So, I've been driving around checking out the values on the scangauge and I noticed that when I am going downhill, or anytime where the engine isn't pushing the transmission and the transmission is pushing the engine, the GPH goes to 0.00. Does this mean the engine is actually not using any fuel? If I am coming to a stop then when I get close to it, it will bring the GPH back up to 0.21 or so while I am still, idling. The car is a Scion 2008 xB automatic. What do you guys think?
Sounds like you have "fuel cutoff on deceleration" on your Scion. As for the GPH going back up, watch the RPM as you decelerate. As the RPM falls down to the same value as your normal "idle RPM", the fuel should be restored, because the ECU/PCM does not want the RPM to ever drop below the idle RPM. That's my 2 cents.
I have the same thing in m Honda civic. As with what cfg83 said, this is your fuel cut-off for your scion. I've been using that change to 0.00gph to help me determine my coast, and to tell me when i should down-shift. If I'm decelerating and the scangauge doesn't read 0.00gph or 9999mpg I'll down shift to D3 so the transmission will drop a gear or two and coast with the fuel cut-off. Although once you hit a certain speed the transmission will shift into a neutral state and the idle fuel consumption will return.
Aughhhhhh you lucky guys have the new software that knows when the engine goes into fuel cutoff and now shows it. I checked my email for the orders I had placed and found that I got my SGI in January and SGII around March of 2006 so no free upgrade - guess I have to fork out the $25 and wait a week+ shipping.
Yeah but it only shows one decimal place not two and it doesn't go to zero. Usually if the car is in gear with no gas applied it reads 0.2gph or greater if the RPM is higher and around 4000rpm it is about 0.4-0.6gph with no gas applied - fuel cutoff. This gives you an idea what the no load minimum fuel consumption is for the engine at those RPMs.
I recieved a reply from Ron at Linear-logic about the CUTOFF value found in the settings in the v3.15 scangauge II.
"The CUTOFF was a last minute addition to the ScanGaugeII. Some vehicles will report when they shut off fuel flow during coasting with the engine in gear. The same signal also indicates when the vehicle is enriching the fuel mixture during hard acceleration. If the throttle position is below the CUTOFF value when this signal is received, the ScanGaugeII assumes it means 0 fuel flow. Above this it means enriched flow. Normally you should not have to change this. If your TPS is above this level when you are coasting with your foot off the accelerator, you would need to raise it. If you set it to 0, this detection is turned off.
We are working on the Honda codes now. Can you tell us if the 06 Civic is CANSF or ISO? From the home screen, use MORE>MORE>MODE to see this on the top line.
So the CUTOFF function is dependent on the Tps value. However, Ron does mention that this should only be changed if your Tps reads higher that 24 during an in gear coast. I supposed the opposite could be true where if your Tps is below 24 during an in gear coast you can change the CUTOFF value to a number closer to what your Tps reads as long as it's above the Tps value while coasting in gear.