CALIFORNIA 2 SPEED IDLE TAILPIPE SMOG CHECK PROCEDURE

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THE FOLLOWING IS AN ARTICLE ADAPTED FROM THE 2013 VERSION OF THE BUREAU OF AUTOMOTIVE REPAIR MANUAL. IT DESCRIBES THE 2 SPEED-IDLE TAILPIPE SMOG CHECK PROCEDURE WHICH HAS BEEN ASSIGNED THE ACRONYM “TSI” (TWO SPEED IDLE).

  THE INSPECTION TYPE REQUIRED IN “BASIC” AND “CHANGE OF OWNERSHIP SMOG CHECK PROGRAM AREAS” IS THE AFOREMENTIONED “TSI” INSPECTION. IT IS ALSO NECESSARY FOR ENHANCED SMOG CHECK PROGRAM AREAS FOR VEHICLES THAT ARE INCOMPATIBLE WITH THE “ASM”  (ACCELERATION SIMULATION MODE). THE AREA OF THE STATE WHERE THE VEHICLE IS REGISTERED DETERMINES WHICH TYPE OF TEST THE VEHICLE IN QUESTION VEHICLE RECEIVES. SEE A SMOG CHECK PROGRAM AREA MAP HERE.

  THE TSI TESTING PROCEDURE REQUIRES TWO DISTINCT TEST SEQUENCES. PERFORMED FIRST IS THE 2500 RPM PORTION OF THE INSPECTION. THEN AN IDLE TEST SEQUENCE IS COMPLETED.THIS TESTING GATHERS EMISSION GAS READINGS FOR ANALYSIS. BEFORE THIS PART OF THE SMOG CHECK, THE TECHNICIAN PERFORMS A VISUAL INSPECTION.

  THE PURPOSE OF THE VISUAL INSPECTION IS TO CONFIRM THAT ALL EMISSION REDUCTION EQUIPMENT IS PRESENT. ALL EMISSIONS RELATED COMPONENTS MUST BE CONNECTED CORRECTLY.

  INSPECTORS MUST ENSURE THAT THE APPLICABLE BEFORE-TEST-CONDITIONS  ARE MET BEFORE BEGINNING THE TSI INSPECTION. ONCE THE APPLICABLE BEFORE-TEST-CONDITIONS ARE MET, FOLLOW THE EIS (EMISSION INSPECTION SYSTEM, SEE BELOW) PROMPTS TO CONDUCT THE TSI INSPECTION.

 THE 2500 RPM TEST IS PERFORMED FIRST AND RUNS FOR 30 SECONDS. IT REQUIRES THE ENGINE TO BE ACCELERATED TO 2500 RPM AND HELD AT THAT SPEED. THE EIS, DEFINED IN THE NEXT PARAGRAPH, PROMPTS THE TECHNICIAN TO COMPLETE THE 2500 RPM TEST. UPON COMPLETION OF THE 2500 RPM TEST, THE EIS WILL TRANSITION TO THE IDLE PORTION OF THE TEST. THE TECHNICIAN WILL BE PROMPTED TO RETURN THE THROTTLE TO IDLE SPEED, WHICH IS ROUGHLY 750 RPM.

FOLLOWING THE PERFORMANCE OF THE EXHAUST EMISSION PORTION OF THE INSPECTION, THE TECHNICIAN IS PROMPTED TO PERFORM THE “FUNCTIONAL” PORTION OF THE INSPECTION WHICH MAY CONSIST OF AN IGNITION TIMING TEST WHICH TESTS THE TIMING OF THE FIRING OF THE SPARK PLUGS AT THE OPTIMUM MOMENT TO PRODUCE THE MOST POWER AND KEEP EMISSIONS IN CONTROL.

  A LOW PRESSURE TEST OF THE EVAPORATIVE EMISSION SYSTEM WHICH CONTAINS THE FUEL VAPORS PRESENT IN THE FUEL TANK AND OTHER COMPONENTS OF THE FUEL SYSTEM IS ANOTHER POSSIBLE ELEMENT IN THE TESTING SEQUENCE. THESE VAPORS CONSIST OF “RAW” HYDROCARBONS, “RAW” MEANING THAT NO BURNING HAS YET TAKEN PLACE. OF COURSE HYDROCARBONS CAN ALSO EXIST IN A  PARTIALLY BURNED STATE AS WELL. IN EITHER FORM, THEY ARE DEADLY TOXINS TO ALL LIVING THINGS THEY ENCOUNTER.

FINALLY, MANY VEHICLE EMISSION CONTROL SYSTEMS UTILIZE A DEVICE CALLED AN EGR VALVE. THIS VALVE METERS EXHAUST GASSES INTO THE INTAKE MANIFOLD, MIXING THESE INERT GASSES WITH FRESH AIR AND THE ATOMIZED GASOLINE DROPLETS DELIVERED BY THE FUEL INJECTORS UNDER HIGH PRESSURE. ONCE MIXED TOGETHER, THE TEMPERATURE OF THE MIXTURE IS REDUCED SUFFICIENTLY TO IMPEDE THE FORMATION OF OXIDES OF NITROGEN, ANOTHER TOXIC GAS AND A MAJOR COMPONENT OF THE BROWN HAZE EFFECT SEEN IN MANY SMOGGY AREAS. IT USUALLY CONSISTS OF A PLUNGER THAT OPENS A PASSAGEWAY PERMITTING PASSAGE OF THE EXHAUST GASSES INTO THE INTAKE AND IS OPERATED EITHER BY A VACUUM APPLIED TO IT’S DIAPHRAGM, OR ELECTRONICALLY CONTROLLED.

THE EMISSION INSPECTION SYSTEM OFTEN REFERRED TO AS “EIS” ALSO MAY PROMPT SPECIAL TEST SEQUENCES FOR VEHICLES WITH KNOWN TEST INCOMPATIBILITIES. SPECIAL TEST SEQUENCES ARE EXPECTED TO BE FOLLOWED EXACTLY. NOT FOLLOWING THE SEQUENCE COULD RESULT IN CATASTROPHIC VEHICLE DAMAGE.

 INSPECTORS SHOULD NOT ARTIFICIALLY LOAD THE ENGINE TO ACHIEVE A TESTABLE IDLE RPM. THIS INCLUDES PUTTING THE VEHICLE INTO GEAR OR TURNING ACCESSORIES ON.(TURNING ON ACCESSORIES IS A TECHNIQUE OFTEN USED TO LOWER THE IDLE SPEED OF AN ENGINE INTO “TESTABLE RANGE” AND IS PROHIBITED,IN PART BECAUSE THE VEHICLE’S COMPUTER MAY MAKE CHANGES IN THE OPERATIONAL STRATEGY BY CHANGING THE AIR FUEL MIXTURE, EFFECTING EMISSION READINGS)

FOR FURTHER READING ABOUT THE 2 SPEED-IDLE TAILPIPE SMOG CHECK PROCEDURE, CONSIDER THIS ARTICLE.

NOTE: IF THE VEHICLE FAILS THE 2 SPEED-IDLE TAILPIPE SMOG CHECK PROCEDURE, “TSI” EMISSIONS TEST, THE EIS WILL AUTOMATICALLY PROMPT FOR AN ADDITIONAL CONDITIONING PROCEDURE. IT WILL THEN PROMPT TRANSITION TO A “SECOND CHANCE” EMISSIONS TEST.