Knock sensor monitoring
06-17-2001, 02:31 PM
#1
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Knock sensor monitoring
Can anyone recommend a way to visually monitor any knocking on a '95 993 pre-OBDII using existing knock sensors? I heard that one of the OBD pins delivers the knock signal directly from the ECU. Has anyone rigged it to an indicator (like a giant red light which comes and stays on until reset)?
Thanks for the feedback.
Thanks for the feedback.
06-17-2001, 08:14 PM
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Pin 11 (Ye/Gr) in connector X4/2 under your drivers seat contains the 'knocking yes/no' output from the brain.
If I recall right, it reads 5 volts when not knocking and pulls down to ground when it is.
We usually watch this pin on a handheld oscilloscope, but I bet you could probably use one of those 'noid lights' that they use for testing fuel injectors.
The signal is so fast that a standard light or led probably wouldn't light up unless the engine was coming apart.
You could also build a simple circuit with a latch that would output to a light, as you said, then stay on till you reset the latch.
If I recall right, it reads 5 volts when not knocking and pulls down to ground when it is.
We usually watch this pin on a handheld oscilloscope, but I bet you could probably use one of those 'noid lights' that they use for testing fuel injectors.
The signal is so fast that a standard light or led probably wouldn't light up unless the engine was coming apart.
You could also build a simple circuit with a latch that would output to a light, as you said, then stay on till you reset the latch.
06-17-2001, 08:36 PM
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Originally posted by Protomotive:
<STRONG>Pin 11 (Ye/Gr) in connector X4/2 under your drivers seat contains the 'knocking yes/no' output from the brain.
If I recall right, it reads 5 volts when not knocking and pulls down to ground when it is.
We usually watch this pin on a handheld oscilloscope, but I bet you could probably use one of those 'noid lights' that they use for testing fuel injectors.
The signal is so fast that a standard light or led probably wouldn't light up unless the engine was coming apart.
You could also build a simple circuit with a latch that would output to a light, as you said, then stay on till you reset the latch.</STRONG>
<STRONG>Pin 11 (Ye/Gr) in connector X4/2 under your drivers seat contains the 'knocking yes/no' output from the brain.
If I recall right, it reads 5 volts when not knocking and pulls down to ground when it is.
We usually watch this pin on a handheld oscilloscope, but I bet you could probably use one of those 'noid lights' that they use for testing fuel injectors.
The signal is so fast that a standard light or led probably wouldn't light up unless the engine was coming apart.
You could also build a simple circuit with a latch that would output to a light, as you said, then stay on till you reset the latch.</STRONG>
