Hi all,

I am wondering if someone can help be figure out how to get my FD to pass CA smog?!?!

My HC and CO are through the roof.

I have put everything back to stock except the intake which has a CARB sticker. I put in a new cat and new custom downpipe with 2 pre-cats, changed the plugs and o2 sensor but it still won't pass! The engine does have a mild street port and I am worried that without some sort of aftermarket ECU I won't be able to get it to pass...

Is it possible to run an aftermarket ECU and still pass CA emissions?!?! Do they check the ECU codes on a 93?

Anyone know a good tuner in the SF bay area who could get this thing to pass smog?

Thanks for your help!!!!

 

Is the cat converter a stock Mazda part, or is it an aftermarket type? The high-flow units are generally not adequate for some reason; the Mazda cat spreads air from the air pump throughout the interior of the cat, whereas some aftermarket parts just inject air straight into the cat shell, and are not as complex as the OEM cat.

Other possibilities are mis-connected vacuum line(s), a bad electrical connection to the ACV (maybe a pinched/shorted wire), etc. Our '94 was a gross polluter from the day we bought it (new). Somehow a couple of solenoid rack hoses were swapped, plus there was a pinched wire. We have had good emission testing results since that fix, except when I replaced the stock cat with a Bonez unit, failed smog, and had to fork out for a new OEM cat, which fixed the problem.

Our '94 is nearly stock (see signature below). I posted our smog test results for 2010, 2012, and 2014 previously on another forum... here they are again. Keep in mind there is no pre-cat (replaced by a downpipe), no EGR, and a lower-temperature coolant sensor. Note mileages... on original engine.

 

I'm assuming you have a working air pump?

 

If you have a good OEM cat, the OEM ECU and a correctly functioning air injection system you should be able to pass. I did this recently on my 95 that had been gutted for smog. After reinstalling everything and confirming that the air pump was switching correctly, off it went and passed easily.

If you don't have a good OEM Mazda cat, and the air system working correctly you probably will never pass. You need the OEM ECU since the tech looks for the check engine lamp to illuminate and go off. There is a way to rewire the lamp to work with a PFC but I think that will just introduce another problem.

If you are using a stock cat in good condition then I would check out your air pump/switching system for correct function. You might also want to make sure your fuel pressure is correct, I imagine if it is high then the car would run richer than normal and cause a fail, also.

 

living the dream, my friend