need help clearing code

[ozzie84]

i got till the end of the month to clear this code (code 0420) thats not letting me pass the state inspection
I have a cali-equipped miata (99) and with my research it seems to be the pre-cat which are exuberantly expensive...
i do have an 01 header with egr....how hard would it be to swap out and would that even work?
i also have a the cat resonator from the 01 too if that is needed.


any help would be appreciated.

[OZMDD]

A spark plug anti-fouler on the O2 sensor (assuming it works properly) should take care of any issues with a weak pre-cat. Getting enough drive cycles on the ecu to get the requisite "ready" states before Thursday might be tricky...or a treat!

[ozzie84]

would that be done on the first or second sensor?

[OZMDD]

Typically it is done on the sensor that is downstream from the cat, since we are presuming that the cat is not doing its job well enough to make the ecu happy. The anti-fouler pulls it out of the stream and hopefully allows it to get a satisfactory value.

[gabkwong]

Put the anti-fouler AFTER the 2nd CAT. It should work. Don't ask how I know.

[motorollow]

Gabkwong knows

[black roadster]

Put the anti-fouler AFTER the 2nd CAT. It should work. Don't ask how I know.

How do you know Gabe?

[gabkwong]

BR, if you come to house I can"show" you!

[ozzie84]

Was finally able to install it..i cleared the code with my obd2 reader and now to drive a lot tmrw

[sammm]

^It's now in a 'not ready' state and that will fail you too. You'll need several drive cycles to get it back to ready.

[black roadster]

Actually you can have one "Not Ready" and pass.

[ozzie84]

i think they guy told me the limit is two, and still pass

[BigDmiata]

From DPS website

Effective October 15, 2008:

For vehicles year model 2001 and newer, we allow one (1) non-continuous monitor to be Not Ready and still pass the test, but two (2) or more Not Ready's will cause the vehicle to fail.

For vehicles year model 1996 – 2000, we allow two (2) non-continuous monitors to be Not Ready and still pass the test, but three (3) or more Not Ready's will cause the vehicle to fail.

[ozzie84]

ok so the guy was right...
he told me to run the car roughly 40 miles after clearing the code, before trying to test again

[BigDmiata]

If you don't have an obd2 scanner, autozone can probably check to see if the monitors are ready.

[effse7en]

One of the monitors is dependent on the car's performance on deceleration, so just coast down from speed without the brakes a few times and you'll have the monitors set in no time. We can do it in about 15 minutes and less than 10 miles haha
Also the EVAP monitor pretty much can't be set with any effort on your part. Just leave it overnight, and it should set. That's usually the one we leave as "not ready" if we have to :P

Oh, and if you've already failed the test once this year, ALL the monitors have to be set to pass.

[ozzie84]

Motha truka passed!!!!

[ozzie84]

Thanks everybody for talks help and suggestions