How to set Pontiac Fiero Ignition Timing

*Never ground the TACH terminal; serious module and ignition coil damage will result.
*Do not come in contact with any spark plug wires while the engine is running.
(Ignition system produces 20,000-30,000 volts while the engine is running.)

The ignition timing for the Direct Ignition System (DIS) is controlled by the electronic control module ECM and is NOT adjustable.

Adjusting HEI / EST Ignition Systems timing

1. Connect a timing light to the No. 1 spark plug wire according to the light manufacturer's instructions. Do not pierce the spark plug wire to connect the timing light.
2. Follow the instructions on the under-hood engine decal for checking the ignition timing. These reflect the latest production changes for your vehicle.
3. Disconnect the 4 terminal connector at the distributor.
4. Start the engine and run it at idle speed.
5. Aim the timing light at the degree scale just over the harmonic balancer.
6. Adjust the timing by loosening the securing clamp and rotating the distributor until the desired ignition advance is achieved, then tighten the clamp.
7. Loosen the distributor retaining bolt. On some engines its necessary to slide the clamp back slightly. Do not remove the retaining bolt.
8. To advance the timing, rotate the distributor opposite the normal direction of rotor rotation. Retard the timing by rotating the distributor in the normal direction of rotor rotation.