Bad Air/ Fuel mixture sensor warning for ALL Yaris owners

[TheSilkySmooth]

Originally Posted by Return of the Yarii

I have an 07 Sedan and mine was crossthreaded, found out when I did DC header install, bought a new one from Ken @ Sparks. Its listed in the classifieds along w/the header.

It is indeed an Air/Fuel Sensor, the O2 sensor is downstream

*pending sale of A/F Sensor to member on the board*

The is all just a matter of semantics but these sensors conduct OXYGEN at various mixtures outputting a voltage in response to the mixture, so the sensor ONLY senses oxygen but the EC can calculate the mixture using E and a couple other variables for cross check. There is no FUEL sensor on a car per se. You have the MAF that indirectly "supposes" air flow through the "cooling" effect of ambient air running over a hot wire "conductor" or foil and adjust voltage across to run in stasis, and MAP that supposes "throttle position" by the reading absolute pressure in the intake manifold typically with a mechanical device sim to a "barometer". Toyota service parts can call it what they want, but the engineers that design it call it a wide band o2 sensor that looks at free oxygen in the pre-catalysis effluent stream. So maybe we call it #1?

[TheSilkySmooth]

And NOW, to put me in the running for the big dick head award: The auto repair industry recognises MIL* for what we've been calling a CEL. I know this is "Down wid teh MANg Age" but very soon if not now NO ONE will know what anybody is talking about if we all make up our own terms for stuff and do not use the proper term.

*MIL = malfunction indicator lamp

White Cholera Woiker

[eric81]

The Silky Smooth is far too smart to be from earth. We have aliens. Anyone got any Raid? Anyone? And what exactly does that mean anyways? The Silky Smooth... what is so silky smooth? I don't understand?

Still, crossthreaded A?F sensors suck, and they keep us from being able to use our aftermarket parts without replacing a bunch of other stuff. I also recommend checking the little silver bolts on the top of your engine that hold the spark plugs in place (they are black, have one bolt in them, and there are four of them across the top of the engine) to see if their bolts are as bad as mine were. They used a cheap bolt on mine and I snapped it in half trying to put it back in place. I took a different one out to measure it at the hardware store, and it was all stretched and warped too. So I replaced them all, and they were all bad. Toyota sure did save those pennies when it came to our cars.

[TheSilkySmooth]

I am the silky smooth brother , not the silky smooth.

I wouldn't think the factory would cross thread the sensor - maybe it was fused to the bung on purpose? Does any tech on here know if the header sensor comes together as one part#?

This is all basic stuff if you are a tech or read tuner mags and forums a lot. Gotta get out there and Ed-U-Kate yosef

[TheSilkySmooth]

Thread Hijack
Any one pulling off the headers - can you tell if there is a double-wall exhaust pipe to keep the exhaust super hot into catalyst #2? I wonder if this is what they replace on the TSB at Toyota Service if you complain about exhaust smell coming in the car. If I take the car after my Papa drives it and wail on it getting on the Interstate rt93 I smell stinky sulfur and gunpowder smell in the car. I am guessing if the inner exhaust pipe is melting and closing down and exhaust is leajking oout after the end of the first catalytic converter?

[TheSilkySmooth]

Originally Posted by eric81

The Silky Smooth is far too smart to be from earth. We have aliens. Anyone got any Raid? Anyone? And what exactly does that mean anyways? The Silky Smooth... what is so silky smooth? I don't understand?

Still, crossthreaded A?F sensors suck, and they keep us from being able to use our aftermarket parts without replacing a bunch of other stuff. I also recommend checking the little silver bolts on the top of your engine that hold the spark plugs in place (they are black, have one bolt in them, and there are four of them across the top of the engine) to see if their bolts are as bad as mine were. They used a cheap bolt on mine and I snapped it in half trying to put it back in place. I took a different one out to measure it at the hardware store, and it was all stretched and warped too. So I replaced them all, and they were all bad. Toyota sure did save those pennies when it came to our cars.

This is typical Asian practice, see it a lot on street bikes - its called "torque to Yield" the bolt is not reusable and permanently strained out of shape. It keeps the fasteners from coming loose. Unlike GM whom has all kind of problems with "oversized" bolts coming loose on intake manifolds because they are under-torqued and back off over time. SAves on washers also which are a bitch to handle in assembly lines.

[Black Yaris]

Originally Posted by cali yaris

Correct, and it's a very unusual 0-5v sensor, made by Denso for Toyota OEM. No one else makes it, and you have to get it from Toyota (or a salvage yard )

The rear one, between the cats, is an O2, however.

My header install went fine -- no cross-threading and no CEL's.

We sell Denso at AutoZone

[Shroomster]

Originally Posted by Black Yaris

We sell Denso at AutoZone

*cough* you apparently don't sell the door edge protectors at least to me from your store...pre hack

[SEVEN]

Ok so if I change my header I have to get a new a/f mixture sensor (it's a megan header)??

[TheSilkySmooth]

Originally Posted by SEVEN

Ok so if I change my header I have to get a new a/f mixture sensor (it's a megan header)??

NO, you just have to remove the old one CAREFULLY - I would read the Factory toyota maintenance manual ( on here in PDF somewhere) and double check the procedure for R&R-ing the #1 O2 sensor.

[eric81]

Hope the original is not cross threaded. Good luck!

[GeneW]

Originally Posted by eric81

From my understanding, many a people have thrown pistons that way. But our cars are pretty low on the power, so you are probably right. Still, it was pretty bad in my engine. And it smoked BAD when I put the new plugs in. It is all nice now. I will check the plugs in about 2 or 3 more tanks. I will also post a pic of one of the bad plugs here tomorrow sometime. It is WAY burnt up. All black and stuff. My neighbor even felt bad for me.

Black plugs aren't a big deal, unless they're oily. When you run so rich that the gas fumes dissolve the oil on the piston walls then it's a bad time. You gotta really really run rich to do that....

Now if you run super lean.... omg is that tough on the exhaust valves! I had a 73 Chevy Nova that had an orange glow under it from the exhaust manifolds glowing orange because of a lean mixture.

Gene

[eric81]

The exhaust manifold was getting hot enough to cause me discomfort in the cabin of the car. It was a very hot running engine for a while there. But, it is all better now because I got a new A/F sensor. It is all normal again.

[auxmike]

Has anyone swapped out their o2 sensors since this thread started? Anymore crossthreading issues?