crank position sensor testing

Discussion in 'Gen 1 & 2 - Emergency Issues - Help & Maintenance' started by tery, May 19, 2019.

  1. tery

    tery Silvia survived the purge- summer car

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    Hi Folks,
    Is there a way to test a crank position sensor off the car?? I didn't see any threads in that direction..
    thx
    T
     
  2. blk\blk90

    blk\blk90 SHO Member Supporting Member

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  3. NoSlo

    NoSlo GoldMember

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    [​IMG]

    You can first test for basic faults. Resistance from PIP pins to ground and power should measure over 10kohms. If it is shorted, the sensor or wiring has failed.

    The sensor has a digital converter - the hall effect device in the sensor is used to trigger a switching output. When there is no magnetic field, such as when the vane of the camshaft or crankshaft is blocking magnetic flux from the permanent magnet, the PIP output signal will be 12V, the battery voltage. If instead, there is no vane, and magnetic flux from a permanent magnet is held near the sensor in similar configuration and N-S alignment, the output will switch to zero volts.

    [​IMG]

    One can set up an apparatus that will power the CPS with battery voltage. Then create the pulses, via (edit) ferrous metal like the crank vane that interrupts the gap. Then see that the correct PIP signal output pulses are generated, perhaps with an oscilloscope instead of a test light or multimeter. If you don't get the expected output, you'd need to see that your methodology is correct with a known-good sensor.



    There are three crankshaft vanes per revolution, one for each spark pulse, so the pulse rate in normal operation is between 2400 (800 RPM) and 24000 pulses per minute - 40 to 400 pulses per second. Then we need to know if it would operate correctly on a car; the closer you can simulate the crankshaft vanes spinning, and even engine temperatures, the more likely you'll diagnose a good or bad one.
     
    Last edited: Jul 2, 2019
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  4. tery

    tery Silvia survived the purge- summer car

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    T H A N K You,
     
  5. EarlyBroncoGuy

    EarlyBroncoGuy New Member

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    I've ordered a crank sensor from a 2.3L in a '90 Ranger to compare with an SHO crank sensor and see what might need to be rewired to be able to use the Ranger crank sensor in an SHO. The Ranger sensor is very similar but has 2 slots, one for the PIP signal and one for the CID signal - the SHO sensor only has one slot, it generates the PIP signal and sends it to both the DIS and the ECU. The CID signal is generated from the cam sensor on SHO's.

    My theory is to find which wire on the Ranger sensor has the PIP signal on it, then take that signal, combine it to the 2 wires in the SHO harness, which will send it to the DIS and the ECU in an SHO. The CID signal will still be generated by the SHO cam sensor.
     
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  6. Mark Kreutzer

    Mark Kreutzer New Member

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    even with the wiring change, i still dont think it will read the gaps on the crank because there's that tiny lip between em and the ranger hall effect sensor/magnet stick out prob 1/8" more then the original, and since it mounts to the oil pump the options seem limited.
     
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  7. NoSlo

    NoSlo GoldMember

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    The majority of Ford crankshaft position sensors, especially 1996 and after, appear to be two-wire sensors without battery power or digital converter - they require a bias voltage of about 2 volts from the PCM, and put out 0.5V AC when pulsing. Completely incompatible.

    With similar wiring, the Ranger CKP has an integrated magnet in the center, and the sensor has two vane slots, each with its own output, with sensors on the top and bottom. This includes the sensor for DIS ignitions on 89-93 Mustang 2.3l, Ranger 2.3L 89-98, Mazda B2300: (Ford/Mazda parts E9TZ6C315A F07E6C315AC F0TZ6C315B, F0TZ6C351A F1TZ6C315A F1TZ6C351A, F4ZZ6C315A F4ZZ6C351A F4ZZ9C351A, ZZMO18082 F0TZ6C315C F27E6C315BA, ZZM018370 PC10 5S1744 SU221 CSS60)

    [​IMG]

    Here is testing this sensor:


    The 2.3L's two hall sensors have quite different timing outputs, as can be seen by the crankshaft hub vanes:

    [​IMG]

    It might be possible to cut off the bottom sensor, and use the top for both PIP outputs on the SHO, rewiring the connector. However if such a modified sensor was mounted by the two bolts, the gap would be far too wide. One of the two sensors probably responds to reverse N-S magnetic polarity. The signal conversion circuitry is probably the full length of the body, prohibiting this anyway (along with the different shape back).

    It is possible the SHO's dual PIP outputs are also two-sensors-in-one, not timed the same, side-by-side in the sensor body. There's no literature documenting if this is true, you'd literally have to crack open a bad SHO CKP to see how it is made, or hook a dual-trace oscilloscope up to both PIP outputs (which might be possible on a running car, by tapping wires near "DIS Module" and ECM, since the actual connector is buried.

    I might be able to do the latter, but time would be better spent cold-calling sensor manufacturers to ask WTF??

    Some other two-pin hall effect sensors, like Focus, Econoline 150 have a similar two-bolt body shape, but of course are electrically incompatible, and would take electronics to make the 0V-12V pulses.
     
    Last edited: Aug 4, 2019
  8. tery

    tery Silvia survived the purge- summer car

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    yeah...thank you very much
     
  9. NoSlo

    NoSlo GoldMember

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    A little more info I learned. The later two-wire crank sensors are what are called "variable reluctance" sensors (not hall effect), and work like ABS wheel sensors. They need many flywheel teeth to generate a crank speed signal, with a missing tooth to determine position. Cannot work with a vane type system.

    The digital-out Hall-effect sensor works similarly to the distributor PIP position sensors in the previous Ford TFI-IV ignition system. It has an analog-to-digital converter, outputting clean 12V or 0V. The hall effect sensor in our camshaft sensor and others also would have this required circuitry. The sensor circuitry is depicted on the left side of the image below:

    [​IMG]

    The circuitry on the left is likely all in one IC. The documentation for Standard Motor Product's sensors has fancy words like auto-adapting sensor logic, indicating their sensors (or whoever supplied Motorcraft and all others) may have more refined logic. That all different crank sensor part numbers and brands dried up at the same time lets us know there was only one real manufacturer of these sensors, or of the ICs needed.

    The 2.3 Ranger sensor, (or even 12V-out CID sensors, both which would have similar electronics), may also encounter supply issues, or even now could be limited to existing stock. Ranger sensors might be the only source of the 4-pin connector. Disassembling any for electronic parts looks like chipping electronics out of epoxy, or chemically decapsulating with methylene chloride or MEK (after testing how other ICs and circuit boards survive chemicals).

    There is simply no other sensor the right shape or with the correct vane orientation. There are Mitsubishi or Kia sensors that output 5V, with vanes turned 90 degrees.

    I've been contemplating how to remanufacture one, starting with epoxy resin molding and reinforcement, to reusing or rebuilding sensors, magnets, and electronics, and possibly an external enclosure for prototyping (fabbing a sensor-size SMT board would be an investment with challenges, as well as putting components under the water pump and heat), but can't really experiment with my only SHO. Sensing and timing of both the start and the end of the vane are important, as well as durability.
     
    Last edited: Jul 1, 2019
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  10. luigisho

    luigisho SHO Member

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    So we all have to switch to motec or something in the future with a different sensor? Hopefully begging can get a small run from somewhere.
    Zach is using an aftermarket setup for his beast. I wonder how the aftermarket sensor looks installed down there?
     
  11. EarlyBroncoGuy

    EarlyBroncoGuy New Member

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    I ordered a CPS for an '89 Ranger with a 2.3L and I finally got a chance to bench test it and compare it with an SHO CPS.

    1. Yes, it will physically bolt in place of the SHO cps, but it's tight. The wires exit the body of the sensor at a slightly different location than the SHO cps, which makes it difficult to fit into the slot. The mounting holes in the Ranger cps sensor are not slotted like the SHO cps, but they are larger than they need to be, which does allow some adjustment.

    2. The wiring connector is the same as a SHO cps, and the wires are in the same location within the connector as an SHO cps - Power, ground, and the 2 signal wires. On the Ranger cps, Red is Vbat (Vehicle battery power, 12v), Black is ground, Light Blue is the signal from the upper slot, and Gray is the signal from the lower slot.

    3. Connected to a power source, tested one at a time, the top slot acts just like the SHO cps - O volts with nothing in the slot, battery voltage when metal is in the slot. The bottom slot never changes state whether it's clear or blocked with metal. BUT...if you put something metal in the top slot and leave it there, THEN the bottom slot DOES change state when a piece of metal is inserted or removed from the bottom slot. In fact, it's so sensitive, you don't actually have to block the bottom slot with the shutter wheel or other piece of metal, if you bring it close enough to the sensor body (within a few millimeters) it will change state.

    Interesting, but not really useful, since the shutter wheel is so close to the cps sensor body when everything is installed on the engine the signal from the bottom slot won't change state, whether the vanes of the shutter wheel are within the slot or not. If a custom shutter wheel could be fabricated out of aluminum or strong plastic, with just enough ferrous metal in the same places as an original all steel shutter wheel, and the top slot permanently blocked with a piece of metal epoxied in place, in theory the Ranger cps could be persuaded to work in an SHO - provided the square wave signal generated from the sensor can be sent to the DIS module and the EEC, and the shape and amplitude of the signal will work as the PIP signal needed.

    Sounds like I need to dig my old storage O scope out of mothballs and blow the dust off, see if it still works, and do some more checking of signals.
     
  12. NoSlo

    NoSlo GoldMember

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    That is interesting behavior you observe, and is contradictory to the video above, where at 2:30 a feeler, inserted into either gap, switches the output of that PIP wire to 12 volts independently.

    The timing of the two vanes on the Ranger hub also contraindicate this operation.
     

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