Post by
KALMUSI »
https://forums.nicoclub.com/kalmusi-u79683.html
Thu Nov 29, 2007 9:12 pm
The sensors are on the front of engine, and are identical units, but mounted at different angles. I too thought they were different when I first looked at them.
You need to remove the plastic shroud on the top of the engine in order to see the left (driver) side unit. It is mounted in a hole in the top front of the cylinder head, and picks up the position by magnetic pulses from the camshaft gear, which is in the front of the engine, and driven by the cam chain. I had to loosen the engine ground wires to get my socket wrench on the mounting bolt. The shop manual recommends cleaning the grounds, so I wire brushed them before putting them back together.
The sensors fit tight in the cylinder head, due to an o-ring gasket, so I had to jiggle and pry them out - carefully, as I didn't want to break anything, and have it fall into the engine.
The right (passenger side) is mounted in the side of the cylinder head, and it's a bit tricky to get a socket wrench on the bolt, but I did it with no skinned knuckles.
I spent about an hour to swap both parts and clean the ground terminals, and didn't get my shirt dirty. Since I had never done it before, I think my time was about double what a "pro" should need. I think the dealer charges what they can get away with, based on perceived value - in other words, they rob from the rich, the poor, and everyone in-between. Plus, I bet they didn't clean the ground wires.
The hydraulic pressure is not opening and closing the valves directly - this is still done by the camshaft, which is driven by the crankshaft. The hydraulics shift the timing of the opening of the valve by changing the relationship of the cam lobe (the pointy egg shaped part that opens the valve) to the crankshaft position. I don't think we will see a time when the camshaft goes away, and the valves are electrically operated, because it takes way too much force - the pressure would need to be huge.
On another note, as soon as I fixed the camshaft sensor code, I started to get P0171 - Lean codes and it was hesitating over 4000 RPM. Bottom line - new MAF. It's a $400 wholesale - $590 retail part for the 2001 Pathy, BUT ... per other posts in this forum, I got the '01 Maxima sensor for $78 and $20 overnight shipping - $98. This part take 5 minutes to replace - I did it in the parking lot at work. Engine is now running great - and no codes - so far! This would have been $700 - $900 at the dealer - nasty!