I finally got back to my Spec Miata project after a couple of weeks of inactivity due to work and travel. Today’s primary task was to replace the stock oil pressure sender. The primary reason to install an aftermarket gauge in the Miata is that my 1999 stock gauge doesn’t indicate true pressure. Instead, it simple indicates if there is or is not oil pressure.

Getting the stock pressure sensor out of the engine block is a little bit of a pain due to the inaccessibility. But using a 24mm deep socket and some patience is rewarded. The stock pressure sensor can only be seen with the engine removed or from underneath the car looking. However, removal of the sensor is best accomplished from the top of the engine compartment reaching under the engine block.

The following picture shows the location of the sensor above and to the left of the oil filter.

Replacing the stock sender with a remote sender

For my needs, I installed  a remote oil pressure sender relocation kit from Advanced Autosports. Using this kit, you can reconnect the stock sender and also add the aftermarket gauge connection to the new port. It is important to use high-temperature thread sealant on the fitting that goes into the engine block. You can pick this up at most auto parts stores.

Multi-port with stock sensor and aftermarket gauge tubing

For my application, I chose an AutoMeter 4421 2 5/8″ mechanical gauge. I mounted it in my radio plate next to my water temperature gauge. Note that you will also need to do some wiring into the fuse panel for gauge lighting (if desired).

Oil pressure gauge (on the right) with water temperature gauge

If you are reasonably proficient, then this job only takes a couple of hours.