O2 Sensor question

[solo_ryder]

Here's the story... I am asking this because my car lately has been feeling really slow and I am only getting 250km or less per tank (on 91-94 octane) in town, and abit more on the highway. I know that my front 02 is shot and not sure about the rear. I had a mazda hardcore mechanic pull some codes with some crazy code puller that plugged into the diagnostics and the only CEL that came up was the front O2... I am running a KL36 ECU BTW.

So my questions are :

Just how much performance do you lose with shot O2 sensor's? - lets not jump to the point on this one cause it's easy to say thats the issue but I do not know how much bad O2's can slow you down, I can imagine quite abit though.

Also, I tried to remove the front O2 off my headers and it will not budge at all, I am scared of stripping or breaking something on my headers so I have not attempted this to many times, I also tried when te headers where hot to no avail.

What O2's can I use? I know the answer will probably be the 2.5L probe ones, but will the 1.8L ones work considering I have a extra one here that I think is ok.

Where is the best deal to get these? I got qouted everywhere I go 160$ a side for probe NTK's and that is with the best discount I can get.

Thanks for the help. I need to start posting more questions again haha.

[hgallegos915]

The front one.. only way i could get it off was getting a plumbers wrench, getting wd40 and a torque bar. Took out the radiator and came out easily. You can use ebay ones but sometimes the connector is diff. Ypu can also use iniversal ones. It will impact fuel economy and power. bad o2 sensors i ran like a 15.5 goo ones like a 15.1. And sometimes they can be bad too and the ecu wont detect them because they work but dont give the correct readings but just enough to get it pass the ecu.

[solo_ryder]

Yea IIRC there was even a issue with the signal or something. I am not really interested in universal ones. I will have to decide if spending that kinda money is worth it, damn 4 wire O2's

[christexan]

These MX-3s don't run on gas, they don't listen to driver input, they operate 100% on sensors... as I was frustratingly explaining to my wife last night, a car used to run on gas, and if you gave it more gas, it needed more air, it would suck more air and fuel, and need more air, basically feeding itself so long as the air screw and fuel screw were anywhere in the ballpark....
Now the MX-3... push the gas pedal, the air intake port opens... and if the 36 sensors (not an actual number) under the hood all agree that actually letting fuel and air into the engine is a good idea, they will cooperate and let your car run.... if the air sensor on the air box (basically the air filter flow sensor) is unplugged... the car won't run (well, won't run above about 2500 with choppy idle, and will stall if you try to convince it there really is air coming in by pushing the gas pedal... if any other airflow sensors aren't functioning 100%, then you will get less than 100% commitment by the ECU... if all air sensors (including exhaust recirculation etc) are in agreement, that, yes, there is air.... then they'll pass the bill to the senate... the senate then decides "hmmm... okay, we have enough air, but do we think our taxpayers aka Crank angle sensors and cam angle sensor think this is a good idea???"... and if not, then they'll veto the bill and pass it back to the ECU which will then tell you the bad news via the Check Engine light messenger... if they all agree and pass the bill, then the fuel management chief executive ECU will decide if there is enough fuel pressure (aka back office kickbacks) to make it worth it's while to actually pressurize and open the injectors.... and that's how a bill becomes a law... I mean, that's how the MX-3 decides that if you, the voting public, REALLY demand to go, then they are in agreement that okay, this time will let you go, but 30 times a second they'll reconsider whether to continue this folly, and if ANY of these sensors disagree (not all accounted for above, there are lobbyists, committees, and goodness knows what else going on in the ECU), then they'll either say "Slow down" and get you home in limp mode while burning gobs of gas in the process (kinda like military spending), or they'll just say "we'll let you run enough to see the gasoline spraying all over your engine from the busted fuel line, or find the whistle from the split vacuum or intake line, but we ain't letting you leave your driveway till we see some graft in our pockets.

Did I mention I love working on my car and tracking down wayward sensors, hoses, splits, etc?

[RizzeRocket]

As far as i know the readings for 1.8 and 2.5 o2s are the same.
It will be really easy to pull out your o2 if you have a buddy with a torch.
Heat around the o2 sensor not the sensor itself but the pipe and it will come out real easy , sometimes it strips tho most of the time it wont.
If it does strip there are o2 sensor taps out there that you can buy Snap On sells it not cheap tho:(

[shrooms258]

XD +1 to christexan. laughed so hard at that

[mikeinaus]

my front o2 was dead a few weeks ago and i was having alot of misfires at low rpms and all around crappy performance. i got one from the wreckers from a mx6 i believe and it fixed the problem for the most part. still having a bit of misfiring but im thinking thats more related to my disty cap. i grabbed a spare one when i was there if you want to come by and give it a try jordo?

a few months back i bought some cheap universals off ebay and one of them didnt work, got a replacement and it also didnt work, went back to my original and it worked for a few months before finally kicking the bucket. if your going to go universal go with a proven brand. i remember reading somewhere in this forum about some universal ones someone recommended that might work for ya. id honestly go with the wreckers grabbing 10 or so at $5 a pop your probably more likely to come up with a few good ones then spending $40 per universal, or the $300 lordco wants for one...

p.s. what do you normally get a tank? i cant seem to push more then just over 300km (city) before my low fuel light comes on no matter how aggressive or economic i drive. which is weird cuz i usually never put in much more then 30L, but a few weeks ago i got almost 400km before the light came on and that took 38L to fill.. perhaps something is off with the low fuel sensor on my pump?

[Daninski]

Your fuel milage will be affected but no that much. Both the sensors on my MX-6 were shot and the only way I new was at the Clean Air station, I failed. Go to RockAuto.com they have pretty good prices, I've bought from them twice now and just order your MX-3 ones. Misfiring is a whole different question that can get a little involved so mikeinaus my suggestion is to Google the subject as there's a lot of interesting reading. You could start by changing your spark plugs but that's only one cause of misfiring and not usually the case.

Here's an excellant site for O2 sensors. http://ngksparkplugs.home.att.net/wsb/h ... html-.html" onclick="window.open(this.href);return false;

Misfiring. http://www.aa1car.com/library/misfire.htm" onclick="window.open(this.href);return false;