I am trying to help a friend with a B16 install into the 91 CRX. My question is, what is the sensor that is right under the intake manifold in the back of the block? (Not the knock sensor) I ran the harness around, but cannot seem to find a wire that would connect to this sensor. Thanks for the help.

 

There should only be 2 sensors. The oil pressure switch (one wire) and the radiator fan switch (two wire). (Assuming its an OBD-0 engine - if not then it will just be the OPS.)

 

No. The motor is out of a 99 Civic SI supposedly. I didnt know there was an oil pressure switch in the back of the block. I will try to get a pic of it tomorrow to help better explain. I think its a one wire sensor, far as I can tell.

 

He is talking about the knock sensor

 

Who was talking about it? Me or him? He clearly states "not the knock sensor" in his first post... So I did not list that.

So OP, the only other sensor there will be is the knock sensor (one wire).

The knock sensor has a regular "Honda style" clip; it's also has a hex body for a socket. The OPS has a push on wire that is interference fit; this is circular with notches going all the way around.

 

he has to be talking about the knock sensor. that is the only sensor located right under the manifold.

the only other option would be the crank angle sensor that is found obd2 motors, wiring comes off the oil pump. that would be a 3 wire plug.

 

ok. i finally got a couple pics. As far as i can tell, its a 1 wire sensor.

 

Asi stated before, knock sensor

 

If that's the knock, what is the other sensor towards the bottom of the block? Its the one with the "pin" sticking out?

 

That would be your oil pressure switch

 

yup oil pressure switch is just that single nipple pocking out on the side of oil filter that one u took pic up is definitely the knock

 

Ohh. I had the 2 backwards. My bad. Thanks guys.