Here is how to change the crank sensor
The Crankshaft Position Sensor (CKP) is mounted to the transmission bellhousing at the left/rear side of the engine block. Engine speed and crankshaft position are provided through the crankshaft position sensor. The sensor generates pulses that are the input sent to the powertrain control module (PCM). The PCM interprets the sensor input to determine the crankshaft position. The PCM then uses this position, along with other inputs, to determine injector sequence and ignition timing. The sensor is a Hall effect device combined with an internal magnet. It is also sensitive to steel within a certain distance from it.
On 4.0L 6-cylinder engines, the flywheel/drive plate has 3 sets of four notches at its outer edge. The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM. For each engine revolution there are 3 sets of four pulses generated.
The trailing edge of the fourth notch, which causes the pulse, is four degrees before top dead center (TDC) of the corresponding piston. The engine will not operate if the PCM does not receive a crankshaft position sensor input.
Friday, November 14th, 2008 AT 10:42 PM