crxnatic

im trying to make the wiring for my vtec b16a on a crx obdo pr3 ecu.

im confused on my engine i see the solenoid is a one wire and then there is a light green plug with two wires is that the knock sensor ? and the same time i see a hole behind my engine where i see that people have the knock sensor there , my motor doesnt have the sensor there . there is just a hole there with a thread. so do i live that like that and just use the solenoid one wire and the other two wire ? if thats the case then i did it like that .
p

please let me know

crx_si-r

is your ecu chipped or stock? if its chipped you can buy the chip with the knock sensor eliminated. if your ecu is stock then i would get a knock sensor and install it. which harness are you using? i haven't seen any stock usdm 88-91 civic/crx harnesses that come with a factory knock sensor wiring, mainly because a usdm ED civic/crx doesn't have a knock sensor.

crxnatic

is the oil pressure switch the same thing as a knock sensor?

crx_si-r

no. the oil pressure switch is a single post sensor, where the knock sensor looks just like your Intake Air Temp Sensor but only has 1 terminal instead of 2. which harness are you using?

crxnatic

im using a si harness so im adding the vtec and the 2nd 02 sensor, but my motor didnt come with a knock sensor so im asssuming that pr3 does not need a knock sensor.

si harness dont come with a oil pressure switch connector. so im confussed

crxnatic

how do i add a picture to show you?
?

crx_si-r

si harnesses do have an oil pressure sensor. they are normally covered up by a rubber boot. its located right next to the oil filter. you will have 2 sensors by the oil filter. the sensor with a single post is the oil pressure, and the sensor with 2 posts is the fan switch.

in the pic you see the oil pressure switch and the block off plug with a indentation in the middle, that should be your fan switch on older motors. you can see the knock sensor as well.

crx_si-r

if you want to do the wiring for the knock sensor like factory then you will need to make sure you use shielded wire instead of regular wire. this helps cut down on static interference and giving off a false code. i always use shielded wiring just like factory on my harnesses. same goes for the o2 sensor wiring, honda used shielded wires for a reason.

crxnatic

ok now i understrand the vtec wiring picture. so the knock sensor is a one wire or a two wire? the vtec oil pressure is a two wire so im assuming one is for ground so where do i put that ground where do i plug it in? i think the knock is a two wire sensor so it has a ground also where do i put that ground on?

crx_si-r

The knock señor itself looks just like the green vtec pressure sensor but only has 1 wire

crxnatic

ok got it. what about the vtec pressure sensor it has two wire whats the second wire for? ground?

OneBadTurboCRV

Ground...