Pinpoint Test Em: Emission Compliance

• The engine or catalyst temperature are not warm and stabilized before the test.
• Excessive idling by the vehicle before the test.

Normal Operation and Fault Conditions 

If any new emission components are installed, carry out the following steps before repeating the inspection/maintenance test procedure:

• Reset the KAM. Refer to Resetting The KAM.
• To relearn some basic adaptive learning (trim) values, run the engine at 2, 500 RPM for 1 minute and idle the engine for 2 minutes.

Courtesy of FORD MOTOR COMPANY

Verifying an excessive grams per mile (gpm) indication using a parts per million (ppm) reading.

For excessive vehicle gas readings, compare the actual gpm reading to the gas cutpoint level needed to pass testing. This gives an indication of how much the ppm reading has to be reduced (if the actual reading is twice the cutpoint, the baseline reading has to be cut in half or more).

Example:

• The actual HC produced by a vehicle is 1.6 gpm. The cutpoint for HC in this example is 0.8 gpm. The actual reading is twice the cutpoint.
• The HC reading obtained for the same vehicle during the baseline drive averages 440 ppm. In order for this vehicle to pass the inspection/maintenance test, the HC reading from the verification trip must be at least half of the baseline reading, or an average of 220 ppm or less.
• This method only gives a general idea of how much the ppm reading needs to be reduced in order for the vehicle to pass an inspection/maintenance test that calculates gpm. This test is not exact. Experience still has to be used to determine if the emission readings are reduced enough for the vehicle to pass the inspection/maintenance test.

Possible Sources 

• Intake air system concern
• Exhaust system concern
• Fuel system concern
• Ignition system concern

For testing procedures refer to PINPOINT TESTS EM: EMISSION COMPLIANCE