Sensors & outputs Trigger
36-1 trigger wheel
Missing-tooth crank disc · sensor · Trigger
Thirty-five teeth and one gap. TunerStudio’s toothed-wheel decoder treats that gap as the index. The disc itself has no wires. The pickup is either a two-wire VR sensor or a three-wire Hall sensor.
Typical parts: 36-1 crank disc (steel, centre bore to suit the damper or crank pulley)
Device pinout
The diagram is the tooth pattern and the pickup landing, looking at the rim with the sensor aimed at the gap. There is no locking tab on a wheel.
- Connector: none on the wheel
- Pickup: Crank VR or Crank Hall
| Device pin | Function | Type | Race Core | TunerStudio |
|---|---|---|---|---|
| VR + | Crank VR+ | Signal | B5 | VR 1+ |
| VR − | Crank VR− | Ground | B13 | VR 1− |
| Hall signal | Crank Hall signal | Signal | B10 | Digital 1 |
| Hall ground | Sensor ground | Ground | C1–C8 / C29 / C31 | Sensor GND |
| Hall supply | 12 V or 5 V, per the sensor | 12 V | C11 / C23, or 5 V Sens 1 | 12 V Sens or 5 V Sens 1 |
Wiring notes
- Use one pickup. A VR sensor on Digital 1, or a Hall sensor on VR 1, will not decode.
- Air gap about 0.5–1.0 mm, sensor square to the teeth, bracket rigid. A gap that opens with rpm walks the timing.
- The missing tooth must pass the sensor once per crank revolution. A wheel drilled for a cam (half speed) is the wrong disc.
- Shield a VR pair to sensor ground at the ECU end only. Twisted pair. Keep it off the coil and injector runs.
- TunerStudio: 36-1 toothed wheel on the primary trigger. Rising edge on the usual MAX992x VR input. If the composite log shows a long-low then long-high pair, swap VR+ and VR−. Do not “fix” that with Invert.
- Sequential injection still needs a cam. The 36-1 gap identifies crank angle, not which revolution you are in. Cam Hall is Digital 2 (B1), or cam VR is B4 / B12.
- Trigger offset is a timing-light job on cylinder 1. The wheel’s missing tooth can sit anywhere relative to TDC; offset absorbs that. It does not absorb inverted polarity.
Failure modes
- Cranking rpm 0: gap too large, sensor on the wrong input type, or the missing tooth is not in the sensor’s path.
- Cranking rpm in the thousands: double-edged VR, or a Hall sensor with the pull-up off so both edges count.
- Timing walks with rpm: soft bracket, wrong gap, or a VR pair routed with the coil harness.
- Sync loss once per two revolutions: that is a cam problem, not a bad 36-1 wheel.