California used to run the car on rollers for the emissions, so idle not moving, then under load at 15MPH and at 25MPH... And I have personally seen a sniffer test on a well tuned car with no Catalytic converters pass emissions under those conditions.

Now on OBDII cars they just plug into the OBDII and look for all sensors reporting good and a visual inspection for aftermarket parts and the corresponding CARB EO numbers. This is where the problem likely is, the default BAMA tunes have rear O2 sensors turned off, they will therefore read NOT READY, automatically failing the OBD test. The owner needs to request an emissions tune, load that, and go through the drive cycle procedure linked to somewhere above.

 

I wasn't aware of the rollers part, although that still sounds like it only measures constant speed/steady state conditions.

Do they still use that approach for pre-OBDII vehicles?

NJ also uses the OBDII scan with an undercar mirror check for the existence of converter(s), but I'm not sure if they even look for anything else.


Norm

 

I left California in '07. I had been running a '78 BMW 320i with a cam, distributor, ignition, fuel injection modifications. And, I had been running a 49 State Cast Iron Exhaust Manifold for many years. The OEM California exhaust manifold was called a "Thermoreactor" made out of steel, designed to superheat the exhaust and did not have a catalytic converter. In fact there were rumors of people complaining that dry cleaner bags in the trunk were melting, and it was recommended not to park it in tall, dry grass or such, even with the factory's extensive heat shielding under the car.

In '07 my car was introduced to the "rollers" and after several tries, leaning out, adjusting timing, and so on, it was just barely getting by the tail pipe sniffer test. Then the tester said "you don't have the original exhaust on there, so you fail".

That "Thermoreactor" original had been in rafters since the car had 18k on it. Those things had "mile switches" in the odometer cable system for "warnings" at some intervals, one being about 25k. Over time they would fall apart due to heat and such. Over the years I watched what a new "exhaust manifold" would cost in California. The last I can recall was nearly $5,000! Bottom line I couldn't get the offending manifold off, it had been there so long that it had several fasteners that would not yield, my old body quit on me. Sold it for a song, don't know what the buyer did. FYI FWIW

 

I suspect they do still use the rollers with pre-OBDII/post 1975 cars.
Yeah it's steady state, but under load. Can you imagine trying to measure acceleration in a fair manner? Couldn't even get the same car to give the same results in the same shop by the same technician two times in a row.