Smog Check Question...

There's a visual inspection and then the sniffer test. Sniffer tests the NOx. Hydrocarbons (HCs), CO(Carbon Monoxide), and CO2. If you have any non carb approved equipment under the hood, you fail visual inspection, so you gotta be tricky. That includes aftermarket intake, headers, FPR... etc.

just keep it stock, pass the smog, then start installing all ur mods thats what i do,but that means you have to take everything off later for ur next smog test or u just find someone that'll pass it for some $ lol.

Shwaykid said:

There's a visual inspection and then the sniffer test. Sniffer tests the NOx. Hydrocarbons (HCs), CO(Carbon Monoxide), and CO2. If you have any non carb approved equipment under the hood, you fail visual inspection, so you gotta be tricky. That includes aftermarket intake, headers, FPR... etc.

Click to expand...

quoted for truth.

Right, I've done the smog check already. Most of the obvious mods I would remove before the test, but I probably wouldn't bother changing out fuel rails, injectors, plugs, etc.

My question is specifically for the sniffer part. Does it detect concentrations of emissions, like in parts per million as you would test for a chemical in pool water using a test strip? Or does it somehow act like a big pool filter and collect every little piece of dirt that passes?

It's just a sensor thing that's placed in the exhaust I don't see how it could do anything other than detect the concentration of emissions, but I want to be sure

the emissions test does read parts per million

So, if it reads parts per million.....

Then you could technically put a massive, clean-burning V8 engine in the back of your car and pass smog.

The engine must be same year or newer, have all factory emissions equipment installed, and then must be approved by a referee.

So, if that sniffer actually reads parts per million then I might have to consider an MX-8 conversion

Do we have any Smog-test technicians on here that can verify this?

Also, when your emissions are checked, does California have specific ranges for every vehicle? Or are all vehicles lumped into a category like compacts, sedans, trucks? Or does it go by engine size?