See Figures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12
Electronic ignition systems offer many advantages over the conventional breaker points ignition system. By eliminating the points, maintenance requirements are greatly reduced. An electronic ignition system is capable of producing much higher voltage which in turn aids in starting, reduces spark plug fouling and provides better emission control.
In 1977, certain models made for California came equipped with electronic ignition. In 1978, Toyota decided to make electronic ignition standard equipment on all models and that same basic system is still used on trucks today.
The system Toyota uses consists of a distributor with a signal generator, an ignition coil and an electronic igniter. The signal generator is used to activate the electronic components of the igniter. It is located in the distributor and consists of three main components; the signal rotor, the pick-up coil and the permanent magnet. The signal rotor (not to be confused with the normal rotor) revolves with the distributor shaft, while the pick-up coil and the permanent magnet are stationary. As the signal rotor spins, the teeth on it pass a projection leading from the pick-up coil. When this happens, voltage is allowed to flow through the system, firing the spark plugs. There is not physical contact and no electrical arcing, hence no need to replace burnt or worn parts.
Service consists of inspection of the distributor cap, rotor and the ignition wires; replacing them as necessary. In addition, the air gap between the signal rotor and the projection on the pick-up coil should be checked periodically.
AIR GAP ADJUSTMENT
See Figures 13 and 14
- Remove the distributor cap as detailed earlier. Inspect the cap for cracks, carbon tracks or a worn center contact. Replace it if necessary, transferring the wires one at a time from the old cap to the new one.
- Pull the ignition rotor (not the signal rotor) straight up and remove it. Replace it if the contact are worn, burned or pitted. Do not file the contacts.
- Turn the engine using a socket wrench on the front pulley bolt until the projection on the pickup coil is directly opposite the signal rotor tooth.
- Get a non-ferrous (paper, brass, or plastic) feeler gauge of 0.30mm, and insert it into the pick-up air gap. DO NOT USE AN ORDINARY METAL FEELER GAUGE! The gauge should just touch either side of the gap. The permissible range is 0.20-0.40mm.
The air gap on all 1987-88 engines is NOT adjustable. If the gap is not within specifications, the distributor must be replaced.
- If the gap is either too wide or too narrow, loosen the two Phillips screws mounting the pick-up coil onto the distributor base plate. Then, wedge a screwdriver between the notch in the pick-up coil assembly and the two dimples on the base plate, and turn the screwdriver back and forth until the pick-up gap is correct.
- Tighten the screws and recheck gap, readjusting if necessary.