New owner and something looks wrong

[BOPOH]

Hi, i recently bought 96 240sx SE 5 speed.
CEL is on: P0135, P0325, P1445
Ordered new knock sensor.

Engine had rattle noise, so i opened valve cover and discovered top guide broken. Apparently it was broken for a while, check out damage to guide and valve cover.

Here is my biggest concerns:

1. Check marks on chain and sprocket, aren't they supposed to be aligned?
2. if top guide broke, does it mean chain is loose and i need to replace top(or both) tensioner?

http://i219.photobucket.com/albums/cc198/BOPOHkgb/20130926_111156_zps345eb5cf.jpg

http://i219.photobucket.com/albums/cc198/BOPOHkgb/20130926_111112_zpsdeb59eca.jpg

http://i219.photobucket.com/albums/cc198/BOPOHkgb/20130926_111008_zps9463a0d2.jpg

http://i219.photobucket.com/albums/cc198/BOPOHkgb/20130926_111148_zpsa4a66327.jpg

[cotbu]

Always put the engine at TDC, when shooting timing chain, and or cam pictures.
We can't tell if the mechanical timing is correct otherwise, nor can you. Since your not at tdc, No, installation marks on the chain won't line up like that.
The broken guide could be from improper installation, or it could be that the chain was loose. In your case i would examine the chain for wear, as in replacement as opposed to adding more tension right now.

Clear codes
Put engine at TDC
Examine chain
set timing to 20deg BTDC
let it idle afterwards and listen for anything abnormal
check codes again!
leave the top guide off!

[BOPOH]

Thanks,

I checked the chain and it looked ok. Also i just removed knock sensor, do you think it's bad? j/k i'm glad new one is on the way. Is this harness good? something looks wrong

http://i219.photobucket.com/albums/cc198/BOPOHkgb/20130930_125017_zps180cf66a.jpg

http://i219.photobucket.com/albums/cc198/BOPOHkgb/20130930_125003_zps0bd6314c.jpg

[cotbu]

Trim the excess shielded wire hanging by the white wire, tape and loom. I would also test continuity and call it done.
When you install the new sensor, don't over tighten it.