DIY: Adding new Parameters (sensors) to OBD2 for logging.

[Harlan]

I put this together originally for my modded Rx8, but I figure other people will find this helpful.

Here is the thread on Rx8club which has the code:
DIY: Adding new Parameters (sensors) to OBD2 for logging. - RX8Club.com

And here is a video I put together explaining how it's done and showing it in action:

https://www.youtube.com/watch?v=qYqtvH7TyDQ

[Harlan]

Let me explain it a little better. With this you can add any 0-5volt sensor (for example measuring underhood temperature) to the CAN Bus so it can be read with standard OBD2 commands just like the stock sensors. You can even do 0-12v sensors or other kinds of sensors with the right coding/hardware.

[thingstodo]

I will give it a try.

My mileage seems to vary:
- temperature - a *LOT* - expected
- humidity? - a *LOT* - not so expected.
- cross wind - not quite so much as a head wind .. but still more than I expected

Anyone know of a weather station I can mount to the hood of my SUV? I'd like to log all of this and see if I'm imagining things ...

[Harlan]

I would use this one. https://www.adafruit.com/products/38...dnQaAm5k8P8HAQ
There is a lot of support available for it so writing a sketch to put the parameters on OBD2 shouldn't be hard.

Also the most likely reason you are having variance in FE with humidity is the effect on detonation the water in the air has. Your engine can advance more timing with humid air compared to dry air. There used to be a trick involving a bubbler and a mason jar with water that was popular for preventing detonation, but I've never tried it myself.