The custom datalogging routine programmed into a VAST ECU outputs 45 parameters from the ECU at 20-25 samples a second. 26 of these parameters are available for viewing in the Data Dash.
This is a view of the ‘Data Dash’ available while datalogging. The Data Dash provides a graphical view of the most important data items while datalogging.
- TCV duty cycle is the effective amount of time that the TCV spends closed, higher duty cycle = more boost.
- Load is a number which is measure in milliseconds, and is eventually converted to injection time. Load is an indicator of how ‘hard’ the engine is working and is very closely tied to the amount of air the engine is ingesting.
- System Voltage is the current voltage at the ECU.
- Air Mass is the amount of air that the MAF sensor currently detects.
- Map Set indicates the current alternate map set which is selectable via the TPS.
- O2 voltage is the voltage from the front O2 sensor.
- Injection Time is the amount of on time, in milliseconds, of each individual injector.
- TPS is the throttle position sensor.
- LTFT_I, LTFT_PL AND STFT Based on your front O2 sensor voltage, if the voltage is above .5V the ECU subtracts fuel, if the voltage is below .5V the ECU adds fuel. This number is reflected in STFT (short term fuel trim), this number shows the instantaneous amount of fuel being added at that moment. If this number stays too far on either side of 0, then the ECU knows that it needs to make a permanent adjustment to the fueling. The ECU has two variables it uses for this adjustment, called long term fuel trims they are applied at idle and part load. The LTFT_I has units of microseconds, and changes how long the fuel injectors stay open. LTFT_PL is a percentage and changes the percentage of how much fuel is injected.
- Gear Indicator On manual transmission cars this will show the current gear, on autos this values can be ignored
- Boost indicates the manifold absolute pressure reading from the vacuum sensor in the ECU. -2inHg = -1psi
- Wideband is the reading from the output of your wideband.
- XAFLT1-XFALT5 represent timing pull on an individual cylinder basis. For each knock event detected 2.25 degrees is pulled from that respective cylinder.
- Knock Sum is the sum of timing pull across all cylinders.
- Injector Duty Cycle is how long the injector spends ‘on’ or injecting fuel. Running an injector above 100% results in not enough fuel being delivered and a possible lean condition. It is not recommend to run an injector above 90% duty cycle due to the potential of overheating and having the injector stick open.