Engine Controls - Basic Ignition Setting
85volvo02Subject: Product Basic Ignition
Setting. CARS
Computerized Ignition System
B121F, B23F, B230F Group
34
Date: No.
January, 1985 105
THIS SERVICE BULLETIN IS APPLICABLE TO THE U.S. AND CANADIAN MARKETS
IGNITION OPERATION CLARIFICATION
The computerized ignition system operates in two different modes;
START MODE - During and after start, below, a specific engine speed, the ignition advance is controlled by the distributor.
RUN MODE - After start, once the engine reaches a specific engine speed (start mode to run mode), the micro-processor in the control unit is "activated". The ignition advance is now controlled by the data stored in the control unit.
To achieve the correct basic timing when checking/adjusting the ignition timing, it is important to ensure that the ignition system is operating in the RUN MODE.
CHECKING/ADJUSTING BASIC IGNITION TIMING
The following instruction is applicable to engines equipped with computerized ignition systems:
MODEL YEAR ENGINE ENGINE CODE
1981-1982 B21F-MPG 49
1982 B21F-LH 48
1983-1984 B23FLH 88
1985 B230F-LH 88
1. Check function and setting of throttle switch. Adjust if necessary (Refer to Service Manual TP 30432/1, Page 64-65)
2. Start engine and increase engine speed to 2,000 RPM for 5 seconds.
3. Let the engine idle and check idle quality. Idle speed should be 750+50 RPM (MY-1982) 750+20 RPM (MY1983-). Make sure the idle is stable as variations could affect the ignition timing.
4. Check/adjust ignition timing. Specification: 12 deg. +/- 2 deg. BTDC. Adjust timing by turning the distributor.