How to Adjust the Timing in a Pontiac Bonneville

The Pontiac Bonneville has been around for generations and many models require an adjustment to the timing during a tune up or changing the timing belt. This guide covers adjusting the timing in a Pontiac Bonneville model with non-ESC ignition systems. Pontiac Bonneville models with ESC or PCM ignition controls do not require adjustment. Adjusting the timing on a Pontiac Bonneville requires special tools and mechanical knowledge.

Difficulty: Moderately Challenging

Instructions

Things You'll Need:

• Timing light
• Tape or golf tee
• Wrenches

1. Run the engine until it has reached normal operating temperature and turn it off. Connect the timing light to the battery if necessary and then to the number one ignition wire located at the front driver's side of the engine.

2. Locate the crankshaft pulley at the bottom front of the engine and clean off any dirt and grime to expose the timing notches. Bump the ignition if the marks are at the bottom by engaging the starter momentarily without starting the car.

3. Disconnect the vacuum hose on the distributor and plug it with tape or a golf tee. Start the engine and let it idle for one minute. Point the timing light at the crankshaft pulley and determine the amount of adjustment required.

4. Loosen the mounting bolts on the distributor and turn it slowly until the timing mark on the crank pulley matches the middle line on the timing light. Tighten the distributor mounting bolts and recheck the timing.

5. Turn off the engine and remove the timing light. Reconnect the number one ignition wire and replace the vacuum hose on the distributor. Start the car and allow it to idle for 5 minutes.

Tips & Warnings

• Never pierce a spark plug wire to hook up the light. Once the insulation is broken, the voltage will seek a ground and cause the engine to misfire.

Resources

• Timing lights and accessories

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