State of California

San Franciscan Hotel
Crystal Ballroom
1231 Market Street
San Francisco, CA

April 23, 1980
10:00 a.m.



80-7-1 Public Hearing to Consider Changes to Evaporative 001
Emission Regulations for 1981 and Subsequent Model-
Year Motor Vehicles.

80-7-2 Public Hearing to Consider Amendments to Title 13, 023
California Administrative Code, Regarding Parameter
Adjustment of Idle Air/Fuel Mixtures on Heavy Duty

Other Business
a. Research Proposals
b. Delegations to Executive Officer
c. Executive Session

ITEM NO.: 80-7-1

Public hearing to Consider Changes to Evaporative Emission
Regulations for 1981 and Subsequent Model-Year Motor Vehicles.


The control of evaporative hydrocarbon emissions began with 1970
California passenger cars and has since been extended to all
motor vehicles. Beginning with the 1978 model-year, an emission
standard of six grams per test as determined by the SHED
procedure was implemented. The standard was subsequently lowered
to two grams per test beginning with the 1980 model-year. At the
two-gram standard, a background allowance (subtracted from test
data) of one gram for non-fuel chassis emissions has been
permitted to compensate for paints, plastics, lubricants and
rubber components of new test vehicles. EPA regulations do not
permit the allowance even though a two-gram standard is
implemented on 1981 and newer federal vehicles.

A review of the 1980 California certification fleet shows that
the background allowance was not needed for more than 96% of the
vehicles. Vehicle manufacturers apparently are able to reduce
and stabilize these non-fuel emissions through various cleaning
and aging techniques. Therefore, the staff recommends that the
Board eliminate the background allowance by adopting Resolution
80-8 and amending its evaporative emission test procedure for
1981 and newer vehicles. This change will then bring the
evaporative emission standard for light-duty and medium-duty
vehicles into conformance with the comparable federal standards.

ITEM NO.: 80-7-2

Public Hearing on the Proposed Changes to Regulations Regarding
Limited Parameter Adjustability of Idle Air/Fuel Mixtures for
Heavy-Duty Engines for 1982 and Subsequent Model Years.


Sections 39601, 43100 through 43104 and 43210 of the Health and
Safety Code authorize the Air Resources Board (ARB) to adopt
rules, regulations, and test procedures for the certification of
new engines and vehicles in California. The federal and
California certification procedures currently require
manufacturers to demonstrate that their heavy-duty gasoline-powered
engine exhaust emissions will be in compliance with the
exhaust emission standards for at least 50,000 miles.

Surveillance testing of in-use passenger cards, light-duty trucks
and medium-duty vehicles by both ARB and the Environmental
Protection Agency (EPA) have found that these vehicles' emission
control systems were not performing in customer service as they
performed during certification testing. This reduced performance
is to a large extent due to tampering and maladjustments of
emission-critical components. An important aspect of the
maintenance problem as determined from these surveillance
programs, was that a substantial amount of maladjustment to the
idle air/fuel mixture was either intentionally or inadvertently

A comparison of these data with heavy-duty vehicles can be made
since many engines used in medium-duty vehicles are similar to
engines used in heavy-duty trucks and since carburetors of all
gasoline-powered vehicles are very similar in design. These data
compare favorably with EPA's heavy-duty inspection/maintenance
data from Oregon and New Jersey which indicate that the heavy-duty population
is also afflicted by tampering and maladjustments.

These proposed regulation changes would allow only limited
parameter adjustability of the air/fuel mixture beginning with
the 1982 model year and would, in addition, improve these in-use
gasoline-powered heavy-duty vehicle emission performances. The
staff concludes that the technology required to build acceptable
vehicles with limited parameter adjustability exists for
gasoline-powered heavy-duty engines and vehicles. Since it has
been shown that routine maintenance will not solve the
maladjustment problem, it is recommended that a greater degree of
non-adjustability be required for the fuel metering systems of
gasoline-powered heavy-duty engines and vehicles.

The staff recommends that the Board adopt Resolution 80-10 which
adopts a new 1981 model year heavy-duty engine test procedure and
amends its exhaust test procedures for 1982 and subsequent model
year heavy-duty engines to limit the adjustment of the carburetor
idle air/fuel mixture.