8th Generation Honda Civic Forum - View Single Post - Help finding VSS and fuel injector leads in 2008 LX?

KJSatz · 08-15-2008, 12:17 AM

Well they were designing that MPGuino to not require OBD-II, but I don't care about that because I have that--my only roadblock to getting a ScanGaugeII is the triple-digit price, to be honest.

You know I have been thinking about this for a while now, and I bet there is a way to make a sort of ScanGauge "lite" using a simple microcontroller setup or maybe something based on arduino to just get instantaneous and trip MPG. VSS is easy to get via OBD-II (it's just Mode $01 PID 0D, given in straight km/h). But there is no spec in OBD-II for fuel usage!

Does anyone know what parameters are used by the ECU to determine how much fuel to inject (these parameters such as engine load, engine rpm, throttle position, etc. are retrievable via OBD-II), in what way? If we could figure out some factor of current fuel economy, it would be easy enough to calibrate (as is needed in ScanGaugeII and MPGuino alike).

You directed me to forced induction for the injector lead question...is there a better place for this? It isn't exactly mechanical....

08-15-2008, 12:17 AM	#5 (permalink)
KJSatz Senior Member Join Date: Aug 2008 Posts: 164	Well they were designing that MPGuino to not require OBD-II, but I don't care about that because I have that--my only roadblock to getting a ScanGaugeII is the triple-digit price, to be honest. You know I have been thinking about this for a while now, and I bet there is a way to make a sort of ScanGauge "lite" using a simple microcontroller setup or maybe something based on arduino to just get instantaneous and trip MPG. VSS is easy to get via OBD-II (it's just Mode $01 PID 0D, given in straight km/h). But there is no spec in OBD-II for fuel usage! Does anyone know what parameters are used by the ECU to determine how much fuel to inject (these parameters such as engine load, engine rpm, throttle position, etc. are retrievable via OBD-II), in what way? If we could figure out some factor of current fuel economy, it would be easy enough to calibrate (as is needed in ScanGaugeII and MPGuino alike). You directed me to forced induction for the injector lead question...is there a better place for this? It isn't exactly mechanical....