Subaru used an 1.8-liter multi-point fuel injection four-cylinder engine on its 1996 Impreza. The engine has an ignition timing of 20 degrees, and it can be adjusted with a few tools if you have minimal mechanical skills. Poor ignition timing can disrupt the operation of your car, so you should routinely check and adjust the timing to ensure top performance.
Park the Subaru in an area away from traffic. Turn on the engine. Shut off all accessories and equipment.
Place wheel chocks under the front and back tires of your car. Apply the emergency brake. Put the transmission in neutral if you have an automatic, or in low gear if you have a manual transmission. Rev the engine, and allow it to reach a warm idle speed of 750 rpm.
Ensure that the emergency brake it firmly engaged. Open the hood, and engage the power train control module by turning the warm idle speed option on to keep the engine warm.
Attach the timing light to the car's battery. Connect the red clip to the positive terminal before you connect the black clip to the negative terminal. Attach the timing light clamps to the number one spark plug wire.
Shine the timing light on the pulley connected to the engine's main crankshaft. Observe where the timing mark falls by looking at the main crankshaft pulley and comparing the timing to the degree tab on the front of the engine. You should now be able to determine the current ignition timing. End all operations if you are satisfied with the current ignition timing. Otherwise, go to Step 6.
Find the distributor lock-down bolt, which is usually located at the base of the distributor housing. Loosen the bolt with a wrench, disconnect the distributor vacuum hose from the distributor housing and plug it into the electronic spark computer. Ground the carburetor switch with jumper cables by placing the red clamps on the switch and the black clamps on the ground.
Rotate the distributor by hand until the timing mark on the main crankshaft pulley aligns with the desired degree tab at the front of the engine. Twenty degrees is the factory recommended ignition time for the 1996 Subaru Impreza.
Unplug the distributor vacuum hose from the electronic spark computer, reconnect it to the distributor housing and tighten the lock-down bolt. Remove all of the timing light connections and the jumper cables. Disengage the power train control module, and close the hood to your engine. Put the transmission in park, and remove the wheel chocks.
