The crankshaft sensor on the Ford 4.6-liter V-8 engine uses a magnetic pulse to send voltage proportionate to engine speed to the computer. The sensor is a mounted trigger wheel with 35 teeth. There is a "missing" tooth, which is used as the sync signal to fire the coil. The computer also uses a signal from the crankshaft sensor to determine whether one or more cylinders are misfiring by measuring rapid deceleration between the teeth. The connector is a 12-wire connector.
Check the waveform signature while cranking the engine by attaching the red lead on the power graphing meter to the crankshaft sensor positive wire (sixth wire from the left) and the black lead to a known good ground.
Press "Yes" on the meter. Have a friend crank the engine over while you watch the graph. The signal should look like several Vs connected at the top, and except for the second V, should be approximately the same size.
Check the AC voltage by connecting the red lead to the crankshaft positive (sixth wire from the left) and the black lead to a known good ground. While cranking the engine, you should have 0.5VAC. If the vehicle starts, the ACV should be approximately 1.5 to 2 volts. As you increase rpm, the voltage should increase smoothly. At 2,500 rpm, voltage should be about 4.5 volts.
