Project Miata Update

Figure out why MS3 is not reading NB cam sensor. Could be bad sensor or bad wiring between sensor and CAS harness.

So I think I fixed the cam position sensor (CMP) issue: power and ground were apparently swapped by mistake due to misread wiring diagram (sensor pigtail has three black wires so no help there). I Googled pictures of exemplar 1999-2000 Miata engines and zoomed in on the CMP sensor to verify the OEM wire colors.


Apparently when reading wiring diagrams, the view is as though you’re looking at the back of the connector where the wires go in. I get that.


However, when looking at the actual diagrams of connectors at the bottom of the wiring diagram page

the view is as though you’re looking at the front of the connector like so. Keep in mind the connector is actually “upside-down” in this pic but you get the idea.

Here is my new harness. CMP and crank position (CKP) sensor harness repairs completed and wrapped with new split braided wiring loom and electrical tape.

I only ever use Scotch Super 33+ tape as there is no value in using inferior electrical tape. I have Raychem DR-25 heat shrink but I would have needed some Raychem SCL or heat shrink boots to achieve that professional motorsport wiring harness look. See for more info.

P.S. step down butt connectors are awesome for splitting the power and ground from the original CAS harness into two for the discrete CMP and CKP sensors.

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