Auxiliary CAN BUS Module

[JimmyM]

So my 3rd Gen (2011) Expedition has an HS-CAN bus that I can use an OBD2-Bluetooth adapter to connect to. I use Torque Pro to display various engine parameters. Temperatures, speed, etc.
However, things like Oil Pressure, Oil temperature are not available to the ECM.
So what if I want to know my Oil pressure or oil temperature, or something else? I'll have to install individual gauges.
But I want to show all of those extra things in Torque Pro.
Our Expeditions have several HS-CAN modules. ECM, TCM, etc. I pull the transmission temperature by using a different OBD2 header to request information from that module. What if I added a new module to the HS-CAN bus? It can gather pressure/temperature data from where ever I want and then those values will be available by using that modules OBD header.

Right?

1/8" NPT pressure sensors are cheap and output 0-5V for pressure, temperature senders are cheap and use 1 wire. These signals are easily acquirable. A few sensors and I could monitor oil temperature and pressure. A remote filter could easily be monitored for differential pressure by calculating the in and out pressure difference. Etc.

I've ordered some parts and will start fiddling around when they arrive.

Thoughts?

 

[JimmyM]

I thought some might find this interesting. But I may have overestimated.
In any case, I just got back from my truck. The hardware and code works just fine.
I have filters in place to ignore all other CAN Bus traffic except that sent to the module's address. The new module sends data upon request (via Torque Pro). I can also send commands to perform actions on the hardware as well. It can monitor the status of an oil cooler fan, for example, and report it to Torque, and a button in Torque can override a thermostat operation and command it on.
I'll be ordering some temperature and pressure sensors next to get it hooked up. When installed, the new module will be mounted under the hood and connect to the HSCAN where I can find it.

 

[JimmyM]

I received my pressure and temperature sensors the other day. But neither temp sensor came with any temper/resistance data. All I got was a 3 point reference from 1 of the manufacturers. So had to do a calibration on them both. I used a small pot of vegetable oil, a digital thermometer, and my Fluke DMM. For each of them I got 45 points of data from 32F to 300F. I only got a few points from 100F to 32F because frankly I don't care if my oil temperature readings are off by a few degrees at room temperature. But a lot of points between 150F and 300F should make for a pretty good reading accuracy.

Now I just have to package it all up properly and wait for some warm weather.

 

[JimmyM]

It's installed and working nicely. When not in use, it only draws 5mA.
When very warm (oil temperature at 155F, not quite hot), the oil pressure sits at 28-30PSI at idle in gear.

 

[no MORE_MPG]

Hi Jimmy,
I just started reading on the forums to find confirmation of the Motorcraft oil filter part number and eventually found this lonely thread.
I am intrigued and impressed! I don't think that I have every heard of someone adding a new module to their vehicle's HS-CAN bus. I understand the theory, but it's a bit out of my league. I'm more ME then EE.
Did you make the module yourself?
I am running Torque Pro also, but don't really know much about it yet. I would like a transmission gear indicator (none seem to work) as well as oil temperature and pressure. I think that I'll likely just T in an oil pressure sender and get an aftermarket gauge. I suppose that Torque Pro may have the ability to send an alarm at set points for oil pressure. It sounds like this has the possibility to save an engine. Much more likely than happening to notice a gauge.

Just wanted to let you know that I appreciate your efforts to share!

If the module is not too hard to build; Arduino plus a a few wires run to the right places, then I'd be interested to know more. If it needs a custom board, I'll probably not end up actually doing it.

Though, I be you could make a product out of this. I am seriously disappointed to find out that the oil pressure gauge is just an idiot light in disguise! How much would it have cost to send a variable signal?!?

 

[JimmyM]

Thanks for chiming in. I thought that with all of the oil pressure/temp questions I've seen here and in other Ford forums, there would be more interest.

I know. An idiot light for oil pressure. But based on the huge variability in oil pressure during normal operation, I can see Ford's point. I was really more interested in oil temperature. I see people adding oil coolers, etc and wanted to know if it was even necessary. My oil temperatures rarely exceed 200F. I think I saw 230F once towing a my camper in the summer on a long uphill pull. But even that is a walk in the park for modern oils.

I love Torque Pro, I've used it for years. There is a Transmission Gear PID actually.

It's literally a voltage regulator, an arduino nano, and a cheap-o CAN-to-SPI adapter. That's it. If I were to make it into a proper product, I'd design my own integrated board. But for a one-off, the separate components mounted on a piece of perf board in a plastic box is fine.