quck tip for you 3.6 owners... knock sensors

[YeuEmMaiMai]

If you ever have to replace them, Subaru states to take the intake off....yeah, no.

 

here is how you do it

 

1. Disconnect battery

2. Remove Engine cover (if you still have it)

3. Remove Serpentine belt, marking what side faces front of car.

4. Remove idler pully under alternator (easier access to loosen the long bolt on bottom of alternator.

5. Remove positive alternator termial, control plug, A/C sensor pressure plug. and gray plug to right of A/C pump.

6. unclip harness from black channel that is part of the engine cover bracket

7. remove engine cover bracket

8. loosen lower alternator bolt

9. remove top left alternator bolt that you loosened to remove engine cover bracket

10. remove alternator

11. Remove barometric sensor on left side of intake

 

12. using a 10 or 12 mm (I forgot) socket, universal joint, and 9" extension, loosen passenger side knock sensor and then rotate it a bit so you can easily unplug it, t

 

14. on the driver side go in to the left of the A/C compressor and

use a long screw drover to press in the clip and then tap the screw driver so the connector moves back a bit so that the lock does not re-engage

 

15. Go in behind the A/C compressor and remove the knock sensor bolt completely then pull the sensor up and unplug it.

 

to install the driver side knock sensor

 

16. while holding connector with one hand use a set of needle nose plyers to insert the knock sensor into the connector until it clicks.

17. insert bolt into knock sensor

 

***this part is the pitb if you have large hands due to limited space***

 

18. get the nock sensor back over the hole and use your fingers to start the bolt.. you will know if you have it when you cannot lift up on said bolt

19. while holding the knock sensor in the correct position, tighten bolt

 

to install the passenger side sensor

 

19. put bolt into sensor

20. reach in and start the bolt

21. rotate sensor so you can plug connector in

22. while holding sensor in correct position, tighten bolt

 

the passenger side is much easier due to lack of hard lines under intake

23. reinstall barometric sensor

24. reinstall alternator

25. reinstall front idler pully

26. reinstall serpentine belt noting what side goes towards the front of the car.

27. reinstall alternator power lead, connector, a/c pressure switch, and gray connector and clip harness back to front cover

28. reconnect battery.

29. reinstall front engine cover

 

Start car and verify all is working as it should

Edited May 1, 2020 by YeuEmMaiMai

[dgoodhue]

How are you going to torque the knock sensor to spec? I am not positive about Subaru knock sensor, but many knock sensors calibration is affect by the torque.

[YeuEmMaiMai]

you can use a torque wrench

[dgoodhue]

you can use a torque wrench

 

Not with a swivel.

[YeuEmMaiMai]

Not with a swivel.

 

well unless you want to take an intake manifold off, that is your only other route... personally I just snugged them down and 1/4 turn more which was about what they were tightened to...I am aware that a swivel will affect torque based upon angle... but since the angle is small you can add 10% or so and be done with it

 

spec is 14ftl lbs so barely tight

 

 

the code has not returned, it typically showed up in the first 10-14 mins of driving so I think we are good to go here...