Brief backstory, bought the swap few years ago and now I finally have somewhere/time to work on it. Trying to learn as I go

B20B block with B16 head, bought this amazon tuck harness but it does not have a vtec pressure plug. I noticed even the rywire harness does not have it but offers a delete bolt. Do I not need this plug?

 

Also the harness has a knock sensor plug but does not fit the plug on back of block

 

As you already pointed out, even the Rywire harness omits the VTEC pressure sensor plug. Both that sensor, and the knock sensor are not mandatory for getting the car to run properly. I own a Rywire harness and actually wasn't expecting it to lack the VTEC pressure sensor plug, but as you say it isn't included.

In the case of the pressure plug, I really wish the had included it. Even though it isn't required to get the engine running correctly, I see it as a small but good extra layer of protection. If your car isn't making adequate oil pressure and for whatever reason you don't notice it beforehand, having the pressure plug prevent you from going into VTEC could potentially help stop larger damage from occuring.

The knock sensor on the other hand is almost always useless on "built" or modified engines, and I think for the knock sensor to work correctly it needs to be on a matching engine + ECU combo. I believe good tuners will use other methods of detecting knock, at least while on the dyno.

 

Appreciate the helpful response. Seems to be a fairly common question but I feel like I've been reading so much stuff lately think I may have just started to over complicated the information

 

Am i replacing the extra gray plug now that ive changed the engine harness? Tried to start the car but got no crank and the oil light comes on

 

The extra grey ECU plug (part of the chassis/dash harness) MUST be plugged into the ECU (or an ECU adapter harness). So, what you have pictured will not work.