Your customer's car failed the state emission test. You do not have a dynomometer. Use your portable PDA scope and 5-Gas Analyzer. Results of the test , failed HC at 25 mph.
This is a well maintained high mileage car (200k) that has HC that is out of range. The first step is to perform a base line gas analysis on the road.
The first step is to perform a base line gas analysis on the road. Using the Gas Meter, select the min/max option to record the highest and lowest readings during the test and gas histograph provides a line graph during the entire test cycle. Perform basic tests, ignition, fuel system, data stream, codes. The basic functional tests indicated that the engine and fuel system was in good condition. Since the car has high mileage and a new Oxygen sensor, the catalytic converter should be tested. This test checks the cats efficiency in converting hydrocarbons to carbon dioxide by using the engine as a pump.
Precondition the converter and disable the secondary ignition. Crank the engine for ten seconds and read the highest level of HC and CO2. The HC levels should be less than 500 PPM and the CO2 levels should be higher than 12%.
The catalytic converter failed the test and was replaced. Again the Gas Meter and Gas Histograph were used to verify that the new part will correct the emission failure. Pictured below is the HC/CO2 test with the new converter.
Note: The HC is well below 500 PPM and the CO2 is above 12%. This cat is doing a good job of converting hydrocarbons to carbon dioxide. The next step is to duplicate base line tests during a road test. The Gas Meter and Histograph have verified that the emission system repair was successful. The vehicle inspection report below confirms the success of the repair.
