New Weber Alpha (webcon) throttle position sensor for the DCOE range of carburettors. Part number 9990266000.This is designed to make 2D ignition mapping into 3D which is the ideal setup. It will work best with the Alpha engine management, but is also suitable formost other systems.
A kit is available for Weber DCO/SP 9990266800
Below are shown the fitting instructions for this kit which explains the ease of fitment.
Latest item now has a lead for connection rather than type shown in photo.
1. Remove the shaft nut and lock tab from the right hand side of the carburettor.
2. Fit the forked throttle lever in the orientation as shown in Fig.2. Refit the original lock tab and shaft nut.
3. Fit the throttle position sensor (TPS) mounting bracket in position and secure with two M5 mounting screws, Fig.3.
4. Fit the TPS using the two M4 mounting screws and cover plate as shown Fig.4. Ensure that the sensor lever sits within the fork of the throttle lever and that the sensor is seated fully into the mounting bracket.
5. Fit the three pin socket from the wiring loom to the TPS.
6. Peel back the rubber cover on the connector on the wiring harness so that a voltmeter can be connected to the pins whilst still connected to the TPS.
7. Loosen the two screws holding the TPS to the bracket and rotate the TPS fully anticlockwise, then retighten the screws.
8. Start the engine and allow it to reach its normal operating temperature. Set the carburettor idle speed and balance.
9. Connect the voltmeter to the following pins:
Negative to pin 2 (blue wire) and positive to pin 3 (red/green wire). The reading should be 5 Volts (±0.1 Volt).
10. Slacken the two screws holding the TPS to the bracket so that it can be moved easily, but is not so loose that it will slip out of position
11. Connect the voltmeter positive to pin 1 (purple/blue wire) and the negative to pin 2 (blue wire), and with the engine at idle turn the TPS clockwise
12. Tighten the screws and recheck the voltage.
13. Stop the engine and turn the ignition on. Hold the throttle fully open, the voltage should be at least 3.8V.
14. When the calibration is complete, disconnect the voltmeter and refit the rubber cover on the plug.
Alpha Harness Colours
Pin 1 Signal Purple/Blue
Pin 2 Ground Blue
Pin 3 5V Ref. Green/Red