crankshaft sensor replacement ????

[Dazajj]

yo yo yo what up peeps!?
i have a E36 318i 97, i'm trying to find ways to make this baby run smoother. I read in a post how this one guy who has the same car, replaced the crankshaft sensor and his car ran a lot smoother/better. anyways, i cant seem to find any DIY on crankshafts.. is that even the technical word!? i suck at cars, i just have a few tools and im trying to get some extra man cards by working on my car.. anyways, any help would be great! oh, so yeah, my goal is to make my car run smoother and quicker off of first... but yeah i know, i have a 318i so there's only so much i can do... thanks!

[hpmaxim]

Either the crankshaft sensor is working or its not. Maybe it can fail intermittently. But, its really not something that "ages" like some other sensors do. I wouldn't replace it unless you have some reason to believe its bad -- and that doesn't include you reading somewhere on the Interwebs that some dude changed his and the car ran smoother.

[jason325is]

^ +1, if it's bad, it's bad and you'll have major issues clearly necessitating a new one. It's not something that "half works" or "wears down". If it was bad, you would know something really wrong is going on, not just that you feel it should be smoother.

Also, your OBD would be letting you know it's bad right away.

[Dazajj]

Cool. Thanks for the help guys!!! Really appreciate it.

[slocar]

Maybe you're thinking camshaft position sensor?

As far as the replacement for it, the sensor itself is right on the front of the engine ... one bolt and it's out, but you might have to take the upper part of the intake manifold off to get to the connector.

[Dazajj]

does the camshaft help your car run smoother/faster/stronger?

[slocar]

My dads 98 318 was throwing a code for the CPS and upon replacement, it did smooth out the idle a little ... didnt really notice too much improvement in the way it ran in other parts of the rev range.

[hpmaxim]

The camshaft is what opens and closes the valves on the engine. No camshaft, no running engine. The sensor detects the position of the camshaft, but generally speaking it should be mostly known because of the crankshaft position sensor. The camshaft spins at exactly half the speed of the crankshaft, and should be perfectly synchronized with it. Because it spins at half the speed, there is exactly 0/180 degree ambiguity in it if you know where the crank is but not the camshaft. The camshaft sensor resolves this ambiguity.

Knowing the cam position, depending on the car can be either critical, or completely unimportant. Cam position enables the following three things: 1) sequential fuel injection (the ability to open the fuel injections individually such that they will close just as the intake valve opens), 2) adaptive knock control (the ability to know which cylinder is pinging/detonating if pinging/detonation occurs), and 3) the ability to fire individual ignition coils (if your ignition system does this, the cam position becomes critical, if not, it has no impact).

However, sequential injection, while better is not a huge improvement, and the car will run fine without it.

Adaptive knock control, while better, is not a huge improvement over regular knock control. If you have a 4 cylinder car, then its pretty obvious that every 4th ignition event is the same cylinder. The fact that you don't know which cylinder that is only affects your ability to save this data for later use, but doesn't have any real impact on the actual knock control while driving

The ignition coil situation is more critical at first blush, but the ECU may have the ability to fire two ignition coils simultaneously (sort of like converting to wasted spark) if there is ambiguity of not having a good cam position sensor. If the car has a distributor or wasted spark, its not even an issue. The 6 cylinder cars have coil-on-plug ignition, with one coil per plug, but I don't know what the 4 cylinder has -- and I don't know if they have the capability to go into wasted spark mode if needed.

[Dazajj]

Wow. Thanks for the detailed explination HP!