Adding Oil Pressure to factory canbus
 

Howdy,

I want to add a oil pressure sensor to my car and also data log it with my race capture unit. Since my race capture can read can bus data I wanted to see if its possible to wire in a oil pressure sensor straight to the factory can bus.

The AEM 30-0307 supports a canbus output for their AEM Infinity ECU, can I just splice the can high / low wires into a factory location and have my data logger sniff the network for the data? I've attached some documentation on the gauge.

I don't think my response here is going be helpful, but the OEM unit is a switch not a sensor. It's a normally close switch. If it's in line with all the other engines I've come across from Subaru (which it looks to be), it triggers when oil pressure drops below 2.1psi. Which is great for telling you your engine just blew up :/ If you can make this work, I recommend setting an alarm or light to go on at 14psi, which is the FSM minimum allowable oil pressure.

Yea I’m looking for more of a data logging solution so I can verify I’m not having oil starvation issues. I wasn’t going to use the factory dummy switch as that thing is kinda useless. I’ll be installing an actual oil pressure gauge, but I want the ability to datalog as well. Since I can read canbus information I figure I can add an extra node to the network and read the oil pressure gauge info off of the canbus (the aftermarket AEM data not the factory dummy switch). But I want to verify if anyone else has done something like this before I fuck with it.

I understand what you're wanting to do. I wasn't sure if the switch is process through the ECU the same way as a typical sender, or if the switch was just supporting the idiot light. The oil pressure light coming on doesn't trigger any response from the ECU. Whereas other sensor inputs, like coolant temp, affect tables that the ECU pulls from to keep things safe if temps get beyond (or below) an optimum temperature.

I think the issue you will run into is you will not be able to set-up the new sensor on the existing Subaru CAN network. You would have to be able to adjust the ECU to not only see the new Oil Pressure sensor on the CAN network, but then also output the data to the OBD port.

I can speak from experience that it is very difficult to get oil pressure and oil temp. into the RaceCapture through the CAN network. We struggled to get a RaceCapture Pro unit to see the sensors coming from a Megasquirt. Once we did get the RaceCapture to see the sensor data through CAN, we could not get the data to make sense, let alone be useable.

We have since abandoned the RaceCapture in favor of an Aim unit, which instantly handled both Oil Pressure and Oil Temp coming from the Megasquirt via CAN data. I am not saying the RaceCapture is a bad unit, we just could not get it to display the data we wanted via CAN, so we moved on to another until.

https://forum.autosportlabs.com/view...hp?f=40&t=6391

What actual hardware do you have?

Can you not use the sensor as an analog input into your Race Capture? Can you connect your Race Capture to multiple CAN?

On the other side of things, I have a K24 running on a Haltech Elite 1500 with CAN integration. The Haltech is plugged into the stock CAN network, but it also has a second CAN network that uses Haltech CAN IDs - it rebroadcasts pretty much everything relevant from the stock CAN onto the Haltech CAN (individual wheel speeds, steering angle, etc) and then I have my AIM wired into the Haltech CAN to log everything (oil pressure, oil temp, ait, throttle position, dbw position, engine limiting, etc etc).

Also, the CAN wires in the stock OBD plug or the accessory connector behind the radio work fine to tap into the vehicle CAN.

Was the difficult you had mapping the can data? I figure since AEM provides the message specs in the documentation I would be fine in that department.

I have a Race Capture MK2, so no analog input without either upgrading to a race capture pro, or buying their analog kit.(But i figure if i get the upgrade kit i might as well just get a race capture pro). My line of thinking is if I can broadcast the oil pressure message from the AEM oil pressure gauge onto the factory bus I can just program the race capture app to read the message via the spec i posted in the original post.

Also FYI this is just me planning for how to deal with data logging on my gen 2 GR86 that still hasnt shipped yet... The OBD2 plug would not work for my case as I believe most can bus messages are filtered on the plug. I'll be making my own little dongle to plug into to the noise generator ECU for can data.

I'd personally just try it. The AEM is the same network speed and my brief bit of logging hasn't shown anything already using the 307 ID.

correct, the GR86 has atleast 4 "networks" connected via a gateway. the OBD2 is standalone and will not spit out anything below canbus ID 0x7F0 i think. if you want to connect to the "body" network. you can use the ASC connector, theirs another network that connects to a "options" connector behind the radio, this one is connected to the gateway and also the telemetric unit. Then the powertrain network thats just safely critical data.