July 15, 2024
Emissions Test – 10 Top Tips to Pass the Emissions Test

Many states and counties require your vehicle to pass an emissions test every couple of years. Your car, truck or van cannot be driven or sold without a clean bill of health. Here are ten top tips to make sure your vehicle will pass the inspection.

1. If the “check engine” light is on, you will not pass the emissions test.
If it just recently came on, maybe the problem is something short-term and will go away after several driving trips. But if not, you will have to take care of whatever is causing the problem (see below).

2. Get an oil change if you haven’t got one in the past couple of months.
Sometimes gasoline can contaminate your oil in the crankcase which increases carbon monoxide emissions.

3. Change the air filter while you’re at it.
A dirty air filter can also increase carbon monoxide emissions and you can fail the emissions test.

4. Put in new spark plugs, properly gapped.

5. Check your gas cap to make sure it has no cracks, and that it fits and closes tight.
If there’s any problem with it, get a new one. Make sure the gas cap is tightly closed with three clicks before you go for the test.

6. Fill the tank with premium gasoline.
You don’t want unburned gas anywhere but in the gas tank. Higher octane gas will burn better. You can go back to the “cheap stuff” after the inspection.

7. Add some “dry gas” or other gas additive to your tank.
When you drive the car to warm it up for the test, the additive should help clean the catalytic converter and exhaust system.

Note: Be sure to read the labels for the right additive and follow the instructions.

8. Make sure your tires are at their full air pressure.
The emissions test may include putting your car on the dynamometer. The tester will check it for emissions while driving your car on a spinning cylinder at various speeds. Properly-filled tires will help maintain a more even performance and lower the risk of failure.

9. Arrive at the inspection site with half a tank or less of gasoline.
This can also help prevent any gas getting in places you don’t want it during the emissions inspection. You may want to keep this point in mind when you “gas up” according to tip number six.

10. Drive the car for about half an hour before the test and idle the engine while waiting in line.
The idea is to have the engine warm and operating at its peak fuel-burning efficiency. This will also help mix your additive and get it into the fuel system.

If the “check engine” light stays on, or if following these tips doesn’t get you through the emissions inspection, there are still a couple of things you can do.

A handheld diagnostic scanner can easily turn off the check engine light. Even if the light is off, your vehicle’s computer may still hold diagnostic trouble codes. A decent scanner will also be able to reset these codes.

However, your vehicle may trigger those same codes on the way to the inspection site. Even if it does not trigger the check engine light, you will fail the emissions test when they hook up their scanner to your car’s computer. Your scanner can detect and read trouble codes whether the check engine light is on or not.

The scanner tool can tell you where to look for emissions and engine-performance problems. With it you can check your car engine’s oxygen sensors and many other parameters to find the system and sub-system where the problem lies. Fix the problem and you will be sure to clear the emissions test.