Bosch Knock sensor wiring

[mr2andy]

Hi all,
Can anyone give me some idea on how to wire a 2-wire bosch knock sensor to the M130?

Cheers
Andy

[Stephen Dean]

Hi Andy,

To set it up as a Differential Knock input, you connect one of the pins to B7 and the other to B13, this allows for the knock signal to float and helps to provide for a smoother signal that is not as susceptible to external noise. the other alternative is to wire one of the pins to B7, and the other pin to one of the ECU 0V pins, this can effect the signal if another sensor that shares the same 0V adds noise to the pin.

We also recommend that shielded wire is used for a knock signal where possible, or using twisted wires as a minimum.

[mr2andy]

Stephen,
Thanks for the information. Does it matter which pin goes to the B7 and which goes to the B13? and you mentioned shielded wires, should both of the wires within the same shielded cable or it is prefer to use 2 independent shielded wires for each pin. I assume the shielding should be twisted together and just goes into either B15 or B16 (0v) as ground?

Cheers
Andy

[Stephen Dean]

Hi Andy,

In my experience, there is not a difference as to the way that the pins are wired for the two pin sensors, the three pin sensors have a shield pin as well, that needs to be connected to a 0V pin on the ECU.

The shielded cable has two as a minimum wires twisted together in a common sheath, and the shield is connected to a 0V pin on the ECU end only.

[mr2andy]

Thank you Stephen...

[greenamex2]

And thanks from me. Would have been asking the same question in a couple of months time.

[ajwithers]

Hi Andy,

To set it up as a Differential Knock input, you connect one of the pins to B7 and the other to B13, this allows for the knock signal to float and helps to provide for a smoother signal that is not as susceptible to external noise. the other alternative is to wire one of the pins to B7, and the other pin to one of the ECU 0V pins, this can effect the signal if another sensor that shares the same 0V adds noise to the pin.

We also recommend that shielded wire is used for a knock signal where possible, or using twisted wires as a minimum.

Applying the setup above to an M150 using two Bosch knock sensors would you wire one sensor to A13 and A14, and the other sensor to D07 and D13?

Thanks in advance,
Aaron

[Stephen Dean]

Hi Aaron,

That is correct, D7 and D13 would be allocated as Differential Knock 1 and A13 and A14 would be Differential Knock 2.

[jallenmd]

Continuing this line of inquiry, how would two Bosch sensors be wired to an M170 with just two knock inputs?

Thanks,
Julian

[Stephen Dean]

Hi Julian,

To wire the two sensors in, you use a Knock Input to one pin, and a Sensor 0v to the other pin on the sensor.