Fuel used goes up when engine is switched off

video: https://streamable.com/pcgci7
The app doesn’t seem to recognize when the car is coasting or when the engine is shut off, as the mpg goes down when coasting and when the engine is entirely switched off (see MPG and $ in top right area)
any ideas on how to get it to report this information correctly? Also, how can I accurately determine what value i need to put into the fuel correction factor in order for it to match the mpg shown on my car’s dash?

How are you connected to your vehicle? OBD2?

Yes, via a VEEPEAK OBD2 adapter over Bluetooth

Do you know if your vehicle has MAF sensor, MAP sensor or both?

I believe both. 2020 Volkswagen Jetta S, M/T 1.4T

Alright, I will investigate this.

With quick look, I could not find anything wrong. The fuel consumption is always set to 0 if there is no RPM signal.

That’s very interesting. another thing I noticed is that the instant MPG goes up and not down when costing with the clutch in, as opposed to engine braking. When I downshift and engine brake, it thinks I’m using more fuel (based on the RPMs?) then if i coast in neutral. I know this isn’t true because
A) When using a scanner app while driving, I use 0.2Gal/H when coasting in neutral, and 0 when engine braking
B) The engine is being spun by the force of the wheels, so it shuts off the fuel injection system
maybe the way the app calculates MPG isn’t right?

I think this is due that OBD2 does not send fuel cut information. When you are engine braking, RealDash still reads valid MAP and MAF values that computes to some consumption.

Hmmm… Is there any way to solve this? My scanner app can detect fuel citoff, so there must be some calculation or PID…

RealDash also has a TPS detection, is your TPS showing correct values?

tps works fine.

But that’s a completely different story.