kerpz/ArduinoHondaOBD

Wrong RPM

silenec opened this issue · 2 comments

silenec commented

Hi, first of all - great work!
I got it mostly working but in Torque, RPM is always (both with OBD1 and OBD2 selected) exactly 7224 rpm with the engine off and ~300 at idle. When I raise the rpm to ~3000, it shows even lower value (~170).
What can I try to make it work correctly? Honda_PCScanner.exe shows correct RPM.
Car is a d15z6 EK3 Civic with 37820-P2Y-G11 ECU (OBD2b I think).

silenec commented

This is what I get with engine off: https://i.imgur.com/GlQqP3l.png
A=112
B=224
(256A+B)/4 -> (256*112+224)/4 = 7224

What should the A and B values normally be at 0 rpm?

silenec commented

Alright I think I got it.

hobd_uni2 uses:
OBD1 (1875000 / (A * 256 + B + 1) ) * 4
OBD2 (A * 256 + B)

And this is what works for me in Torque v1.8.205:
(1875000 / (A * 256 + B + 1) )

I use it as a PID override for RPM and although the RPM is not 0 with engine stopped, it seems to be correct with engine running.