This idea started with me thinking of adding an oil pressure sensor to my current system. There are plenty of pressure transducers out there that have a linear response and would be very easy to add on to my system like the one below:

https://www.amazon.com/Pressure-Tran...r+fuel+100+psi

This got me thinking, my car already has a factory oil pressure sensor/ switch and it would be really nice if I could just take the data coming off of that sensor and convert that data to a 0-5V output that I can input into the MPSciLink and data log that as well. So I dug into the factory system and the sensor looks to be resistance based. I went out to Rock-Auto and found a part number of 1S6621, which has an alternate part number of PS204, manufactured by Wells. I went to their site and found the data sheets and here is their data for the PS204:
PS204 (View Image)1/8-27 NPTF Dryseal
  • Switch closes 6-10 PSI
  • 90 PSI - 35-40 Ohms
  • 40 PSI - 40-50 Ohms
  • 10 PSI - 45-55 or Open
  • 0-3 PSI - Open


Looking at the wiring diagram, there are 2 wires going to the sensor, the GRY/YEL looks to be for the sensor and that goes to the gauge and BCM. There is a second wire that is GRY and that seems to only be for a pressure switch.

First question is, how accurate are these sensors? Should I just add another Tee Fitting to the line coming out of the block before the turbo feed and run two sensors?
Just starting my initial research.