Alright guys so I've done a bit of research and can't seem to find my exact application. So I picked up this 90 DX off this kid, it has a d15b7 block with a mini me swapped z6 head. The motor is leaking oil like a sieve and the valves are chattering like crazy. The engine harness is all mangled, vtec solenoids not even plugged in (connection is melted) and random sensors are just not plugged in.
I have the opportunity to buy a FULL y8 swap my friend has for 250. Problem lies with in, I have no idea what OBD I'm using. I know the y8 is OBD2. So am I just collecting an EK EX OBD2 harness and a OBD2 ecu? Or is it a better setup to run the OBD2 then use the jumper down to an OBD1 ecu?

As it stands with whatever the kid before me did:
the dizzy which i believe to be z6 has a bunch of wires cut and butt-end connectors used to reconnect them back to the connector that goes into the harness. The ECU is a p28 ecu but there is a jumper harness that connects it to the engine harness. Basically have no clue from there. Obviously the car is already converted to multipoint cause of the z6 head.

Need to know what engine harness/ecu/if i need a jumper harness or not. Sorry if this has already been posted but I couldn't find something truly similar to my situation, if so please redirect me. THANKS

 

You use the original engine harness that came with the car and convert it to accept whatever engine and ECU you choose to run.
The jumper harness is what allows you to connect up to the different ECU and routes all the wires from your stock harnesses to the right pins on the new ECU.

It sounds like your engine harness is either in really bad condition or maybe just at the distributor. Possibly they didn't have the correct OBD1 style plug so they just cut the wires and hooked up directly.

If you aren't comfortable with the condition of the engine harness, then get one from the exact same model (Civic, sedan, CRx.. you didn't specify what you have), DX trim and from a 90/91 chassis.
You will then need to do the modifications to bring it up to MPFI (don't forget tot flip the TPS wires) and do what ever simple modifications are required for the OBD electronics on your engine. You will need to swap out the distributor plug, injector clips, and extend the IAT and ECT wires for the Y8 - probably a few more that I forgot.

The Y8 will run on whatever OBD electronics you want to hook up on it. Since you are getting the FULL swap, then OBD2 looks like a great choice. Do expect ECU codes since you don't have a pressure sensor in the gas tank.
OBD1 is the popular choice because of the tuning capability and ease of conversion. You can get a chipped P28 and run a tune that matches the Y8 fairly well and have a strong running motor.

 

I figured I had to use another obd0 harness in order to connect back into the obd0 body harness. I was just hopeful I guess, thinking I could get out of the deal of splicing wires. As far as my harness goes, yes, it is quite torn up, I'd like to get one in better condition. Then I guess I will figure out whats up with my jumper harness or get a new one thats not hacked up then use my p28 ecu.

 

I'm thinking about getting a Monotech obd0 dpfi converted to mpfi harness and the rywire vtec subharness, alternator adaptor, dizzy adaptor to avoid cutting wires as much as I can. Monotech stuff any good? Or nah?

 

True, engine codes if you scan the ECU, but no CEL or limp mode.

Go OBD0 or OBD1. I converted a CRX to OBD2 to run a D16Y5, ran into the aforementioned problem with the charcoal canister/gas tank lacking the pressure sensor. No big deal, but the overall process I went through converting the dash harness to OBD2 was difficult and I know for a fact that the info isn't out there because I searched and searched. Someday I'll type up my notes...

There are tons of OBD0 to OBD1 conversion harnesses but good luck finding OBD0 to OBD2.

 

Alright so convert an OBD0 harness with the OBD1 connections I need. Then use obd1 alternator and dizzy? If so, I figure bolting an obd1 alt to y8 should be no prob but is there a certain obd1 vtec dizzy that will fit the y8? If not I guess I can use the obd2 one and jump it to a spliced obd1 dizzy connection on my modded obd0 one.

 

Just use the alternator and distributor from the Y8. They are compatible with the OBD1 electronics.
OBD1 vtec dizzy is the D16Z6 and has a different bolt pattern and won't bolt up to the Y8 head.

If you are going to get a dizzy jumper, they can be purchased to go from OBD2 whatever you need it to do.

 

Went the GSR route...

 

You prob want to look at a budget OBD0-1 engine harness like from rywire or similar.