3. California Emission Control
1963 Requires PCV on new vehicles, older
vehicles retrofitted from road draft tube
1966 exhaust emission standards for HC & CO
1966 emission testing began
1970 Evap. fuel systems, ‘71 for Fed
1971 NOX standards
1972 EGR systems, ‘73 for Fed
1975 Catalytic converters
From late 70’s to 1995, all computer control
vehicles were OBDI
1996 marked the start of OBDII
4. Types of Smog Inspections
Initial Registration into State
When you move to California
Change of Ownership
When a car is sold (Sellers responsibility)
Not necessary between Parent/Sibling
Biennial
Every Two years
New vehicle exempt first four years
5. Types of Smog Tests
TSI (two speed idle)
Used in Basic Areas (Butte County)
Used if 4x4 or AWD cannot be shut off
4 gas-Does not test for NOX
ASM (Acceleration-Simulation Mode)
Used in enhanced areas (Large Metro areas)
Uses Dynamometer to load engine
15/50 and 25/25 tests
5 gas-Test for NOX
6. 5 Gas Theory
The five main gasses that we deal with
when diagnosing gas engines are:
1. HC = Hydrocarbons
2. CO = Carbon-monoxide
3. CO² = Carbon-dioxide
4. Nox = Oxides of Nitrogen
5. O² = Oxygen
7. Hydrocarbons (HC)
HC is basically un-burnt fuel.
Producers of HC:
1. Fuel vapors from gas tank.
2. Unburnt fuel from ignition misfire.
3. Unburnt fuel from lean/rich misfire.
4. Normal HC level in exhaust of an catalyst
equipped vehicle is 50ppm or less
8. Carbon Monoxide (CO)
CO is a combustion process by-product.
Producers of CO are:
1. Excessively rich mixture.
2. Defective cooling system (too cold).
3. Poor compression will elevate CO.
4. Incorrect cam timing (retarded).
5. Restricted intake air filter (carbureted).
6. Normal CO in catalyst equipped vehicle
is .5% or less.
9. Carbon Dioxide (CO²)
Carbon dioxide is an indicator of the
efficiency of the combustion process.
The better the engine burns the fuel the
higher the CO² level should be.
1. Normal CO² level in a catalyst equipped
vehicle is 13-15%.
10. Oxides of Nitrogen (NOx)
NOx forms when combustion chamber
temperature goes above 2500°f
Producers of NOx:
1. Over advanced ignition timing.
2. Defective cooling system (too hot).
3. Combustion chamber deposits.
4. Inoperative EGR valve.
5. Excessively lean mixture.
6. Incorrect fuel octane rating.
7. Normal NOx levels vary with engine type.
11. Oxygen (O2)
O2 makes up approx. 20% of the air we
breathe. The amount of oxygen that
comes out the exhaust pipe depends on
how well the catalytic converter is
working and how well the engine is
tuned.
1. Normal O2 reading in catalyst equipped
vehicle is 1-3%.
2. Adding O2 and CO2 values together
should equal 15%.
13. Emission Control Devices
Positive Crankcase Ventilation
HC
Secondary Air Injection
HC
Charcoal Canister
HC
EGR valve
NOx
Catalytic Converter
Two way = HC, CO
Three way = HC, CO, Nox
14. First effort to reduce smog
Directs gasses in crankcase to be returned
to intake manifold and then burned in engine
Replaces crankcase fumes with fresh filtered
air from air cleaner
One of the biggest reasons that engines with
PCV systems began lasting longer
PCV=Positive Crankcase Ventilation
Valves
15. Way back when Road Draft
Tubes would spew everything…
17. A hose from the crankcase to
air filter and it’s all good!
18. First AI system added air to exhaust manifold to
complete combustion of HC’s
Systems now add downstream oxygen to
catalytic converter to promote combustion of
exhaust gases
Three types
Belt driven pump
Pulse air
Electric pump
Secondary Air Injection
