Why watch wastegate position?
Boost control logs normally show two things: the duty sent to the solenoid and the boost that resulted. What's missing is the bit in between, the wastegate itself. A position sensor fills that gap. With it in your logs you can see whether the gate is cracking open early and bleeding off spool, sticking, fluttering, or running out of travel at the top end. It's especially useful on electronic wastegates and on high-boost setups where the gate is working hard.
On the Elite, this input is for monitoring. It records what the gate is doing so you can diagnose it; the boost control strategy itself is set up separately in boost control.
Wiring it in
Assign each sensor on the Wiring tab under Wastegate Valve Position Input(s). Twin-gate setups can use one input per wastegate.
- AVI (Analogue Voltage Input): the one to use if you have a spare. Its pull-up is 1k to 5V.
- SPI (Synchronised Pulsed Input): a backup when AVIs run out. Set Sensor Type to Hall Effect so it reads the analog signal. Its pull-up is a weak 10k to 5V.
A position sensor is typically fed from the ECU's 5V supply and drives its own output, so leave the pull-up disabled. Pull-ups are intended for passive two-wire temperature sensors. If another controller is already reading the same sensor, it will already be providing whatever bias is needed, which is another reason to keep it off.
Calibration
You can set this sensor up two ways:
- Enter the end points yourself. Type in the voltage the sensor reads with the gate fully closed (0%) and fully open (100%). This is the method we use most, because it accounts for how your sensor is actually mounted.
- Load a calibration file. ESP includes preconfigured calibrations, loaded from the yellow Open icon. A custom calibration built from the sensor maker's data can be saved with the blue Disk icon for reuse.
To find your end points, read the raw voltage with the gate at rest (closed). Then open it fully, by applying pressure to the actuator or commanding an electronic gate open, and note that voltage too. Enter both, then move the gate by hand or with pressure and check the percentage tracks smoothly from 0 to 100.
If logs show the gate at or near 100% while boost keeps climbing, the gate is likely too small for the exhaust flow. If it never opens far even when boost overshoots, look at the actuator, its pressure feed or the control setup. Either way, that's valuable information before you add boost.
Quick troubleshooting
- Reading stuck near 0 or 5V: wrong input, broken signal wire or no 5V supply to the sensor.
- Percentage doesn't span 0-100: re-measure the closed and open voltages; the sensor may have moved on its bracket.
- Noisy trace: heat and vibration near the turbo are hard on sensors and wiring, so check the mounting and route the harness away from the exhaust.
You can also compare against a wastegate pressure sensor to see pressure and position side by side.
