OBDII catalytic converter code? LSD whining noise? ST sway bar endlink?

[az_240]

Was just cruisin along when my cel comes on so I go to autozone and they tell me I have a P0420 code which is the 3 way catalyst system and they say they can not erase the code for some reason.

I plan on getting a turbo kit for my KA when I have money so I figure I might as well just get a 3" high flow cat or resonated test pipe instead of buying a stock replacement.

Which high flow cat can I use to make the code go away? Do I need a special 3 way cat? Is there a 02 sensor inside the cat or something? I dont really understand how a cat can just go bad and throw a code like this.

This is the cat right below the exhaust mani correct?

Also I installed a cusco 2 way LSD, spl subframe spacers and ST rear sway bar and now I get a slight whining noise (mostly during acceleration). It gets kinda loud when im on the freeway going about 80.
Is this normal or do I need to move the flanges on the diff around? It doesnt clunk when going around corners but it does feel pretty rough only when I turn right and go over bumps while turning... Is that normal?

1 more thing... the endlinks I installed with the suspension techniques rear sway bar can not be tightened very tight without the poly bushings getting smashed and distorted which is how im driving on them now. Is it ok that they are smashed or should I back off a lil bit? I didnt want the endlinks to be too loose or theyd just fall off. Id get the spl rear endlinks but they want 200 bucks!

Any help is greatly appreciated.

[az_240]

damn only 5 views the entire day:wtf:

somebodys gotta know something about either of these

[shayrgob240]

is your car modified (engine mods)?

[charlie a.k.a. chuck]

Well your car needs 2 cats first of all and its triping a code because the cat on the mid pipe is missing. You could get a cat welded in between the 2 O2 sensors and erase the code and it should go away, thats if you dont have stock headers. If you do then i dont know check the cat if cloged if not you might need to replace the secound O2 sensor. I could be wrong.

[projectRDM]

Well your car needs 2 cats first of all and its triping a code because the cat on the mid pipe is missing. You could get a cat welded in between the 2 O2 sensors and erase the code and it should go away, thats if you dont have stock headers. If you do then i dont know check the cat if cloged if not you might need to replace the secound O2 sensor. I could be wrong.

Wrong. There is only one catalytic converter on the S14, right off the manifold. There is no stock 'header' either, it's called a manifold and downpipe, and that's where the OE cat resides, in between the OE O2 sensors. Replacing the secondary O2 sensor wouldn't do a thing if it's not throwing a code itself.
Now, if the cat is throwing it's own code and there are no other codes showing, replace it, either with another OE unit or a 3way unit downstream after the downpipe, in place of the OE resonator. If there's other codes too it's probably causing the cat failure, like a MAF or O2 code, or an overly rich/lean condition.

For the ST endlinks, they're supposed to see final tightening on the ground, loaded, and only until the bushings begin to compress. Sounds like yours are just overtightened, unless they're installed incorrectly. It should be:

nut
washer
bushing
Aarm
bushing
washer
spacer
washer
bushing
bar
bushing
washer
bolt

Check that and loosen as required.

[az_240]

No engine is not modified

There are no other codes... just the cat one. Can I replace it with a larger aftermarket cat and be good? Does it have to be the 3 way cat? im assuming they make larger performance 3 way cats if it does....? I basically dont want the restriction and dont want the code.

The endlink is put together correctly I just tightened it with the car off the ground:doh:

Im gonna try and move the flanges around and see if that helps with the whining on the diff.

thanks for the replys

[ManoNegra]

3" cat should be fine. OEM would be too costly new, used ones could be bad or going bad soon and hard to come by ie. not sold at junkyards.

[az_240]

I was searching around and found someone saying the OBDII will throw a code if I dont use the 3 way cat. So theres some mixed info... I thought cats were normally 2 way like catco cats. What hi flow cats do people use on their 96-98 240s to not throw a code and pass emissions? I read random tech cats are the only cats that can do this on OBD II cars but they are like 200 bucks!
Can anyone confirm this????

[projectRDM]

Any 3way cat. The trick is to mount the secondary O2 sensor behind it, so that's it's measuring an A/F change versus the primary sensor. RT sells one already fitted with the correct bung for both Zenki and Kouki models, or you can drill a weld a nut on yourself.

[az_240]

thanks R24
I moved the flanges around on the diff and it seems to not whine so bad...
SO MOVING THE FLANGES ON THE DIFF DOES MAKE A DIFFERENCE!
I searched and people were saying it wouldnt make a difference.
but it still does make a slight noise around 40+ mph... it still gets louder around 80mph too just not as loud as before.
I put shims where the diff bushings are too to tighten them up... I guess im just getting extra noise from the shims and subframe spacers.

Also fixed the sway bar endlinks... hopefully ma nuts dont fall off


One more question... do people usually just get rid of that first cat and replace it with a downpipe when they go KA-T? Or does the downpipe usually bolt onto that first cat? If it does usually get removed I might as well just buy a cheapie to pass emissions... if it usually stays ill get the RT I guess.

[projectRDM]

You can bolt an SR downpipe to the S14 manifold and just use a cat with floating flange.