LH 2.4 Mixture Adjustment

This page contains information about LH 2.4 manual mixture adjustment (CO pot).



  • 1 - 2.5k linear taper potentiometer or trimmer
  • 1 - 'extra' pin for bulkhead connector
  • length of wire to place adjustment somewhere comfortable
  • Solder and soldering iron, heatshrink, etc

The default ohm resistance for zero adjustments is around 380 ohm.
This means the pot can go both positive (add) and negative(subtract)

  1. Unplug the bulkhead connector from your LH ECU (the 35 pin one). Note: Unplugging it becomes much easier if you remove the ECU from it's bracket first.

  2. On the downward-pointing narrrow end of the connector, there is a single phillips head screw. Remove the screw and then slide the plastic cover off, exposing the wires in the connector.

  3. Locate the spot for pin 23. It will be empty. The pin numbers are on the connector, but a flashlight is helpful when finding it.

  4. Remove the pink "pin guard" on the side with pin 23. It's pretty hard to miss. It's pink and runs the length of the connector. It should pull/fall out easily.

  5. Install your 'extra' pinned wire into location 23. There is only one correct orientation so take note of the other pins. The pin should be installed with the crimped side of the pin facing outwards so the stub of bare wire is visible. Slide the wire into the connector; it should latch and not come out easily.

  6. Replace the pink "pin guard" and then reinstall the connector cover and screw. Make sure that the wire we just installed is accessible outside the connector! You may have to extend it; if necessary use solder and heatshrink or electrician's tape.

  7. Extend the wire from LH to the point where you wish to mount the potentiometer. I would suggest somewhere in the glove box unless you like curious passengers playing with your AFRs.

  8. Solder the wire coming from LH to the "wiper" terminal from the potentiometer.

  9. Attach a wire to ONE of the remaining terminals on the potentiometer. Doesn't matter which. Then, attach the other end to a GOOD ground near the LH ECU. The spade-terminal ground block behind it is recommended.

  10. Start the car, and using your wideband adjust the potentiometer until your idle/cruise is where you want it!

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