Carburetor Calibration E2SE Series
NOTE: The E2SE carburetor has been calibrated at the factory and should not normally need adjustment in the field. For this reason, the mixture adjustment should never be changed from the original factory setting. However, if during diagnosis, the "System Performance Check" indicates the carburetor to be the cause of a Driver Performance Complaint, or emissions failure the carburetor can be adjusted using the following procedure. After adjustment, cover plugged areas with RTV rubber or equivalent.
Idle Mixture Needle Plug Removal:
Lean Mixture And Idle Mixture Adjustments:
CARBURETOR PRE-SET PROCEDURE:
1. Remove carburetor from engine following normal service procedures to gain access to plug covering the idle mixture needle. Remove plug.
2. Turn mixture screw in until lightly seated and back out 4 turns.
3. If the plug in air horn covering idle air bleed has been removed, replace air horn. If plug is still in place, do not remove plug.
4. Remove vent stack screen assembly to gain access to lean mixture screw. (Be sure to reinstall vent stack screen assembly after adjustment).
5. Turn lean mixture screw in until lightly bottomed and back out 2-1/2 turns. Some resistance should be felt. If no resistance, remove screw and check for spring.
6. Reinstall carburetor on engine:
a. Do not install air cleaner and gasket.
b. Disconnect the bowl vent line at carburetor.
c. Disconnect the EGR valve hose and canister purge hose at the carburetor and cap the carburetor ports.
d. Refer to Vehicle Emission Control Information label to disconnect temperature sensor on air cleaner and secondary vacuum break TVS switch, plug open hoses
e. Connect a dwell meter positive lead to the mixture control solenoid dwell test lead (green connector). Connect other lead on meter to ground. Set dwell meter to 6-cylinder position. Connect a tachometer to distributor lead (brown connector). (Tachometer should be connected to the distributor side of the tach filter if vehicle is equipped with a tachometer).
f. BLOCK DRIVE WHEELS.
g. Place transmission PARK (automatic transmission) or NEUTRAL (manual transmission) and set the parking brake.
7. Proceed to Mixture Adjustment Procedure.
Lean Mixture And Idle Mixture Adjustments:
MIXTURE ADJUSTMENT PROCEDURE:
1. Pre-set carburetor following procedure above.
2. Run engine on high step of fast idle cam until engine cooling fan starts to cycle. (At least three minutes and until in closed loop).
3. Run engine at 3,000 RPM and adjust the lean mixture screw slowly in small increments--allowing time for dwell to stabilize after turning the screw--to obtain an average dwell of 35 degrees.
- If dwell is too low, back screw out; if too high, screw it in.
- If unable to adjust to specifications, inspect main metering circuit for leaks, restrictions, etc.
NOTE: The dwell reading of the M/C solenoid is used to determine calibration and is sensitive to changes in fuel mixture caused by heat, air leaks, etc. While idling, it is normal for the dwell to increase and decrease fairly constantly over a relatively narrow range, such as 5 degrees. However, it may occasionally vary by as much as 10-15 degrees momentarily due to temporary mixture changes. The dwell reading specified is the average of the most consistent variation. The engine must be allowed a few moments to stabilize at idle or 3,000 RPM as applicable before taking a dwell reading.
4. Return to idle.
5. Adjust idle mixture screw to obtain an average dwell of 25 degrees with cooling fan in off cycle. If reading is too low, back screw out. If too high, turn it in. Allow time for reading to stabilize after each adjustment. Adjustment is very sensitive. Make final check with adjusting tool removed. If unable to adjust to specifications, inspect idle system for leaks, restrictions, etc.
6. Disconnect mixture control solenoid when cooling fan is in off cycle and and check for an RPM change of at least 50 RPM. If RPM does not change enough, inspect idle air bleed circuit for restrictions, leaks, etc.
7. Run engine at 3,000 RPM for a few moments and note dwell reading. Dwell should be varying with an average reading of 35 degrees.
- If not at 35 degrees average dwell: Reset lean mixture screw per Step 3. Then reset idle mixture screw to obtain 25 degrees dwell per Step 5.
- If at 35 degrees average dwell: Reconnect systems disconnected earlier (purge and vent hoses, EGR valve, etc.), reinstall vent screen and set idle speed(s) per Vehicle Emission Control Information Label on the vehicle. It is not necessary to repeat "Systems Performance Check" after proper adjustment of carburetor.