Page 202 - CTS - Mechanic Diesel - TP

MECHANIC DIESEL - CITS

TASK 6: Examine the results
Compare the test results with std value of emission standards and identify the cause of a drive-ability problem as
shown in the table below .

IDLE 2500 RPM Probable cause

HC ppm 0-150 0-75 Normal reading
Co% 1-15 0.0.8
CO2 10-12 11-13
O2% 0.5-2.0 0.5-1.25
NOx ppm 100-300 200-1,000

HC ppm 0-150 0-75 Rich mixture
Co% 3.0+ 3.0+
CO2 8-10 9-11
O2% 0.-0.5 0-0.5
NOx ppm 0-200 100-500

HC ppm 0-150 0-75 Lean mixture
Co% 0-1.0 0-0.25
CO2 8-10 11
O2% 1.5-3.0 1.0-2.0
NOx ppm 300-1000 1000+

HC ppm 50-850 50-750 Lean misfire
Co% 0-0.3 0-0.3
CO2 5-9 6-10
O2% 4-9 2-7
NOx ppm 300-1000 1000+

HC ppm 50-850 50-750 Misfire
Co% 0.1-1.5 0-0.8
CO2 6-8 0-10
O2% 4-12 4-12
NOx ppm 0-200 100-500

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CITS : Automotive - Mechanic Diesel - Exercise 12.1 CITS : Automotive - Mechanic Diesel - Exercise 12.1