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Just curious, but what kind of ecu/vaf combo are you running??? If it's a chipped ecu, and the fuel map was set too rich, would that not be a possible reason????

Yes what ECU are you using? I'm using AMSOIL and my emission test went way better this year. I recommend you Seafoam the engine anyway as a bottle is only 12 bucks at WalMart. I did my engine just days before the test. High flow cats are notorious for failing emissions test IAW a friend at a test center. Like I said before, ask the test guy to keep the RPM as close to 2300 not 2500 as I found the HC much lower at the lower RPM.
For your CO that's the job of the EGR isn't it but we don't use one. It's my opinion a new stock cat would help you. I used about 5oz of acetone as well and it's common knowledge you should use the 10% ethanol/methanol blended fuel not gas line antifreeze.
My Test
2500 (2300) rpm. HC 169, CO 1.34
IDLE rpm. HC 179, CO .42

I have a 2.5" exhaust and I feel that contributes to a rich running engine.

Seafoamed the car before I sold it and those plugs were done in fall of last year, they should be good and I gapped them correctly.

Check the OHM resistance in the wires.. Also, I agree with Dan. Run a new oem style cat to replicate a normal stock setup.

any chance the new o2s faulty heater could be throwing the CO emission off so far from the previous test? 1st 2 tests were with original o2s and last 2 were with the new ones.

car has a probinator chipped mx3 ecu, curved neck intake and the stock mx3 vaf as far as i know.

I'm still thinking it's the probinator chip...wouldn't be the first time it caused a ze to run too rich. Here's an example...down towards the bottom:http://www.mx6.com/forums/canada-buy-se ... eeded.html
If you had a non chipped ecu, I think it'd be worth a shot...

The O2 heater is only used to initially heat the sensor, once the engine is hot it's no longer needed so if it was bad it wouldn't matter anyway.

go back to stock as much as possible.

EGR, newest and best cat you can afford, 2.5 un-chipped ECM, and then it should be good, Mazda wouldn't build them to fail from factory.

I have run a kl01 on that car and it ran good. I would try to find a kl47 ecu and run that

Ryan wrote:go back to stock as much as possible.

EGR, newest and best cat you can afford, 2.5 un-chipped ECM, and then it should be good, Mazda wouldn't build them to fail from factory.

dont i need to swap heads with a de to attach an egr? as far as i remember the egr bolted onto the rear cylinder head? im gonna give this shop a try with it and see what happens.

The way I passed emissions last time was doing this:

Driving the car hard right before going to the station (hard acceleration, high speed)
After that pull over and doing the following:
2 20 oz bottles of acetone (90% isopropyl) on a mostly empty gas tank
Remove air filter
Unplug PCV valve

Last test results:
Idle emissions: HC 164, CO 0.4187
CO+CO2 14

I've actually got to go pass the test again tomorrow. I'll let you know how it goes... hopefully I pass!

SeaFoam that puppy Moon (I cheated last time by pulling the PVC but this time I passed easily without removing it). Acetone is the demon sheet for sure. Actually acetone does a lot of good stuff, research it.

for all you guys that have to pass emissions, why dont you just make a double/triple cat setup that can bolt in like a test pipe? Wouldnt that be a whole lot easier than all this chemistry and plug wire deals, install multiple cats pass test then remove and reinstall is what i would do.

^ This

Sleeper6 wrote:for all you guys that have to pass emissions, why dont you just make a double/triple cat setup that can bolt in like a test pipe? Wouldnt that be a whole lot easier than all this chemistry and plug wire deals, install multiple cats pass test then remove and reinstall is what i would do.

been there. done that. still failed .

Make about 10L of homebrew and run her on that