O2 Sensors, How do i know when they are bad? Options

[sapperk]

Any one know how i can tell if my O2 sensors are bad? My car idles like crap at low speeds, and jerks. I tried almost every other thing and according to troule shooting its the O2 sensors. But they are expensive, so does anyone know?

Also are both O2 sensors the same. Top and bottom?

[LewFX]

try resetting ecu first and if it still jerks around, replace em. celicas are known for bad o2 sensors

[sapperk]

Both O2 sensors, are they the same type?

[Punch]

all toyota have that problem. If your check light is on get it looked at...

[BlackSTX]

I doubt your O2 sensors make your car act that bad. Mine were bad and the only reason I knew was that my CEL was on. My car still ran perfect even with it on. Sounds more like you need a tune-up.

[Skate4mindgame]

Yeah id suggest getting them checked out, but BlackSTX sounds about right it sounds like you need a tune up

[exxtractor]

Both O2 sensors are NOT the same. One is 1-wire and the other is 2-wire. There is also a huge cost difference between the two, around $50.

[erics1one]

A big decrease in mpg is normally a pretty clear indicator. If the sensor is malfunctioning (but not broken) it probably won't throw a CEL.

I would:

reset your ECU:
http://www.6gc.net/index.php?action=howto&itu=33

then check your mpg

[dustin15brown]

arent o2sensors pretty expensive?

[erics1one]

You can buy the generic sensor for cheaper and splice the wires with your old connector.

[BLADDER_MASTER]

Seems like I was going through the same issues. The idle was hella crappy. It would fluctuate from 800-1000rpm when the engine was cold. Then after a long period of driving (About 2 hours), I couldn't floor it. 1. because when I would floor it, the car felt like it clutch-kicked itself (when I didn't) and the mofo would jerk hella. 2. because after i got past that "clutch-kicking" phase, I would go towards redline and the mofo had trouble getting there. It would struggle to reach 7kRPM to the point where it wouldn't reach it (Super ghey). In the end I changed the O2 sensor to a Bosch Universal O2 Sensor and it fixed the problem. No more crappy idle (ghey), engine clutch-kicking itself when floored (super ghey), and no more struggle to reach 7kRPM (ultra ghey). I almost bought the OEM type which was about $100 more, but after I found out that the Universal type works the same, I said "SCREW YOU!!" to the OEM type. But to clarify I got a 3S-GE (4-wire O2 Sensor) unlike your 5S-FE (1-wire O2 Sensor). So I don't know if my solution will work for you as well.

This post has been edited by BLADDER_MASTER: May 20, 2005 - 3:30 PM

[sapperk]

I changed the spark plugs and stuff last week, wires too. That wasnt it. I know im do for a timming belt, and fuel filter, maybe that can be it.

[juBz86]

how many wires is the rear sensor on a 95 gt??? and i would need to lift the car to get to it right??

[CelicaQT]

arent o2sensors pretty expensive?
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O2 sensors at the dealer are going to run you around $170ish i think. I believe that's how much it costs.

Had to get mine replaced a few months back. My check engine light kept going on and off for the past 2 yrs at random, I finally had enough and got it fixed.

[erics1one]

how many wires is the rear sensor on a 95 gt??? and i would need to lift the car to get to it right??
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I'm pretty sure they both have two wires....

[juBz86]

i saw the one in the front and i remember it having only 1 wire.

[erics1one]

Might be different with OBDI.

Im '96 and OBDII.

[juBz86]

can i buy 2 universal bosch's??

[BLADDER_MASTER]

can i buy 2 universal bosch's??
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I don't see why not. As I stated earlier I bought a Bosch Universal O2 sensor and my car is running fine.

[juBz86]

ok so i replace the o2 sensor in the exhaust manifold with a bosch universal one because they said it was only one that came up on their computers at pepboys. i checked the haynes manual and it only shows one o2 sensor being replaced. wtf!!?!?!

and the check engine sign still came on!!!!! is it supposed to happen? i ended up disconnecting the battery and i'll see if there is an improvement in gas mileage.


edit:
the code that came up when i got it checked was 27. and the book says its the sub-oxygen sensor - open or short circuit. that sensor is only for cali. my car wasnt from cali and i just looked to make sure i didnt have one.

This post has been edited by juBz86: May 25, 2005 - 5:56 PM