95 into a 96 electircal connector problem NEED HELP!!!
 

alright im going to try and give you guys all the information that i can in hopes that someone who knows the wiring of these cars or has access to the diagrams that can assist me in solving this issue.

the motor is from a 95 car and the car it is now in is a 96 car.

here is the plug that comes from the cars wiring harness. it is loomed with the plug for the CAS sensor and oxygen sensor plugs. it has 4 pins and 4 wires. it has the following wires coming from it:
BLACK
BLUE
BROWN
BROWN/WHITE
https://www.miataturbo.net/attachmen...ine=1331604529

and this is the plug that the above plug is supposed to plug into. this has 6 pins with only 5 wires going into it. these are the wires going into it:
BLACK
BLUE
BROWN
BROWN/WHITE
BLACK/WHITE
https://www.miataturbo.net/attachmen...ine=1331604529

now im trying to figure out what this black/white wire is that was on the 95 cars but not on the 96 cars. what does it go to? is it necessary? etc...

i do have a complete 95 wire harness in my garage to use if needed. please help me!

I'm not sure what the connector your looking at is for, but the 95 was an OBD I setup and the 96 was an OBD II. I'm kind of surprised that one small connector is the only problem you've had so far, I was under the impression the ECUs were wired up differently as well.

I am almost positive the black/white wire is for the tach signal. The 90-95.5 coils/ignitors were 4 wire and sent the tach signal back to the gauge cluster. In 95.5 and up they switched to 3 wire coils and the tach signal was handled by the ECU. If you use your 96 coils you should be fine.

Swap in the engine side of the harness from the 96 motor. As previously stated, B/W wire is for the tach signal and not used in the 96 car. Don't swap the entire harness in the car to the 95 one as that is way more of a pain in the ass than the 96 engine side harness.

I am missing why he is swapping harnesses at all. It should not be required to swap in a 95 engine. Just unplug all the harnesses from the old 96 engine and replug them into the new 95 engine.

I am saying the same thing you are right now, so I believe you are misinterpreting what I said. The motor harness from the 96 motor needs to be installed on the 95 motor. This harness is the one that is from the four ping plug to the coils.

Coil harness. You can either source '96 coils or cut that connector out, connect all the similar-colored wires, and leave the black/white wire disconnected. It's the tach output wire for the 94-95 coils.

Im going to assume you meant to say source a 96 coil harness as simply getting the 96 coils would not solve the problem. Not trying to be nit picky, just didn't want any confusion.