Ignition Timing: Adjustments

***UPDATED BY TSB #G00190, JUNE 8, 1990

NOTE: On this distributorless ignition (DLI) system, ignition coil discharge is bipolar -- one side is negative, the other positive. A timing light designed to meet discharge from the negative terminal only will not light or will only light intermittently at the positive terminal.

This condition is a result of timing light design, not vehicle malfunction. Follow these steps to avoid misdiagnosis:

1. Check that your timing light operates correctly when connected to either the positive or negative side of the DLI system. If it does not, do not use it on this system.
2. When purchasing a new timing light, determine whether or not it can be used on DLI systems.

PREPARATION

Adjustment Preparation:

CAUTION: Be extremely careful when making connections to the diagnosis connector. Incorrect connections will cause component damage.

1. Warm engine to operating temperature.
2. Turn all electrical loads "OFF."
3. Check engine condition (spark plugs, hoses, etc.)
4. If using Mazda System Selector (SST #49 B019 9A0), connect to diagnosis connector. Set test switch to "SELF-TEST" position.

NOTE: If SST is not used, install a jumper wire between diagnosis connector "TEN" and "GND" terminals.

5. Connect timing light to diagnosis connector terminal IG-.

NOTE: When using an externally powered tachometer and/or timing light, connect it to the power connector (Blue: 1-pin). Do not ground power connector or 20A wiper fuse will blow.

ADJUSTMENT

Timing Adjustment:

1. Check idle speed and adjust to 850 ± 50 rpm if necessary. Refer to IDLE SPEED.
2. Verify that timing mark (yellow) on crank pulley and timing belt cover are aligned:

10° ± 1° BTDC

3. If not, loosen crank angle sensor lock bolt and turn sensor to adjust.
4. Tighten crank angle sensor lock bolt to 19 - 25 Nm (14 - 19 ftlb).
5. After adjustment, disconnect SST or remove jumper wire from diagnosis connector.
6. Rev engine and verify that timing advances.