.

and order these 2

Front

Rear


Replace it, Done.

Car will run without Front O2 sensor, but it will run like dannorbre said, all open loop mode.

think of it this way, you can type really really well, couple hundred words per minute, NO PROBLEM!

so even when you are blindfolded, you should be able to type, right? keyboard layout is always the same. so you start typing

but you wouldn't know what you did wrong if you are blindfolded, right ? yea you got a few random errors here and there. but you will still be able to type 100 pages out.

That's how open loop mode works, it uses a pre-define table for fuel/air ratio, it will work, but not optimal.

take your blindfold away, ahh, you see everything, you know what your mistakes were, said "wtf", and correct them.

That's how closed loop mode works, after a period of time, based on the Front O2 sensor feedback, the ECU will know what's right/wrong based on a pre-set ratio, will automatically enrich/lean out the mixture on it's own on the fly.

what I'm trying to say is, your car won't blow up or die because the front O2 sensor is missing, but for light throttle and some operation it's better to have it.

Rx8manRich

hey nygp thanks for the responce, i did better than that, i just ordered both front and rear from mazda to be certain cost me over 550$... but thats a whole nother story. i am replacing both but the original reasoning for replacing the front o2 is because i was throwing a p0420 code.. i just replaced the rear sensor less than a year ago.. when i removed the cat because i was going to replace it, it was flawless. and i mean FLAWLESS. you could see the mesh basically perfectly and untouched. So at that point i figured... well it must be the front o2 sensor. Will the front o2 sensor trigger a p0420 code... so that i

nycgps

iTrader: (1)

ouch, 550? you should have get them from Mazmart. He can beat ANY dealership prices.

anyway, well, sometimes the CEL for part A does not mean it's part A that's malfunction.

I got this System run lean CEL a while ago, it turns out to be my MAF malfunctioning and it's a brand new MAF. no code whatsoever from it, I even check the MAF sensor itself and it's all within spec.

swap the old MAF sensor back (lucky I didn't throw it away), everything back to normal.

Rx8manRich

I'm sorry and i thank you again for your timely responce, and edit. i enjoy reading these things and you are all very helpfull.

But i did not understand what u mean.

So a malfuntion for a cat aka p0420 could be either front o2 sensor, rear, o2 sesor, or cat? aka part a would be the original reason for the code but it may not alwyas be that specific part?

nycgps

iTrader: (1)

P0420, most of the time is cause by a bad CAT. but it could be a failed rear O2 sensor. or it could be a failed front O2 sensor that gives false readings to the ECU, then when it compare the values to the rear O2 will trigger this CEL.

it can cause by exhaust leaks too.

but again, most of the time is caused by a bad CAT.

oh, u can read this site, it can gives u a better understanding.

http://www.obd-codes.com/p0420

AshTRX8

hi sorry for starting an old thread, new member cant start a post for 30 days, plus pics/research on threads so far are not really clear and have confused further

can someone please tell me how to access the front o2 sensor. "i know its on the upper intake manifold", but cant visually locate it on my car, many thanks

dannobre

iTrader: (3)

Front O2 is on the exhaust manifold....just ahead of where the CAT and exhaust meet. It unplugs on top of the motor just midline near the clutch slave and the oil filter

AshTRX8

Many thanks Dannobre, but I still can't find it, would it be possible to send an image of the sensor point on from a non dismantled engine/manifold. Also if I have got it right, it should be pretty easy to remove once I am able to locate it. Many thanks in advance

dannobre

iTrader: (3)

https://www.rx8club.com/series-i-tec...sensor-208513/

Post # 10 has a picture of a manifold with the sensor in it