Tips: How to use the emission test result ~ Cars and Bikes
Cars and Bikes

Friday, 25 July 2008

Tips: How to use the emission test result

Most of the people think that the emission test is for pollution control, it is true, however the engine condition can also predicted from the emission test result. Herewith some of information that we can get from the emission test result (base on EURO II spec) :

CO content (maximum 2.5%)
CO content is depend on mixing composition between air and fuel. If the result more than 2.5%, check the following:

  • Air filter, probably dirty
  • Throttle choke, clean it from carbon deposit
  • Adjust the air-fuel mixing in the carburetor or check the CO sensor for an fuel injection engine.
  • If your car still using carburetor, clean the intake.
  • Check and clean the injector

HC (Hydro Carbon) content, maximum 400 ppm
This one related to combustion process. If the result exceeds 400 ppm, try the following step:

  • Check the spark plugs, spark plug cables and ignition coil
  • Check and adjust the spark timing, advance timing could rise the HC content.
  • Measure the combustion chamber compression (with compression meter), if the result lower than it should be (read the vehicles manual), probably there is a leak in compression.

O2 (Oxygen) , 0.5 – 2 %

The O2 is burn during combustion process, so the test result should be as low as possible. If higher than 2%, it sign of leaking in exhaust system

  • Check the muffler condition
  • Check exhaust manifold gasket for leak
  • Check the exhaust pipe connection for leak

CO2 (Carbon dioxide), > 12%
A perfect combustion will produce high CO2 with little bit water. If the CO2 content lower than 12%, we can suspect some problems:

  • The composition of air and fuel mixture was not balance, too rich of fuel or lean of fuel.
  • Compare the CO2 result with HC and CO results.

Lambda 0.95 – 1.05
Lambda is a number showing the mixture of air and fuel. Lambda 1 is perfect number, that mean the mixture is 14.7 (air) : 1 (fuel). If the Lambda more than 1.05 , that mean fuel percentage less than it should be, the engine will knocking, less power and tend to be overheat. If the lambda number less than 0.95, the fuel consumption tends to be higher.

No comments: