Emissions - Catalytic Converter Odor Reduction Procedure
REFERENCE Emission Control NUMBER 001 DATE 08-29-86 MODEL AE7#, AE8#. AL3#
To reduce possible Catalytic Converter odors on vehicles equipped with the 3A-C, 4A-C and 4A-LC engines on 1983 and later California specifications, the idle CO must be set to 0.3% and the specified engine speed must be adjusted as shown below.
Power 4A-C 4A-LC
T/M Steering 3A-C '83 '84 '85 '86 '84 '85 '86
M/T W/O 5 M/T 650 rpm 650 rpm 700 rpm 700 rpm 650 rpm 650 rpm
4 M/T 550 rpm
With 800 rpm 800 rpm 800 rpm 750 rpm 650 rpm 650 rpm
A/T W/O 800 rpm 800 rpm 800 rpm 800 rpm 800 rpm 750 rpm
With 900 rpm 900 rpm 900 rpm 850 rpm 800 rpm 750 rpm
Procedures are as follows:
CARBURETOR:
1. REMOVE CARBURETOR
(a) Before disconnecting the vacuum hoses, use tags to identify how the vacuum hoses should be reconnected.
(b) Remove the carburetor from the engine.
(c) After removing the carburetor, cover the intake manifold with a clean cloth.
MAS PLUG:
2. REMOVE MIXTURE ADJUSTING SCREW PLUG (MAS PLUG)
(a) Plug each carburetor vacuum port to prevent entry of steel particles when drilling.
(b) Mark the center of the plug with a punch.
PLUG AND IDLE MIXTURE SCREW:
(c) Drill a 0.256 in. (6.5 mm) hole in the center of the plug.
NOTE:
There is only (0.04 in.) 1 mm clearance between the plug and idle mixture screw, drill the plug carefully and slowly to avoid drilling into the idle mixture screw. The drill may force the plug out at this time.
MAS Plug:
(d) Through the hole in the MAS plug, turn the mixture adjusting screw all the way in, using a small tip screwdriver.
NOTE:
Be careful not to damage the screw slot by tightening the screw too tight.
MAS Plug Removal:
(e) Use a 0.295 in. (7.5 mm) drill to force the plug off.
(f) Unscrew the mixture adjusting screw 3 complete turns.
Vacuum Hoses:
3. REINSTALL CARBURETOR
(a) Reinstall the carburetor on the engine.
(b) Reconnect the vacuum hoses to the proper locations. Refer to the Vacuum Hose Information label under the hood.
4. REINSTALL AIR CLEANER
5. WARM ENGINE TO OPERATING TEMPERATURE
Idle CO Concentration Adjustment:
6. ADJUST IDLE CO CONCENTRATION
(a) Remove the exhaust pressure hose from the bottom of the EGR modulator. Connect the hose to the exhaust analyzer sampling hose to measure CO levels.
Idle CO Concentration Adjustment:
Adjust idle speed and idle mixture
(1) Initial conditions:
^ Air cleaner installed
^ Normal operating coolant temperature
^ Choke fully open
^ All accessories switched off
^ All vacuum lines connected
^ Ignition timing set to specification
^ Transmission in N range
^ Correct fuel level should be even with the correct level in the carburetor sight glass.
^ Front wheels straight for vehicles equipped with PS
(2) Start the engine.
(b) Set idle CO to 0.3% by turning the idle mixture adjusting screw and the idle speed adjusting screw to the specified idle speed as shown below:
Power 4A-C 4A-LC
T/M Steering 3A-C '83 '84 '85 '86 '84 '85 '86
M/T W/O 5 M/T 650 rpm 650 rpm 700 rpm 700 rpm 650 rpm 650 rpm
4 M/T 550 rpm
With 800 rpm 800 rpm 800 rpm 750 rpm 650 rpm 650 rpm
W/O 800 rpm 800 rpm 800 rpm 800 rpm 800 rpm 750 rpm
A/T
With 900 rpm 900 rpm 900 rpm 850 rpm 800 rpm 750 rpm
NOTE: While adjusting idle CO, be sure that electric cooling fan is off.
PLUG IDLE MIXTURE ADJUSTING SCREW:
7. PLUG IDLE MIXTURE ADJUSTING SCREW
(a) Remove the air cleaner and EGR vacuum modulator bracket.
(b) With tapered end inward, tap the new plug (P/N 21785-13210) until it is even with carburetor surface.
(c) Reinstall the EGR vacuum modulator bracket.
NOTE:
Make sure all hoses are securely installed.
8. CHECK AND ADJUST FAST IDLE SPEED.
9. CHECK AND ADJUST TP SETTING SPEED.
10. CHECK AND ADJUST A/C IDLE UP IF APPLICABLE.
11. REINSTALL AIR CLEANER Reinstall the air cleaner and connect the air suction hose to air cleaner.
PART NUMBER INFORMATION
Part Number Part Name
21785-13210 Plug, Idle Limit