Performing proper and regular vehicle maintenance according to your owner manuals and not tampering with the emission control equipment are keys to passing smog check.
Warming Up:
Drive your car for about 20 minutes before arriving at your smog inspection center. This will give your car enough time for proper engine combustion to occur.
Tire Pressure:
Check your tires and tire pressure. Uneven, worn tires and incorrect tire pressure may cause incorrect emission test results.
Fuel Additives:
Emission levels can be lowered by using fuel additives to the gas tank, which improves your combustion process and engine performance.
Change Oil:
Regular oil changes can help you pass your smog check. Bad fumes from your oil pan leak into your engine and can fail your smog inspection.