See Figures 1 through 5
SINGLE POINT AND ELECTRONIC DISTRIBUTORS
- Warm-up the engine, then shut the ignition OFF .
Before hooking up a tachometer to a 1975-77 car with a transistorized ignition system, refer to the preceding service precautions located under the point and transistorized point type ignition system information earlier in this section. On all models equipped with a transistorized point or fully electronic ignition, hook the dwell meter or tachometer to the negative (-) side of the coil, not to the distributor primary lead; damage to the transistorized switch or ignition control unit will result
- Connect a tachometer (following the tool manufacturer's instructions) and check the engine idle speed to be sure that it is set to specification.
1983 and later A-series engines require a special type of tachometer which hooks up to the service connector wire coming out of the distributor. As many tachometers are not compatible with this hook-up, we recommend that you consult with the manufacturer before purchasing a certain type
- If the timing marks are difficult to see, use a dab of paint or chalk to make them more visible.
- Connect a timing light according to the tool manufacturer's instructions.
- Disconnect the vacuum line(s) from the distributor vacuum unit. Plug each disconnected line using a pencil or golf tee.
- Be sure that the timing light wires are clear of the fan, then start the engine.
- Allow the engine to run at the specified idle speed with the gearshift in Neutral (manual transmission) or Drive "D'' (automatic transmission).
- Point the timing light at the marks indicated in the chart and illustrations. With the engine at idle, timing should be at the specification given in the specifications chart located earlier in this section.
- If the timing is not at the specification, loosen the pinch bolt at the base of the distributor just sufficiently so that the distributor can be turned. Rotate the distributor to advance or retard the timing as required. Once the proper marks aligned (as seen with the timing light), ignition timing is correct.
- Stop the engine and tighten the pinch bolt. Start the engine and recheck the timing to be sure it did not change while the bolt was tightened.
- Stop the engine; disconnect the tachometer and timing light. Connect the vacuum line(s) to the distributor vacuum unit.
DUAL POINT DISTRIBUTOR
A dual point distributor is offered as an option on some Corolla models (sold outside of California for 1975-77). To adjust the dual point system, proceed as follows:
- Adjust the timing for the main set of points as previously outlined in the Single Point section.
- Use a jumper wire to ground the terminal on the thermoswitch connector after removing the connector from the thermoswitch. The thermoswitch is threaded into the intake manifold and is connected to the dual point system relay. Be careful not to confuse it with any of the emission control system switches which are connected to the computer.
- Check the timing with a light as described earlier under the single point procedure, the timing should be approximately 3 degrees before top dead center (BTDC).
- If the timing is off, connect a dwell meter to the negative side of the coil, and adjust the sub-points so that the dwell angle is 52 degrees. The sub-points are adjusted in the same manner as the main points.
- Remove the test equipment and reconnect the thermoswitch.