How to Align Dual Camshaft Timing?
2 Answers
The method for aligning dual camshaft timing is as follows: 1. First, check if the timing belt is installed incorrectly. Then inspect the wiring: The camshaft position sensor has 3 wires, which are the 5V power supply (with the ignition switch turned on), the sensor negative, and the output signal. Use a test light to check if the 5V power supply on the sensor positive is a weak connection. All 3 wires lead to the engine ECU. Disconnect the battery negative terminal and unplug the ECU connector. Use a multimeter to measure the resistance between these 3 wires from the sensor connector to the ECU connector. The resistance should not exceed 0.5Ω. Then check for any short circuits. 2. If the above checks are normal, connect one end of an LED test light to the sensor negative and the other end to the output signal (with the ECU, sensor, and battery negative terminal all properly connected). Start the engine, and the test light should flash.
Last time I helped my friend with the dual overhead cam timing on his old Japanese car, I realized the key to this job is aligning the marks. You first need to rotate the crankshaft to bring cylinder one to top dead center, aligning the small dot on the crankshaft pulley with the mark on the engine block. The camshafts also need to be locked in place with a special tool—like those on Toyotas, which have slots at the rear to prevent movement. The tension of the chain or belt must be adjusted properly, and the tooth count must be absolutely correct during installation. Finally, rotate the engine a few times to check for any abnormal noises. The whole process requires two people to cooperate—one turning the crankshaft while the other watches the cams. By the way, modern cars with VVT systems are even more complicated, so it's essential to follow the repair manual step by step to ensure everything is done correctly.
