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12aymond

1 vs 2 wire knock sensor install

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I am using a G4+ on a 1990 nissan 300zx with a vg30dett.

I purchase a Link brand knock sensor to use rather then the factory one.

My factory knock sensors harness plugs right into the link knock sensor so I am trying to see if it can be used this way without any wiring changes. Here is my issue/ concern though. The factory knock sensor is a "2 wire" sensor. however the harness is only pinned with one wire. The other pin is blank. The harness has two wires in it but the other wire looks like it is used for shielding. Can the link knock sensor function this way or will I need to run a ground wire to it or possibly all new wiring all together.

 

Pictures of knock sensors next to each other and factory harness for reference.

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20171122_175551.jpg

20171122_175603.jpg

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20171122_175646.jpg

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Im pretty sure originally the screen had a terminal on it and was used as the signal ground also.  I wonder if yours has been modified?  Some of the similar Bosch sensors could ground through the bolt boss but I dont think the Nissan sensors had continuity to the bolt hole.

I would crimp a new terminal on the screen and give it a try, it should be fine.

 

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It doesnt look modified to me but it does seem odd. I would be willing to just give it a try except that I can only access the knock sensor with the motor out of the car or pulling off all of the intake manifold/ timing. So I want to be 100% sure.

I just did a bit of digging to make sure my harness wasnt modified or damaged and it does appear that it is not. They are all this way with only one terminal in the plug.

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Wiring diagram indicates signal, and also shield on both sides (knock sub harness and also ECU side). ECU side shield is terminated at PIN 50 on a factory ECU. Ground not connected to sensor.

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Sheild and one wire should connect together somewhere near the ECU then connect to Pin 50.  The other wire goes to pin 23.  Polarity at the sensor connector is not important.

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On 06/03/2017 at 4:44 PM, MagicMike said:

 

Doesn't look like they are connected, but wiring isn't my strong point (actually not sure I really have any strong points!)

Edited by MagicMike
trying to free up attachment space as I have reached my limit

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As fare I remember the old Nissan knock Sensors make groudn through the block and one pin makes contact with the mounting surface. You can Check that with a ohm meter. 

Bosch knock sensor doesn't have contact between pin and mounting surface. 

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