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Waggin
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 Posted: Tue Jan 18, 2005 10:52 pm Post subject: Crank Position Sensor (CKP) |
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Hey Guys,
Does anyone know what sort of sensor the CKP is on the 4L Falcons? I know it creates a sine wave with for a falling edge trigger- but would I be correct in assuming its a magnetic sensor?
The workshop manual fails to mention that detail, despite informing the CMP is a Hall sensor. MEh!
Cheers  |
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kosmond
Fordmods - Getting Side Ways
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| Posted: Wed Jan 19, 2005 12:07 am Post subject: |
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Found this on the opp site is it any help
Crankshaft/Camshaft sensors
These sensors report shaft speed and position to the ECM. There are three different types of CKP and CMP sensors. The inductive sensor is a permanent magnet with a coil of wire around it, positioned close to a toothed wheel on the shaft. As each moth passes the magnet, it disturbs the magnetic field and a sine-wave voltage is induced in the coil. The computer interprets the frequency of the sine wave as rpm. A specific position, such as TDC, can be referenced by making the gap between two of the teeth different from the rest, making the sine wave signal different at that location. The distance of the sensor from the toothed pick-up wheel is critical and often adjustable. The inductive sensor is simple and tolerant of harsh environments, but the other two types of sensor are usually inside the distributor or dedicated housing. The Hall effect sensor has a permanent magnet mounted next to a semi-conductor chip that has a current passing through it. A metal wheel with tabs is mounted so that the tabs pass between the magnet and the chip. As the wheel rotates, the interruption of the magnetic field changes the current flow through the chip. The resulting frequency signal can represent either speed or position, and is commonly used for both.
The other active sensor type is a photo diode, using an LED to produce light, another type of diode that detects light, and a wheel with slots or holes passing between them. The openings in the wheel can represent degrees of rotation or any other desired reference. On certain Nissan systems, the distributor contains one wheel with three sets of slots, LEDs and detectors that read rpm, camshaft position and cylinder number one. On many Asian vehicles, the loss of a cylinder reference signal will not stop the engine if it is already running, but the ECM needs both reference and rpm signals for starting.
On most Asian OBDII systems, there is a dedicated sensor that reads crankshaft speed for misfire detection, usually an inductive type mounted right on the block. The resistance of inductive sensors can usually be tested with a DVOM if you can find the specification. For the other sensors, the presence of a signal can often be detected with a DVOM while the engine is running or cranking, but the quality of the signal can only be tested `live' by back-probing the signal wire with a scope.
The sensors described here are all an engine needs for basic fuel quantity and spark timing; air mass, crankshaft speed and camshaft position. In future editions of this series, we'll look at other devices used to control fuel trim, ignition advance, valve timing, intake manifold tuning valves, traction control, emission control and anything else managed by the ECM. Then you'll know everything the ECM knows, and more.
Line drawing illustrations courtesy of Autodata Publications Inc., who also provided much of the research material for this article.
COPYRIGHT 1999 Cahners Publishing Company
COPYRIGHT 2000 Gale Group
http://www.fordforums.com/showthread.php?t=9910
thanks ppl |
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Waggin
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| Posted: Wed Jan 19, 2005 12:25 am Post subject: |
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Excellent. I was leading toward Magnetic.
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Disco Frank
Fordmods Junkie
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| Posted: Wed Jan 19, 2005 10:43 am Post subject: |
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| thats a good read!!! cheers for that |
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