Live data: what to look at first
Sixty-seven parameters is a lot. Here are five that answer most questions about how the engine feels.
The app can show 67 parameters and remembers the highest and lowest value of each trip. There is no need to watch them all — start with five.
1. Fuel trims
The most telling reading. On a healthy car they stay near zero. A large plus means the unit is adding fuel: there is extra air somewhere, or not enough rail pressure.
2. Coolant temperature
It should reach operating temperature and stay there. If it wanders, start with the thermostat, not the water pump.
3. Oxygen sensor readings
On a warm engine the voltage of the front sensor keeps changing — that is normal work. A sensor frozen at one value is lying.
4. Engine load
Useful on the motorway: if load at a steady speed on a flat road grows from trip to trip, something is holding the car back — from a dragging brake caliper to a clogged filter.
5. System voltage
14.0–14.6 V with the engine running. Lower — check the alternator; higher — the voltage regulator.
The app polls the car several times per second and draws a graph, so you see not just the level but how the reading answers the throttle.
