All MS's are really 60 pin EECIV's with more open source electronics.
Down here in the Antipods, we are stuck between a mixture of the old European ignition retard systems, and the later Link ECU system controls, which are for Japanese turbos. Ford Turbo Falcons and Supercharged or turbo Holdens with GM engines, there is normally a reflash, so they use the stock stuff.
Most guys are using a Jaycar KC5444 knock sensor by John Clarke.
Early knock sensors...well, a knock sensor is a knock sensor, although the GM ones are more sensitive.
Later, the normal Ford 3 volt signal polling rate with a change to less than 3 volts being the descriminator has changed to the AFM type amp draw algorithim.
Just an Anolgue Digital "Do If True" ignition peal back.
Like the very bad 4.9 1-bbl feedback F150 truck system that screwed over so many shade trees who couldn't be frigged pullin the codes.
For the earlier resonant type, they are tuned to a particular engine’s knock frequency of interest.
Later KS's have a Power Spectural density determination, with a sampling cut off to sense the deap seated knock. Jaycar's does it that way, and so does GM now.
The combustion shock wave excites a characteristic frequency in the engine, which is typically in the 5000Hz–7000Hz range. Cylinder bore diameter and combustion chamber temperature are the main variables that affect this fundamental frequency. Variations in the fundamental frequency for a given engine configuration can be as much as ± 400 Hz in terms of combustion chamber design.
In terms of bore, the knock frequency can be greatly influenced.
Approximated using :
900/(Pi * r) where r = the radius of the bore in Sillymeters, um, millimeters.
Given a bore of 76mm the knock frequency will be 7540 Hz.
A bore of 3.7" or 93.98 mm, the knock frequency will be 6100 Hz
A fat bore Chevy or Ford with 4" bore, its down to 5600 Hz, with the very smooth combustion of a wedge head dragging its audiability down to a 5200 Hz threashold
Larger diameters and/or lower temperatures result in a lower fundamental frequency. Signals received by a remote sensor contain additional vibrational modes, which are structural resonances in the engine excited by the shock wave as it hits the cylinder wall. Typically, two to four additional frequency peaks are evident between the fundamental frequency and 20000 Hz. (Power Spectural Density determination)
Engine structure can have different higher vibrational modes. Sensor mounting location can affect which modes are detectableand the amplitude of each with respect to the background mechanical noise.
The later sensor’s all follow the Siemens or Bosch resonant frequency is above 20kHz with a wide pass-band to give a relatively flat response over a frequency range between 3kHz and 15kHz. This allows this sensor to monitor either the fundamental knock frequency or 1st harmonic for most engines.
The pinouts and use of MegaJolts EDIS6 means its a straight down the line FoMoCo.
On the stock Aussie EECIV for 1986-1992 Port EFi X flows, Ford Australia just copied the USA protocols. If knock occurs, the base 3 volt signal is pulled low.
"Do if true" ignition timing reduction if knock is present. How it does it is just switch related.
"Cut me a switch, bouy"
