Toyota Crown 1G-FE (1999): Checking and Adjusting Ignition Timing with a Timing Light

Part numbers are from the manufacturer's original catalogue. Check them against your VIN before ordering.

• timing light (inductive preferred)
• jumper wire
• 12 mm or 14 mm wrench for the distributor mounting bolts
• tachometer
• chalk or white paint
• shop rags

1. Warm the engine to operating temperature (the cooling fan should cycle on at least once). Turn off all accessories: lights, heated features, A/C. With an automatic transmission, keep the shifter in N, apply the parking brake, and chock the wheels.
2. Locate the timing marks: the lower timing belt cover (at the front) has an angle scale, and the crankshaft pulley has a notch or groove. Clean them and mark the pulley notch and the 10° mark on the scale with chalk.
3. Connect the tachometer and timing light according to the instrument's instructions: attach the inductive pickup to the No. 1 cylinder spark plug wire (the one closest to the timing belt end of the engine), observing the correct polarity on the power leads.
4. Find the diagnostic connector in the engine compartment (a block with terminal labels, usually near the right or left strut tower, under a cover). Use the jumper wire to connect terminals TE1 and E1. The terminal names and locations are shown on the connector cover or on the sticker under the hood. This puts the ECU into fixed-timing mode without automatic correction.
5. Check the idle speed: it should be roughly 650-750 rpm. If it is far off, there is no point in measuring timing — first find the cause (throttle body, IACV, vacuum leak).
6. Aim the timing light at the marks. The notch on the pulley should line up with the 10° BTDC mark. Tolerance is ±2°.
7. If the timing is out of tolerance: shut off the engine and loosen the distributor mounting bolts (do not remove them completely). Start the engine and slowly rotate the distributor housing: turning it in the direction of rotor rotation decreases the advance, and turning it against rotation increases it. Adjust until the mark lines up with 10°.
8. Tighten the distributor mounting bolts (torque is usually 13-20 N·m (10-15 lb-ft); for the exact value, follow the manufacturer's specification). Recheck the timing with the timing light, since tightening can shift the housing.
9. Remove the jumper from TE1-E1 and confirm that the idle timing has changed (in normal operation, actual timing is more advanced than base timing, usually around 10-20° BTDC). This is normal — the ECU has returned to automatic control.
10. Shut off the engine and disconnect the instruments. If the Check Engine light was on, check for stored trouble codes and, if needed, clear them by disconnecting the battery terminal for a few minutes.

• Be careful when working around a running engine: keep hair, clothing, and wires away from the belt and fan
• Do not touch the high-tension wires with bare hands
• If the marks on the pulley and cover are hard to see, or if the pulley has slipped on the hub (so the mark no longer matches the actual piston position), the result will be wrong; in that case it is better to take the car to a repair shop
• Verify the exact timing value and diagnostic connector terminals against the sticker under the hood, as they may differ between markets