Passing emission test.

[gmctrucks]

Posted: 2009-01-29, 00:14 Post subject: P0421 what do you think of this I found this on another site, what do you think?
This fix will basically get rid of a SES due to error code P0421 (Warm Up Catalyst Below Threshold (Bank 1)) caused by either a test pipe/down pipe (No Cat) or a High Flow Cat. When this light comes on from your install of a new exhaust/header/etc, be aware that this has no effect on the performance of your car. its just a stupid reminder that the o2 sensor is finding a problem involving something to do with the stock catalytic converter. Yes, by the way, an o2 Sim would do the trick too, but why spend upwards of $50 and have to deal with the cost/install/and problems associated with that kind of fix when you can just do this for about $5 bucks?

Pre-Install
- You might have space for only 1 spark plug anti-fouler, sometimes using 1 will work, sometimes not.
- Having an electric drill helps out tremendously, those battery operated ones dont have that much power; they will still work but will be a pain
- This may still not solve your problem of the light; a small amount of people that try this 'quick fix' still cant get the light to go off, this could be due to having multiple error codes. It SHOULD fix P0421.

STEP 1
-purchase 1 package of 2 spark plug anti foulers at your local auto parts store
- 18mm size
-made by HELP! (Part #42002)


STEP 2
-disconnect the negative terminal on your battery. this will reset your ecu
-take one of the anti foulers and drill out its center using a 1/2 bit, this will increase its hole size and allow your stock o2 sensor to fit. If you can only fit one under there, use this one.



STEP 3
-screw the drilled spark plug anti-fouler on top of the original
-be sure to use some kind of anti-seize on the treads. in case you need to remove your fix with ease



STEP 4
-jack the car up or use a lift
-unscrew your stock o2 sensor and place the foulers in
-use anti seize on the threads
-clean your o2 (by wiping it off with a paper towel DO NOT GET IT WET!)




STEP 5
-reinstall your o2 sensor
-use anti seize on the threads



STEP 6
-reconnect your battery (Resets your ECU)




DSCF0194.jpg - File downloaded or viewed 1035 time(s)



foulers0001.jpg - File downloaded or viewed 1037 time(s)

Say members our 2001 Mazda MPV wouldn't pass the emissions test so I did this trick and she passed with flying colors.
GMC
PS-I hope this helps other Mazda owners or others in general. Also my cordless De-Walt drill did the job just fine I guess it could also be due to having a good drill bit plus a good drill. This trick saved me a lot of money.

[bubbatrucklover]

I only scanned this post but will re read and get back with opinions comments questions. Sounds cool though.

Right now I can't figure out how to take my 02s out(ALL Fn 4 of them) read the book "thought" it was easy but, don't want to be bull headed and break something.

and as far as your choice of drill..................... all my power tools are Black and Yellow(bought some Stanley hand tools to match)

[mudseeker]

all you're doing is moving the sensor out of the exhaust stream. it is not solving the problem, just masking it and your engine is still not operating corectly. if you're on a budget and it works then go for it, but don't forget to fix the problem later.

[gmctrucks]

I'm going to get a free flowing Cat put on it at a later date bad timing right now I have Christmas gifts to take care of now especially for my grandkids.

[BernieB]

Any inspection station doing a visual check will probably spot that. Probably an automatic fail and/or citation for emissions tampering.

[gmctrucks]

Bernie I know it's wrong and I do feel bad but hard times right now and I am going to put on a new Cat as soon as I can because I don't feel good about it and it's not doing it's job right now plus I wouldn't want to mess up the engine. I have been looking for a new Cat I know one is going to come along soon at a good price. If you guys happen to find a free flowing Cat please let me know. On out older MPV that my sister has right now I had a Magnflow Cat put on it due to it the OEM was bad I found it on www.craigslist.com

[BernieB]

Not judging you GMC; it isn't my place to do that. I think of you, and the other active members of the forum as friends, and I don't think I'd be a very good friend if I didn't give you my honest thoughts on something like this. I figured you knew that this setup isn't legit but just in case you didn't...

Besides, you know as well as I do that somewhere, at this very moment, there's probably a newbie looking at that post and thinking, "Cool! And it's perfectly legal and legit, because everything you see on the Internet is real and legal, right?"