How to Set the Ignition Timing on Carsby Contributing WriterUpdated June 12, 2017
Gasoline burns relatively slowly. It is not the explosion we all imagine, but a slower, controlled burn. As the fuel burns in a car, the hot gases expand with an increasing pressure until the piston is forced down the cylinder. To get the maximum power and complete combustion, the slow-burning fuel is ignited before the piston actually reaches top dead center. This is called base ignition timing. Setting base ignition timing on a Honda car is relatively easy to do.
Under The Hood:
- How to Set the Ignition Timing on a 96 Chevy Astro
- How to Set Ignition Timing on a Civic
- How to Set the Ignition Timing in a 99 Honda Civic
- How to Set the Ignition Timing on a 1992 GM 5.7 Truck
Start your vehicle and allow it to reach a normal operating temperature. Turn the air conditioner off.
Apply the parking brake and block the wheels so the van remains stationary. If you have an automatic transmission, put the van in Park, and if you have a manual transmission, put it in Neutral.
Remove the instrument panel support braces from each side of the engine cover, using a screwdriver. Loosen the upper retaining screws on the engine cover. These screws can only be loosened, and not removed, because they are captured in the brackets. Unlock the two latches on the bottom of the engine cover and remove it from the vehicle.
Bypass the electronic spark timing before checking the timing. Remove the single tan wire with a black stripe connected to the distributor. Unplug the connector, but do not unplug the 4-wire harness cover at the distributor.
Find the timing marks at the front of the engine. It is more difficult to see these components in an Astro Van because of the tight fit of components in the engine compartment. The crankshaft pulley or vibration damper has a notch in it and a small metal plate with notches and numbers is attached to the timing cover. Clean the plate with solvent, if necessary, so you can see the numbers. .
Use chalk to mark the notch or groove in the pulley or vibration damper. Highlight the notch or point on the timing plate that corresponds to the correct ignition timing specification. You will find this on the Emission Control Information label under the hood of the van.
Hook up an inductive pick-up timing light according to the manufacturer's directions. Make sure the timing light wires are not near the drivebelts or fan and then start the engine.
Allow the idle to stabilize and then point the timing light at the timing marks. Because of the tight fit of the components in the engine compartment of an Astro van you may need to push the radiator hose out of the way. Be aware of moving components, and keep both the timing light and yourself clear of them.
Notice the mark you made on the pulley/vibration damper. It should appear stationary. If it is aligned with the specified point on the timing plate, your timing is set correctly. If the marks are not aligned, you will need to adjust the timing.
Loosen the distributor hold-down bolt and turn the distributor slowly until the marks are aligned. Access to this bolt is limited and you may need a special distributor wrench to turn it.
Tighten the bolt. Recheck the timing. Turn off the engine and remove the timing light.
Reconnect the wire harness connector. Clear any trouble codes.
Items you will need
Inductive timing light
Prepare for the timing adjustment. Start the engine and let it run until it reaches operating temperature. While the engine is running, remove the passenger-side kick panel and locate the two-wire connector located behind and just above it. It may take some digging to find it but it is there. When the engine temperature reaches operating temperature on the gauge, shut off the engine and install a jumper wire into the connector. This turns off the computerized timing and allows the engine to run in base timing.
Attach a timing light to the battery and the number one spark plug wire. The number one spark plug wire is the one located closest to the front of the motor. Some timing light pick-ups (the part that attaches to the spark plug wire) have an arrow indicating which side should face the spark plug. Make sure this arrow points at the spark plug.
Start the engine, and aim the timing light at the pointer on the front of the timing cover near the crankshaft pulley. Squeeze the trigger to start the strobe, and look at the mark on the pulley and timing cover. They should line up. There are 3 marks positioned close together. The middle mark is 16 degrees before top dead center, and this is the base timing called for by the manufacturer. If the marks do not line up, loosen the two distributor bolts attaching the distributor to the cylinder head, and rotate the distributor while watching the timing marks. When the mark on the pulley lines up with the pointer, tighten the distributor bolts, and turn off the engine.
Disconnect the jumper wire on two-wire connector. Reinstall the kick panel and test drive the car to verify the adjustment.
Items you will need
Turn on the Civic and allow the engine to run for 10 minutes. Then turn off the car.
Pry off the side panel in the front passenger footwell in the interior of the car.
Place a jumper wire into the two-wire connector that is underneath the panel. This will override the computerized timing of the vehicle and allow you to adjust the ignition timing.
Open the hood and attach the timing light to the Civic's battery. Attach the black timing light cable to the black battery terminal and attach the red timing light cable to the red battery terminal.
Attach the third timing light cable to the spark plug one cable, so that the arrow on the timing light is facing the number one spark plug.
Turn on the engine and point the timing light at the timing cover.
Loosen the two 10 mm bolts on the distributor cap.
Turn the distributor cap slowly as you look at the timing cover with the timing light flashing onto it. When the middle mark on the pulley lines up with the mark on the timing cover, stop turning the distributor cap.
Turn off the engine.
Tighten the bolts on the distributor cap, then remove the timing light and the jump wire. Replace the panel in the passenger footwell.
Items you will need
Unscrew the wing nut that attaches the air cleaner to the throttle body. Unplug the vacuum lines under the air cleaner and lift the air cleaner off the throttle body. Plug the disconnected vacuum lines with golf tees.
Start and warm the engine until normal idle speed occurs. Attach the timing light to the battery and the front spark plug wire on the driver side of the engine. Turn the engine off. Unplug the the single wire timing connector found taped to the wiring harness that runs along the back of the fire wall.
Loosen the distributor by loosening the 9/16-inch bolt on the hold down bracket at the base of the distributor housing. Start the engine. Aim the timing light at the timing pointer on the front of the timing cover and rotate the distributor to adjust timing. Align the mark on the harmonic balancer with the 12 degrees notch on the timing pointer. Tighten the distributor hold down bracket bolt.
Turn off the engine and reinstall the air cleaner. Plug the timing connector back in and test drive the vehicle.
Items you will need