Part 5 - VJ9 California Emissions Requirements

WORK IN PROGRESS: More Photos and information coming 

1978 was the first year of National Highway Traffic Safety Administration's (NHTSA) Corporate Average Fuel Economy (CAFE) Requirements and the third year of the U.S. Environmental Protection Agency (EPA) Clean Air Act of 1970 regulations full implementation.

According to the fueleconomy.gov website, my California 1978 Trans Am with a 3-speed automatic transmission was rated for 14 mpg city, 19 mpg highway, and 16 mpg combined fuel economy. The annual fuel cost was estimated to be $656.00.  This is the exact fuel economy rating as a vehicle without the California emissions option.

My 1978 Pontiac Trans Am with an Oldsmobile 403 cubic inch (6.6L) engine came with option code VJ9 California Emissions Requirements. This option was required for vehicles built for sale in the state of California in 1978. This requirement is a result of the EPA and the California Air Resources Board (CARB) regulations. The option cost $75.00 extra bringing the total cost of my car to $8838.00.

The under hood vehicle emissions label and emission hose routing diagram

According to the 1978 Pontiac Service Manual, the VJ9 California Emissions Requirements required the following items:

1978 Oldsmobile 403 Small Block Engine

• L80 Oldsmobile 403 engine (VIN K) code VN-HY. This engine only has 185 horsepower, but it has an impressive 320 lb*ft of torque. This engine is part of the engine family 830M4UA 8BFV VN-HY. An automatic transmission was the only transmission available for this emissions option.

17058553 QuadraJet 4 Barrel Carburetor with no vacuum lines connected

Small port "B" Manifold Vacuum. Large upper port "T" Carburetor Bowl Vent, and large lower port manifold vacuum for the PCV valve.

Ports "K" and "H" Ported Vacuum

3 Ports at the rear of the carburetor: The upper port is the choke heater air inlet, the bottom two ports are manifold vacuum for the power brake booster (left) and the secondary vacuum break Thermal Vacuum Switch (right).

• California Emissions Quadra-Jet Carburetor. This carburetor, part number 17058553, is tuned for an automatic transmission only as well as low altitude California emissions. Most of the carburetor ports are labeled and called out on the vehicle emissions label referring to the emission hose routing diagram.

Air Injection Reaction (A.I.R.) Pump

7817872 Diverter Valve for A.I.R. Pump. Vacuum port is connected to manifold vacuum at carburetor port "B"

Left A.I.R. Manifold and 22034702 Check Valve

Right A.I.R. Manifold and 22034702 Check Valve

AIR - Air Injection Reaction. This system consists of an air pump, diverter valve, hoses, check valves, and tubes. The system pumps air into the exhaust ports on a warm engine under acceleration to help complete the combustion process after the exhaust gasses leave the cylinder help reduce Carbon Monoxide (CO) and Hydrocarbon (HC) pollution.

17075690 Back Pressure EGR Valve

• BP-EGR - Back Pressure - Exhaust Gas Recirculation valve. This valve is used to recirculate exhaust gas back into the Cylinders under Certain conditions (Typically acceleration) to cool the peak combustion temperatures. This will help reduce Oxides of Nitrogen (NOx) emissions. This valve will not function until coolant temperature is warm and there is a slight amount of exhaust back-pressure. The Letter "P" on the valve after the part number indicates the valve is a positive pressure operated valve. There was also a letter "N" on some other engine's EGR valves that indicated a negative pressure was required for proper operation.

7817872 Diverter Valve for A.I.R. Pump. Vacuum port is connected to manifold vacuum at carburetor port "B"

• Diverter Valve - This manifold vacuum operated valve at the rear of the AIR pump is responsible for preventing the AIR pump from supplying air into the exhaust system while decelerating. The valve opens when engine vacuum levels from carburetor port "B" are low (like during acceleration). When the diverter valve is closed, the air pump air exits the diverter valve through a silencer attached to the valve. (See the small holes on the right)

3-Port ACDelco Thermal Vacuum Switch Location at right front of the intake manifold

3-Port ACDelco Thermal Vacuum Switch Part Number 212-582

3-Port TVS Vacuum Switch Port Designations (accurate)

• DS-TVS - Distributor Spark Thermal Vacuum Switch (3-ports) - This prevents vacuum advance when the engine coolant temperature is below 120 degrees F. This helps warm up the engine more quickly. This valve permits full vacuum advance when the engine coolant temperature is above 220 degrees F. This valve is marked 210 (degrees F) on the base. 
• The top port (labeled 1) is connected to ported vacuum through the Distributor Spark Vacuum Delay Valve and the Exhaust Gas Recirculation/Distributor Spark Thermal Vacuum Switch which connects to a carburetor port "H".
• The middle port (labeled D) is connected to the distributor vacuum advance.
• The bottom port (labeled 2) is connected to a 4-way vacuum tee.
• The tee also connects to manifold vacuum at port "B" of the carburetor base.
• The tee also connects to the transmission vacuum modulator to control shift quality.
• The tee also connects to the A.I.R. Pump Diverter valve to exhaust pump output during deceleration.

DS Delay Valve Installed between bottom of 2-port TVS and top of 3-port TVS

Distributor Spark Vacuum Delay Valve

• DS - VDV - Distributor Spark Vacuum Delay Valve. This valve delays quick changes in the level of ported vacuum supplied to the distributor vacuum advance during rapid throttle opening (like heavy acceleration). When testing this valve, it should take 20 - 30 seconds for vacuum applied to this valve to drop from 15" to 0" Hg.

17056978 Evaporative Emissions Storage Canister

ACDelco A478C Evaporative Emissions Storage Canister Filter

• EEC - Evaporative Emission Control. This consists of a 4-port Vapor Storage Canister, Canister Filter, hoses, pipes, carburetor, fuel tank cap, and fuel tank. The Vapor canister stores gasoline vapors from the fuel tank and carburetor bowl when the engine is off and then pulls the vapors into the intake manifold and burns them as part of normal combustion during steady speed driving. The four ports in the above photo from top to bottom are: 
• Manifold Vacuum (5/32" small hose) connected to a vacuum port on the intake manifold in front of the carburetor.
• Carburetor Bowl (3/8" hose) connected at port "T" on the carburetor.
• Fuel Tank Vapor Line (5/16" hose) connected to the fuel tank.
• Purge line (1/4" hose) connected to ported vacuum at port "K" on the carburetor.
• EFE - Early Fuel Evaporation system. On the Oldsmobile 403 the EFE system consists of an exhaust crossover pipe that connects the left exhaust manifold to the right exhaust manifold. This crossover pipe has a 1" orifice in it which forces exhaust to also travel through the intake manifold crossover passage. This heats up the base of the carburetor and helps the liquid gasoline atomize and vaporize as it is pulled into the intake manifold, cylinder heads, intake valves, and cylinders. Gasoline vapors burn, liquid gasoline does not burn.

EGR Vacuum Delay Valve installed between bottom of 2-port TVS and the EGR Valve

EGR Vacuum Delay Valve

• EGR-VDV - Exhaust Gas Recirculation Vacuum Delay Valve. This valve delays quick changes in the level of vacuum supplied to the EGR valve for an extended duration under low engine vacuum conditions (like wide open throttle). This allows NOx reduction under heavy acceleration or rapid throttle movement.

2-Port ACDelco Thermal Vacuum Switch Location at left front of the intake manifold

2-Port ACDelco Thermal Vacuum Switch Part Number 212-29

2-Port TVS Vacuum Switch Port Designations

• EGR/DS-TVS - Exhaust Gas Recirculation/Distributor Spark Thermal Vacuum Switch (2-ports). This valve delays vacuum to the EGR and distributor vacuum advance valve during cold engine operation (Below 120 degrees F). This valve is marked 120 (degrees F) on the base.
• The top port (labeled E) is connected to a 3-way vacuum tee.
• The tee also connects to the EGR vacuum delay valve and the EGR valve.
• The tee also connects to the distributor spark vacuum delay valve and port 1 of the Distributor Spark Thermal Vacuum Switch.
• The bottom port (labeled S) is connected to a ported vacuum source (Port "H") at the carburetor.

The Original Bead Type Catalytic Converter. These were fairly restrictive and are no longer available

A brand new aftermarket monolithic California Emissions Catalytic Converter on my 1978 Trans Am

• OC - Oxidizing Catalyst. This catalytic converter uses extra oxygen from the air pump to reduce Carbon Monoxide (CO) levels by adding an additional oxygen atom to form Carbon Dioxide (CO2). The catalytic converter also reduces hydrocarbons (HC) (which is unburnt fuel) by completing the combustion of the HC with extra air from the air pump. These conversions heat up the catalytic converter to over 600 degrees F. 
• NOTICE: California requires all 1972 and above vehicles to have a catalytic converter that meets California emissions standards. Factory original equipment catalytic converters were the bead type and are no longer available. The only option available is an aftermarket "Direct Fit" (bolts in place of the original part) or a "weld on" catalytic converter. Each aftermarket catalytic converter must be marked with a certification code proving it is built for California. Do not purchase 49-State Catalytic Converters, they are not legal in California

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ACDelco PCV Valve CV679C fits into an ACDelco CV5004C Rubber Grommet

ACDelco 12C26 EGR Fresh Air Intake Filter and Tube Assembly

• PCV - Positive Crankcase Ventilation. This manifold vacuum supplied system keeps the engine crankcase pressures at a low vacuum level. Normally combustion blow-by would get past the piston rings and pressurize the crankcase, contaminate the engine oil, and promote oil leaks. The PCV system pulls the crankcase fumes into the intake manifold and burns them. The other half of the PCV system is the inlet breather filter and tube that connects the the air cleaner housing and the valve cover to pull in fresh air.

Carburetor Secondary Vacuum Break Thermal Vacuum Switch 560880

• SVB-TVS - Secondary Vacuum Break - Thermal Vacuum Switch. This switch controls the vacuum to the air cleaner TAC motor and the carburetor secondary vacuum break. The switch prevents the carburetor secondary ports from opening while the intake air temperature is below approximately 123 degrees F  This prevents a cold lean backfire from an inadequate air-fuel mixture. I have not been able to find this part in a GM part number or an aftermarket part. 
• The upper port on the far left (labeled E) of the photo is connected to manifold vacuum at the rear of the carburetor. It is also connected to the lower port on the left and feeds the Thermostatic Air Cleaner (TAC) door motor temperature sensor. 
• The port on the right (labeled S) connects to the carburetor secondary vacuum break and is open until the air temperature is above 123 degrees F.
• TAC - Thermostatic Air Cleaner - This system uses a thermal valve to control a vacuum motor and damper door in the air cleaner inlet port. The port will be closed to outside cold air until the air cleaner air temperature reaches 123 degrees F plus or minus 20 degrees. While closed, the air cleaner will pull heated air across the left hand exhaust manifold, through the stove pipe, the carburetor and intake manifold. The warm air will help atomize the fuel for better combustion and lower emissions.