Thread: Someone school me on the crank position sensor & lightweight flywheels

I have a b14 with a u12 det, it has a lightweight flywheel with an extra tooth or a missing tooth, I can't remember. Anyway, it causes an intermittent CEL, but everything I have read says that it doesn't matter. My dad is convinced that it has something to do with the bad idle on the car. I tell him I don't think it does, but I can't tell him why. Can someone clarify why this particular sensor doesn't affect the operation of the engine? I think the b13 didnt have this sensor, but I'm not 100%. Thanks.

IIRC - the b14 crank sensor "counts" the teeth as they go by and if it reads an incorrect number it just throws off the sensor that little bit which triggers the light

if I am incorrect someone jump in!

Obd2 crank sensor is strictly for emissions purposes. When I say emissions, I mean ensuring the smog readings are correct. It works inconjunction with the o2 sensors to determine which cylinder is not burning right and will throw a code. It does not interact with the timing of the injectors or the ignition.

Idle issues are always a problem with these cars. There are quite a few systems involved that keep the idle in the proper range. Be sure to check and set the TPS, clean and reset the IACV, make sure base timing is set to 15 degrees, throw in some new spark plugs for safe measure.

You can see here on page 242 shows the emissions and engine control sensors. If you look at crank sensor you will see it has a tiny "1" next to it. At the bottom of the page it tells you what that means. "These sensors are not directly used to control the engine system" http://www.nicoclub.com/FSM/Sentra/1996/EC.pdf

Page 243 even shows the sensors used to determine injector output.

Awesome. Thanks for the replies. I'll do some more reading.