dude o2 is like 150 ish not bad evey 2 years and its not because of you cat, its you header down pipe because its father from the engine??? so just gut a cat for after smog you clown mike hahaha

 

If your CEL is on do you fail the emissions test even if it passes the visual test and sniffs clean? Assuming the intermittant CEL won't fubar the test, they do make O2 simulators to generate the resistance required to placate the ECU. I have not tried one of these so don't take my word for it, but they are supposed to cure CEL's. It would be easy to swap that out prior to your emissions test, then reinstall it.

http://www.amazon.com/Magnum-Adjusta.../dp/B001CZOQKM

 

I believe in Cali as here they have mobile smog trucks that have cameras that can tell if the cat is working right or not. Once AirCare is done in 2011 we will be seeing a bunch more I think (in BC).

To the OP if you put in a high flow cat you will still pass smog and also free up a bit of the bottleneck you have in the stock cat. If you do not, just leave it in and enjoy the sound of the truck as is. Getting rid if the cat and straight piping is pointless I would rather lose 2-3hp and have it then have that power and be doing my part to ruin our environment.

91_TOYOTA_4x4 call Toyota and see what a new O2 is going to cost you...bet its a lot more than $150.

 

if the CEL is on I will fail emissions test no matter what. they wont even look at the vehicle, as it is the first.

 

well i had a new o2 put in and it was 180...

 

Somebody correct me if I am wrong, but isn't the ECU looking for some range of resistance from the O2 sensor? i.e. If the resistance is within the desired range, the CEL stays off. If that is correct, couldn't you add a resistor between the O2 sensor and the ECU in some 'discreet' location to keep the CEL off?



EDIT: Jay, ... ahh yes grasshopper, now I more fully understand... thanks for the education.

 

The engine uses the input from the o2 sensor to figure out what fuel adjustments it needs to make. If you throw a resister inline to the ecu then it will get false info.

If its bad, replace it?

 

My $100 SS magnaflow has passed the smog tests going on three years so far..

 

Mak - What is the numeric code you are getting? If pre-cat 02, have you checked to see if the continuity is good? Maybe there is a poor contact which would make it intermittent. Maybe its just plain dirty due to carbon build up. Opening your engine a bit more with your headers may have sped this process. If you're short on cash, you could try cleaning the O2 sensor with a product called deep creep which is made by sea foam. I've read this has worked on O2 sensors with limited success, however cleaning an O2 sensor in any way shape or form is usually last resort. Replacement is likely the best option.

For the record my 92 has only the pre-cat however with intake, headers, glass-pack/exhaust I am flowing pretty good and have not yet blown any codes related to O2.

Hope this helps,
Ben

 

honestly, I have NO history of my truck EVER being tuned. i bought it at 107k miles and I seriously think it has only had its timing belt changed either never or once. ( it just broke 143 now ) the o2 could be preplaced and that might help it. but it never came on until I did the headers.

 

No $h!+.. bummer dude. Do you plan on doing the work yourself? If so, take some pics. I think the timing belts are recommended every 60K or so. Mine isn't due but, I plan to change it anyway before winter (October) when I do most of the seals. I'm very confident you can take this on yourself if you did your own headers.

 

lol my check engine light just came on last night uhhhhhhh frickin toyota's man

 

I've been reading this thread , getting part number's and such , getting ready to put header's on my 94 4runner. Came up with a different part number than what was posted. New number for the header's I found is THY-505 , from www.dougthorleyheaders.com .. so going to look for gasket set right now .

 

LDL: I can get ya a way better deal than you will get from their website. and yes, thy-505 is the same kit i got. long tube headers. the kit comes with the 3 gaskets you will need. if you want the phone number to save ya at least $100 lemme know!

 

Calipatent : Sure , everyone is alway's looking to save some cash, just post it up , or email or private message me : txharley10@hotmail.com

 

While you're building ideas of your header/exhaust systems - make sure you take a look at VHT FlameProofing. It's great stuff to use BEFORE installing.

 

update: the CEL light has not been coming on ever since the weather has been 80+ degrees. lol

 

lol good news dude same with mine, we just had a few hot days and my truck ran so good when it was hot, even though my afm in done lol toyotas must love being cooked

 

got Downey headers from ebay (original co-owner sells on there) and rebuilt the 3vze, got tons of time in it but little money so i'm trying to do it all when stuff is easier to get to. Got the Heads and lower intake on and about to install the headers, then belts, upper intake, new Optima battery, new cables, new stereo, new spkrs, blah blah blah. Thanks for the helpful info and links.

 

Brhesson,

How much did you pay off the bay? ceramic? Take a picture of what you went with. I'm anxious for you to see how things turns out. Thats badass.