Let's start with the easy one. Torque setting for the knock sensors is 20Nm. I found in the following PDF, page 165:
Service Manual 8-cylinder engine (3.7 ltr & 4.2 ltr 5-valve AQF, AQG, ARU, AUW, AVN, AVP, AKC, .pdf
As for the cable route, here's a couple of photos from the following thread, from when I had a massive coolant loss, and then did as much work on the engine as I could:
https://forum.a8parts.co.uk/showthre...t=16865&page=6
This is the route of the original cable:
This is the route of the new cable. From memory, what I did was feed the cable from the 3-pin end underneath the coolant pipe, and then along the top to the front of the engine:
This photo shows the cable hanging down over the front after the manifold was put back on, and the next one is a zoomed in version, with the knock sensor marked in red. If you follow it up, you'll see the small gap that the cable sits in:
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2001 A8 D2 FL 3.7 Q - LPG Conversion, Engine: AKC, Gearbox:FBB, Colour:LY5X Aqua Blue pearl effect, Interior:WJ light beige/dark beige valcona leather with burr walnut inserts
My DIY jobs -
Replaced alarm horn,
Replaced Coolant Temp sensor,
Updated RNS-D firmware,
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Dashcam Installation,
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2008 S8 D3 5.2 V10 - Engine: BSM, Gearbox:KLW, Colour:LY7F Suzuka Grey Pearl Effect, Interior:Black/Black with Silver/Black valcona leather with carbon atlas inserts, Bang & Olufsen, Heated windscreen, Soft-close doors, TV, DAB, AMI, Quad Zone, Auto Boot, Auto dim Mirrors, Keyless entry, PDC with rearview camera, AFS II Headlights
My DIY jobs -
Fan Jet Windscreen Washers,
Retrofitted Electric Side Blinds