Test procedure for hall sender and knock sensors?
05-13-2010, 08:06 PM
#1
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Test procedure for hall sender and knock sensors?
Hi folks,
I've seen a number of threads where it's mentioned that EZK will retard timing by 6 degrees if it detects a fault with the hall sender or either of the knock sensors.
Is it as simple as verifying idle timing to see whether things are OK here, or does the idle retard only happen at higher levels of advance and load?
Is there another way to verify these components, without going to a spanner, etc?
Thanks,
Paul
I've seen a number of threads where it's mentioned that EZK will retard timing by 6 degrees if it detects a fault with the hall sender or either of the knock sensors.
Is it as simple as verifying idle timing to see whether things are OK here, or does the idle retard only happen at higher levels of advance and load?
Is there another way to verify these components, without going to a spanner, etc?
Thanks,
Paul
05-13-2010, 08:39 PM
#2
Chronic Tool Dropper
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No good way that I know of short of a Hammer or Spanner. The Spanner will get an adapter harness for your car, and then you should be able to see if the EZK and LH brains like the signals coming from those sensors. The timing retard is subtle, BTW. I found with a Spanner sweep that the rear knock sensor was bad, and the Hall sensor was intermittent. I would have found the knock sensor eventually, since the cable was pulled open. But the Hall sesnor issue was caused by a poorly routed FOE wiring harness where it loops over the right front lift hook, the hook that also serves as a connector support. Rerouted the cable correctly and that Hall error went away. Subtle change didn't show up as a performance change, since I drive the car pretty gently. Fuel economy improved noticeably though.
05-13-2010, 09:14 PM
#4
To test whether the Hall Sensor or Knock Sensors are "Bad" requires a Spanner, Hammer or DT928 diagnostonic tools.
My Hall Sensor was showing a fault and if you don"t have an Oscilliscope to check the wave form of the sensor there is a method using an alalogue multi meter. Removed my hall sensor, (a little difficult as it is located just above the forward end of the RHS of the cylinder cam cover just behind the cam shaft pulley on the casing timing belt casing. You will need small fingers and they also need to be double jointed), cleaned it, checked the wiring for continunity and resistance between the wires.
To test, connected the analogue multi meter after selecting the dc voltage and passed a metal object through the magnetic field of the pick-up head. IIRC the hall sensor produces a square wave form has a magnitude of around 5 volts, so if the multi-meter needle pointer jumps then you have a signal and it should be OK.
If you do a Google search on Hall Sensor tests you should find this method.
Reinstall the Hall Sensor, re-route the wires as described by Dr Bod and it should be OK, that is if the three pin connector has not broken up which will require a new connector to be fitted. As a temporary/permanent measure you can use rubber welding tap to repair the connector if it is still servicable.
The knock sensors are "pick-up microphones" that pick up any pre-ignition within the cylinders when the timing is advance by the CPU's. The test for these is to again use a Hammer, Spanner or DT928 diagnostic tools to check whether they are faulty and also to count the knocks over a 10,000 revolution count and the recommended knock count should not exceed 25.
My method of R&M for the knock sensors is to check the wiring for continunity and also the resistance between the each wire and the shielding wiring and the connections to the plug. In addition I have added an extra covering over the knock sensor wiring to try and preclude any stray knock type signals being picked up causing the timing to be retarded.
If you inspect the knock sensors you usually find that the microphone head has broken up due to the excessive heat under the intake manifold. If you knock the plug, as has usually hardened it falls to pieces. New connector can be purchased, however, the heads cannot be replace unless you buy a new total replacement unit. I have developed a new head covering myself and this works satisfactorily and I have no faults recorded on the knock sensors and the knock count is satisfactory.
Tails 1990 928S4 Auto
My Hall Sensor was showing a fault and if you don"t have an Oscilliscope to check the wave form of the sensor there is a method using an alalogue multi meter. Removed my hall sensor, (a little difficult as it is located just above the forward end of the RHS of the cylinder cam cover just behind the cam shaft pulley on the casing timing belt casing. You will need small fingers and they also need to be double jointed), cleaned it, checked the wiring for continunity and resistance between the wires.
To test, connected the analogue multi meter after selecting the dc voltage and passed a metal object through the magnetic field of the pick-up head. IIRC the hall sensor produces a square wave form has a magnitude of around 5 volts, so if the multi-meter needle pointer jumps then you have a signal and it should be OK.
If you do a Google search on Hall Sensor tests you should find this method.
Reinstall the Hall Sensor, re-route the wires as described by Dr Bod and it should be OK, that is if the three pin connector has not broken up which will require a new connector to be fitted. As a temporary/permanent measure you can use rubber welding tap to repair the connector if it is still servicable.
The knock sensors are "pick-up microphones" that pick up any pre-ignition within the cylinders when the timing is advance by the CPU's. The test for these is to again use a Hammer, Spanner or DT928 diagnostic tools to check whether they are faulty and also to count the knocks over a 10,000 revolution count and the recommended knock count should not exceed 25.
My method of R&M for the knock sensors is to check the wiring for continunity and also the resistance between the each wire and the shielding wiring and the connections to the plug. In addition I have added an extra covering over the knock sensor wiring to try and preclude any stray knock type signals being picked up causing the timing to be retarded.
If you inspect the knock sensors you usually find that the microphone head has broken up due to the excessive heat under the intake manifold. If you knock the plug, as has usually hardened it falls to pieces. New connector can be purchased, however, the heads cannot be replace unless you buy a new total replacement unit. I have developed a new head covering myself and this works satisfactorily and I have no faults recorded on the knock sensors and the knock count is satisfactory.
Tails 1990 928S4 Auto
05-13-2010, 09:38 PM
#5
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The DT999 is complemented by the PDT999 diag system..............perhaps theres an owner nearby that could run your car through all tests.
The cable harness routing is depicted in one of Dwaynes classics:
The cable harness routing is depicted in one of Dwaynes classics:
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05-14-2010, 08:59 PM
#9
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Its not really a true HALL sensor like that manual states. More of a VR sensor.
Engine cranking, connector back-probed, look for a signal like this:
Engine cranking, connector back-probed, look for a signal like this:
Last edited by toofast928; 12-09-2012 at 10:54 PM.
05-15-2010, 12:14 AM
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