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Wiring up a 3 Pin Knock Sensor with Screened Wire

EFI Wiring Fundamentals

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Hi all, currently in the process of making my first Race Spec harness, and boy do I have a lot to learn.

I am currently stuck on trying to figure out exactly how to wire up a 3 pin knock sensor that VW employ in the majority of their vehicles.

I am using an EcuMaster EMU Black.

The wire I'm using is Raychem 2 Core Shielded Wire (not even sure if it's the correct wire).

One pin on the knock sensor is Signal, next is Ground, last is Screen.

Signal goes to AVI, Ground goes to sensor ground, but screen, am I wrong in saying I need to solder sleeve both ends with termination cable, having one go to the Screen pin on the sensor and the other going to power ground?

I appreciate any input.


EDIT: I've attached a photo to show the construction of the knock sensor

I think you do it just like the picture referenced in this thread:


So the shield is only grounded at the ECU end of the wiring.

I am surprised you can use an AVI (analog voltage input, I assume) -- I would think you would need to use a dedicated knock inputs since normally there needs to be special signal processing on a knock signal).

Hi David!

Thank you so much for your reply.

I had meant the Knock Sensor Input* not AVI, just rolled off the fingertips!

Digging around more and speaking to better informed people, I understood that the pigtail on the end of the knock sensor is already shielded, and the shield continues through the plug on the third pin, so when using shielded wire, in this case you would terminate both sides of the shield, the end to ECU and the plug side to the pin purely because it's carrying the shield through the pin.

Would that be correct?