I am in the early stage of a 5.0 miata swap. I have a 91 Mustang engine/ trans and a 96 Miata. I want to send my harness to Jason but am not sure if I have the right harness? I only have one relay out by the mass air flow, Martins book shows two, a fuel pump relay and a WOT relay ( I have AC). The one relay that I have doesn’t match up to either of the color codes for those relays that Martin shows. I got the harness from a yard and they say it is of a 91? Also my computer is a A9P . Do I need to return the harness and computer for a A9L and a harness that has the two relays or will this work. I want this to be a easy swap and everything work right the first time.

Thanks!
Rusty

 

I'm digging this up from the dead....

I am also having the same problem. What is the solution?
My harness and eec are an A9P out of a 1990 fox body.

Thanks,
Chris

 

A9P is for a Mass Air car, however, it is for an automatic equipped car.


A9L would be the computer of choice.


Bill S.

 

I can work with any 5.0 Mustang harness. The fuel pump relay is not part of the main harness, its actually located in another harness under the Mustang's driver's seat. I add the entire circuit and relay into the donor main harness as part of my standard service.

A normal donor harness should have a AC WOT shut-off relay by the mass air meter and a main power relay by the ECU. When I convert them I relocate the AC relay to the same location as the ECU relay and add the fuel injection relay in that same location as well. Keep in mind that the person who pulled the harness or sold it to you may have removed the relays before selling it to you. Its easy to mistake the relay base for a plug if you are not sure what you are looking at.

BTW, now is my "slow time" which makes it an excellent time to get a harness to me for clean up and modification. I can turn most jobs around in under 3 weeks at this point.

-Jason