With the engine at operating temperature and the engine idling, the ignition advance angle will be approximately 6 to 8° of crank angle rotation before Top Dead Center. The ignition coil trace is used as a trigger to capture the waveform and to reference cylinder position. The table below shows the signal being displayed on each channel:ġ-Yellow-Ignition coil cylinder 1 control Image 2 presents a waveform that shows a trace at idle with 0 percent actuation of the exhaust solenoid. Using an oscilloscope the technician can view the actual change in camshaft position with respect to the crankshaft and the camshaft which hasn’t been actuated. See image 1 below:ĭuring actuation of the solenoid valve it can be seen that the engine speed dropped to 587 revolutions per minute (RPM), the electronic throttle control system increased the engine speed to prevent a stall so the engine speed increased to 812 RPM before stabilizing at 737 RPM when the actuator test finished. During the functional test, the technician is presented with data. For the purpose of this article the exhaust camshaft timing control solenoid has been actuated. This particular Toyota Auris (Corolla) with a 1NR-FE engine has variable valve timing on both intake and exhaust camshafts. To demonstrate let’s take a look at an example. Using an actuator test, a technician can actuate a variable valve timing solenoid and observe a change in the audible note of the engine and/or a change in engine speed. By altering when the valves open and close you can optimize the performance of the engine. The purpose of variable valve timing (VVT) is to help increase the engine’s volumetric efficiency and limit the exhaust gasses produced by the vehicle. Such conditions can be difficult to diagnose without the correct equipment. Sometimes a vehicle will suffer from driveability issues and fault codes relating to valve timing.
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