The oil pressure sensor was leftover as unfinished business after I picked up the car from Marcus back in June. The factory Mazda oil pressure sensor was removed and we thought we could plug in the OEM GM sensor instead, but the ECU’s harness lacked such a connection. The next alternative was to run an AiM sensor instead. This is all in preparation of the dash’s install and the AiM sensor will natively plug directly into it.
Previously, Marcus had to remove the upper intake manifold in order to remove the Mazda oil pressure sensor, because it was made from dinosaur technology and ungainly in size. He installed and plugged an NPT adapter – this is where I could pick up from.
While this setup made it easier for me to proceed, I still dreaded the task. One look at its location and it was immediately evident that a challenge with limited space would lie ahead. The oil pressure sensor installs at the top of the block directly behind the UIM, near the firewall. I could have easily fit a socket in that location with a combination of extensions and wobbly joints, but the AiM sensor had a wire extending from its center…
This meant tools of open ended nature were required. Welcome to the world of cars, screwing on what is essentially a bolt is never as easy in actuality as it is on paper. Firstly, I had to stop what I was doing and make a trip to a local parts store to pick up a 7/8″ wrench to fit the body of the sensor, which I did not have. 7/8″ is a rather large size, which equates to a large wrench. As I would soon find out, there was absolutely no room for me to swing the wrench in that area without being stopped by the firewall or the UIM. Even after removing the rear crankcase ventilation line and the brake booster line to free up space.
I ended up having to chop down the newly purchased wrench. And then chop it down even more.
Using just the box end and relying on finger strength instead of leverage, I was finally able to get enough room to make turns and tighten the sensor down.
I ran the wire along the firewall and into the harness loom to pass through the cabin. Although the sensor couldn’t be replaced by Marcus during the last visit, I did get him to change out the temperature sensor on the oil pan with an AiM unit for the same purpose. These 2 wires will plug into the MXG dash and have their own independent channels, taking the readings directly from the respective sensors.
In order to guarantee the best possible execution and outcome during the MXG’s install, I’ve had plenty of time to deliberate on the planning. The box below contains an amalgam of supplies I’ve amassed to aid the venture, from a restock of my favorite Ty-Rap zipties to liquid electrical tape.
Here is the current look of the garage… the RX-7 continues to sit and the dust piles on. I have updates on the M3 to catch up on, but the motivation isn’t really there since it isn’t nearly as interesting as what I’m doing with the RX-7.