Tools Needed:
* Timing light: Essential for reading the timing.
* Socket wrench and extensions: To access the distributor.
* Wrench for distributor hold-down bolt: Often a 10mm or 12mm.
* Screwdriver: For adjusting the distributor (if needed).
* Owner's Manual or Repair Manual: Absolutely crucial for specific timing specifications.
Procedure:
1. Warm up the engine: Run the engine until it reaches normal operating temperature. This is important for accurate readings.
2. Locate the timing marks: Find the timing marks on the crankshaft pulley and the timing cover. The crankshaft pulley mark usually has a pointer or notch. The timing cover will have a series of marks indicating degrees before and after Top Dead Center (TDC). Your repair manual will show you exactly where these are located.
3. Disconnect the negative (-) battery terminal. This is a vital safety precaution to prevent accidental short circuits.
4. Find the number 1 cylinder. This is typically found using a method described in your repair manual (often involving feeling for piston movement at the spark plug hole). Make absolutely certain cylinder #1 is at Top Dead Center (TDC) on the compression stroke. This is crucial for accurate timing. Your repair manual will outline this procedure, typically looking for a specific alignment of both the crankshaft and camshaft marks.
5. Connect the timing light: Connect the timing light to the number 1 spark plug wire and clip the ground to a good ground point on the engine block.
6. Start the engine: With the timing light connected, start the engine.
7. Read the timing: Point the timing light at the crankshaft pulley. The light will illuminate the timing marks, showing the engine's timing.
8. Compare to specification: Your repair manual will give the correct timing specification for your engine at idle (usually around 5 degrees BTDC – Before Top Dead Center, but this can vary slightly depending on the year and model).
9. Adjust the distributor (if necessary): If the timing is off, carefully loosen the distributor hold-down bolt. Rotate the distributor slightly to adjust the timing to the specified value. Only make small adjustments. Re-tighten the distributor hold-down bolt and re-check the timing with the timing light.
10. Reconnect the negative battery terminal.
Important Considerations:
* Vacuum advance: The timing should be checked with the vacuum advance disconnected and plugged. Your manual will explain how to do this. After adjusting the timing, reconnect the vacuum advance.
* Initial timing vs. total timing: You're adjusting the *initial* timing here. The vacuum advance and centrifugal advance systems will add to the total timing at higher RPMs.
* Professional help: If you're uncomfortable performing this procedure, it's best to take your vehicle to a qualified mechanic. Incorrect timing can cause serious engine damage.
This information is for guidance only. Always consult your 1989 Toyota Pickup's repair manual for the exact procedures, specifications, and safety precautions specific to your vehicle. Failure to follow the correct procedures can lead to engine damage.
