ECUs and Tuning Discuss Engine Management, Tuning, & Programming

3-wire knock sensor shielding

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Old 06-01-2015, 07:01 PM
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Default 3-wire knock sensor shielding

I am in the final stage of my turbo project and I am beginning the electrical work. I have a 3 wire Bosch knock sensor (0261231036) and 4-wire foil shielded cable (no drain wire unfortunately).

Pin 1 and 2 go to their respective singal/ground wires on the MS3. My question is where should Pin 3 (shield) go to? Should I solder Pin 3 to one of the four wires and ground it to the chassis? Does Pin 3 need to touch the foil? Any input is appreciated. Thanks.
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Old 08-21-2015, 10:06 AM
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Instead of creating an additinal thread, I'll post a similar query here.

Which pins can be used for shielded ground on ms3? Also OP, I don't think you'd want to ground the foil shield to the car chassis.

What other wires would be good to shield? I'm about to go back through my harness and replace my wideband wiring as the radio is making the signal jumpy as hell
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Old 08-21-2015, 11:00 AM
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If you don't need the shield to act as a conductor for the signal ground, ground the shield to the engine block or chassis, at one end only, at one point. Leave it floating at the other end.

If your shielded cable has only one center conductor and you need to use the shield to connect the ground of your sensor to the ECU, you ground the sensor end of the shield wire to the sensor ground, and ground the other end of the shield wire to the ECU signal ground wire. WARNING: this is only OK if the sensor ground isn't internally connected to the engine block like with a 1-wire piezo knock sensor.
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