Engine Swap – Part 2

This post is what it’s all about. This is what I did to make this swap run, including all the parts I ordered and where I got them from.




  • 1999 Fuel Rail (Treasure Coast Miata)
  • 1996 Fuel Pressure Regulator (from my old engine)
  • 2001 Purple Injectors (came with engine)


  • Reverant Megasquirt MS3 Basic (MS Labs)


  • NB Throttle Cable (eBay)

Connectors Required:

Now that you have all the parts – this is what to do.

The first thing I did was remove the butterflies on the 2001 intake manifold. This is extremely simple to do. Take the intake manifold off and carefully unscrew the butterflies from the supporting rail. I don’t even know how Mazda put these together without breaking half the screws in it. You’ll probably have to drill a few out as looking at the screws wrong will destroy the head. With the flaps removed, pull the rod out. Fill the holes with some JB Weld and sand down the high spots with a file.

Next, take the fuel rail off of the old engine and remove the FPR regulator. Bolt the FPR to the ’99 fuel rail and install it on the new engine. I’ve read that the newer injectors aren’t entirely ideal to use on the NA engines as the NB runs at a higher fuel pressure – but they will work. I couldn’t bring myself to install my NA injectors on the new engine as they were totally disgusting. So – choose the injectors you are going to use and put them and the fuel rail on the new engine.

I didn’t do this, but wish I had. Get some new fuel line (3/8″). I got 4 feet from Autozone, which ended up being plenty, 3 feet if you feel like risking it and saving a whopping 4 dollars. Cut the 4 feet in half and connect one half to the bottom of the FPR, and the other half to the top. Route them how you like. I put the line off the bottom of the FPR under the manifold behind the throttle body. I just put the top line over the intake. Run a vacuum line from the side outlet on the FRP to a vacuum port on the intake. You can do this after the intake manifold is on and the engine is in the car, but it’s kind of challenging to get the bottom fuel line on. I’m pretty sure it would be impossible to get the vacuum line on, but I did that before putting the intake on.

Take the main engine harness from the old engine with the few remaining sensors and hook it up to the new engine. One of the sensors is blocked by a tiny allen screw on the NB engine. Simply take it out and replace it with the sensor.

Make sure everything is connected as I can’t imagine taking the intake manifold off while the engine is in the car.

Now it’s time to rewire everything. I’ll lay this out by sensor, and base everything off of the color wires that were in my car.



Cam Angle Sensor:

Crank Angle Sensor:

With those wired, back to the fuel. Connect the fuel line that is coming off the bottom outlet of the FRP to the hardline closest to the firewall. Connect the line coming out of the top to the one closest to the radiator.

That pretty much covers everything I had to do to get this to run. I spent a little while figuring out the wiring, thinking I had something wired backwards. I’m pretty sure I had everything wired correctly the first time and it would have started right up, but I had the fuel lines reversed. Typical.

Hopefully this post helps someone! I don’t have any of the emissions equipment hooked up anymore, which is why I didn’t talk about any of it. I think most of it should be plug and play except for the EGR tube to the exhaust, which needs to be modified slightly to get it to line up.