Exhaust Manifold and 02 Sensor help!

[JustinGB]

First, I just found out that I have a 94 California model, due to having two pre-cat oxygen sensors. Now my question is, is there a way to get rid of the subsecondary oxygen sensor and have the car running just as good? I have to replace them because I feel like performance in the car is very poor and hte 02 sensors may be bad.

Also, I bought some headers/pre-cat on ebay and the problem I have is that it doesn't really have prewelded spots for the oxygen sensor. Now can anyone suggest what places (nyc/staten island) or what I can do to make the 02 sensors fit?

I got these type of headers


but have these kind of adapter plates/mounting plate for the 02 sensors:


Any help would be very well appreciated.

Thanks very much!

[JustinGB]

anyone?

[toyomoho]

If an I4, all engines have two sensors. California cars would most likely use A/F sensors in place of the 02 sensors. The ECU monitors CAT performance by having one sensor before and one after the CAT.

A custom exhaust shop could weld the sensor brackets on if they had the fittings.

You can purchase sensor simulators (do a Google search) that replace the sensor and keep the ECU from triggering a trouble code. One issue is legality, removing the sensors will cause the car to fail any visual emission test.

[Flashmn]

California cars would most likely use A/F sensors in place of the 02 sensors.

A/F sensor is exactly the same as an O2 sensor.

[toyomoho]

A/F usually refers to a wide band sensor, 02 a narrow band.

[Flashmn]

Naah man, You state if you have a wideband, UEGO is usually what they call the wideband, A/F and O2 sensors are 100% the same.

[Donald]

That looks like the same headder I have on my '92.
Yeah, it only has a mount boss for one O2 sensor, and it should have an adaptor plate to take a screw in sensor.
There are aparently two types of sensors used on the Corollas, a bolt on (with a flange and two holes), and a screw in type. Some of the aftermarket sensors come as a screw in type with the adaptor plate so in can be mounted either way.

If there is a way to run only one sensor, then you are OK. If not, I think you will have to thak the headder to a muffler shop and have them make a mounting boss for you.

Mine was supposed to fit a '92, but it was too short to bolt up to the CAT. I had to have it lengthened.

Good luck.

[JustinGB]

These are the kind of replies i've been looking for!!! Thanks a lot guys, I think i'll go shopping for 02 sensors that do have the screw in type and just let a muffler shop deal with the second 02 sensor. Thanks a lot!

[JustinGB]

One more thing, can someone also confirm this for me, is the size of the shoulder bolt that holds the exhaust manifold into the engine m10x1.25? I need to helicoil one of the holes because it got stripped. Thank you.

[Flashmn]

Yes, that would be the size.

[Bitter]

search the internet about how to use spark plug anitfoulers to trick the post cat sensor into normal readings, that'll get rid of the check engine like you'll get.

[Flashmn]

it wont help if theres no O2 sensor there. doooh...

[Bitter]

Originally Posted by Flashmn

it wont help if theres no O2 sensor there. doooh...

he'll obviously have to get it bunged in, the electrical sims if not done correctly can cost you a new PCM. the ant-fouler trick works on a wide range of cars, obd1 and obd2, from a 5sfe celica to a 6g72 eclipse.

[Flashmn]

Why not just have the secondary O2 sensor installed in after the cat. I mean sheesh its not gonna even cost much to do.

[JustinGB]

i'm not sure what you guys are talking about... but to make things clear I have two 02 sensors PRE-cat. I have one righ ton the exhaust manifold and one right before the cat converter. So I don't believe i'll really get any CELs because they're both precat and nothing should change as far as air/fuel mixture except for airflow.

Thanks a lot... i'm going to do this soon i'll keep you all updated!