86 FC motor to 88 FC
 

Hello, i have an 86 FC with a 13b N/A. and i also have a 88 FC that HAD a 13b N/A. the motor in the 88 was blown, was removed and sold. my question is, can i just drop the motor from the 86 into the 88 without changing anything?

You'll need to use the 86's Emission Harness because the injector connectors are slightly different. Also, the 88 used high impedance injectors, while 86/87 had low impedance and a resistor pack so the ECU sees the proper impedance.

The other thing is that sometime during the S4's production, Mazda changed the rear iron coolant temperature gauge sender from a M8x0.75 thread to 1/8" NPT. Connector is the same (bullet connector), but the metric one needs a crush washer to seal properly. Easy way to tell is to get a 1/8" NPT pipe plug and try threading it in. If it's too big, your iron uses a M8 sender. These senders only need about 10 ft.lbs of torque

S5 and later use 1/8" NPT threads too, but with a 1/4" Quick Disconnect tab connector.

Everything else is drops right in.

okay, thank you, sounds simple enough. now gotta find the engine lift. lol

the easier fix would be to just buy a set of '88 n/a injectors, since that would make everything virtually plug n play but i guess it really just comes down to which harnesses you still have in the car. if none just take the engine out with the harness to the ECU and transfer the whole thing over. either route should be cake, i just like to keep things proper if possible.

I actually did just the opposite, 88 motor into an 86. Pulled the harness out with each motor; like they said, plug and play. I'm using the 88 ecu