i was wondering what colorado does for their emission tests. visual and sniff? sniff at idle and 3000 rpm? test for CO, hydrocarbons, or oxides of nitrogen, or all three? any help is appreciated. thanks.

chevyismine

 

Visual inspection based on computer-generated check list. The list will include cat, evap canister, and gas filler restriction for any of our cars.

The car is run on a dyno while exhaust gases are collected and analyzed ("sniff" hardly applies here). When they start the car, they look to see if the SES light comes on when the ignition is turned on, and goes out after the engine starts. They look for smoke at start-up and during operation. The dyno run includes idle, stop-&-go, and highway cruise simulations.

There are various things that will be cause for stopping the test: holes in exhaust, overheating, unsafe operating condition, etc.

After the dyno test, they put the gas cap on a tester to verify it holds pressure adequately.

 

I was going to ask this question too.

I took my junk prelude in to be tested, and they popped the hood, and checked things out. (assuming they checked stock emissions, EGR, and the like)

Then they hooked up a tube to the exhaust pipe, and let it idle for a while. Then they drove forward onto a Dyno, and ran the engine for a while through the gears, while their computer checked the emissions.

Then they pulled forward, and tested the gascap.

I now wonder if I can pickup a stealthram, and somehow fake an EGR on it, then tune the heck out of things to keep emissions legal.