What this node sets up
The Oil Metering Pump function decides how much oil the pump should deliver. The Wiring node is the hardware side: what kind of stepper motor you have, how fast and far it can move, which pins drive it and where the position feedback comes in. Get this right before you tune the target position table.
Options
| Setting | What it does | Our advice |
|---|---|---|
| Output Type | 4-wire or 6-wire stepper motor | Count the wires at the motor, not the loom |
| Stepper Max Speed | The fastest the motor is allowed to step | Too slow and it lags. Too fast and it skips steps, so the ECU loses track of where it really is |
| Stepper Range | How far the motor can travel | Too small and the pump never fully opens. Too large and the top of the range does nothing and calibration takes longer |
| Stepper Invert | Reverses the direction of travel | Use it if the pump moves the wrong way when commanded |
Connections
- Output: a 4-wire stepper must use the four half-bridge outputs (HBOs), because it needs current driven in both directions. A 6-wire stepper can use four DPOs or other suitable outputs.
- Drive Type: the Mazda stepper motor uses Low Side.
- Feedback Input: the pump position sensor goes to an analog voltage input (AVI).
Half-bridge outputs are also what drive by wire throttles and some idle valves need. On a 4-wire pump, check you still have enough HBOs for everything else before you commit to a pin plan.
Checking it works
With the engine off, command a few positions and watch the feedback follow. If the motor chatters or the feedback lags behind the command, lower the max speed. If feedback moves the opposite way to the command, try Stepper Invert. Then confirm full travel before starting the engine, because a pump that can't reach full delivery is a real risk to apex seals.
Rotary owners usually pair this with a plug-in ECU like the Nexus plug-in ECU for the RX-8. Running an Elite? See Oil Metering Pump for Elite. For help with a rotary build, contact us.
