How to Set the Timing on a 1985 Plymouth Horizon

The 1985 Plymouth Horizon was built with a 1.6-liter, four-cylinder engine. The ignition timing of the internal combustion engine determines when a spark will fire in the engine. The ignition timing for the 1985 Plymouth Horizon is 12 degrees. You can adjust the ignition timing to make sure it is accurate or you can adjust it to your preference. Be careful when working around moving engine parts and don't deviate too far from the factory-recommended 12 degrees when adjusting the ignition timing.

Tools Used: Timing light, Wrench, Wheel chocks

Set Timing

Park your car in an area with space to work on the engine. Let the engine idle and turn off all accessories including the radio and air conditioning/heat.

Use wheel chocks to chock the wheels of your car for safety purposes. Put the transmission in neutral and firmly set the emergency brake. Bring the engine to an idle speed of 850 rpm if you have an automatic transmission and 1,000 rpm if you have a manual transmission.

Exit the vehicle with the emergency brake firmly engaged and open the hood of your car.

Attach the red clip of the timing light to the positive terminal of the car battery. Attach the black clip of the timing light to the negative battery terminal. Then, connect the timing light to the number 1 spark plug and the main crankshaft pulley.

Observe the timing mark on the pulley to check the ignition timing. Continue on to the next step if you would like to adjust the timing. Otherwise, if the timing is acceptable, disconnect the timing light cables, close the hood and remove the wheel chocks.

Loosen the distributor lock-down bolt with a wrench and then disconnect the distributor vacuum hose from the distributor housing. Plug the distributor vacuum hose into the electronic spark computer and ground the carburetor switch with jumper cables.

Rotate the distributor until the timing mark on the pulley falls to 12 degrees.

Unplug the distributor vacuum hose from the electronic spark computer and reconnect it to the distributor housing. Tighten the distributor lock-down bolt with your wrench and remove the jumper cable from the carburetor switch. Remove the timing light cables and close the hood. Remove the wheel chocks from your wheels.