User manual BENDIX ET-2 ELECTRONIC THROTTLE

[. . . ] ® Bendix® ET-2TM Electronic Treadle TREADLE COVER system by changing resistance, returning more or less of the supplied voltage back to the electronic engine controller. If the driver does not request engine power, the throttle is in the idle (or "closed throttle") position. In this state, the potentiometer significantly reduces the amount of supply voltage returned to the engine control unit (See Figure 2). As the driver depresses the ET-2TM treadle, output voltage increases (see Figure 3). [. . . ] Calculate the "switch point percentage" using the formula below. Switch point percentage = ((Vx-V1)/(V2-V1))*100 Vx = Output voltage when the switch changed V1 = idle voltage V2 = full throttle voltage The following instructions are for a bench test for the potentiometer used with Cummins engines. Unplug the cable assembly from the potentiometer's integral connector by lifting the lock tab and pulling the connectors until they disengage. Inspect cable assembly for loose terminals, frayed wires, corrosion, wear, or physical damage. Check end-to-end electrical continuity at terminals. NOTE: Potentiometer pin locations will remain constant (see Figure 5). However, cable assembly connector pin out may vary from engine to engine. Remove the ET-2TM treadle from the vehicle. Secure the ET-2TM treadle to a smooth, flat surface in such a way that it does not twist the unit. Connect the potentiometer to the volt meter and power supply as shown in Figure 5. NOTE: Power supply can be a 12 VDC vehicle battery in good condition and with known voltage output. Verify that the closed throttle (idle) output voltage, as a percentage of supply voltage, is within the limits listed in Figure 2. Depress the treadle to its full throttle position. The output voltage, as a percentage of supply voltage, should be within the limits listed in Figure 2. Testing a Detroit Diesel ET-2TM Treadle Potentiometer: Battery = 10 VDC. Make several full applications and record idle position voltage each time. Verify that idle position voltage does not vary by more than . 4% (. 02 volts). If the ET-2TM treadle does not operate within its specified ranges, service the unit, or replace it with a new ET-2TM treadle, available at your nearest Bendix parts outlet. Test 3: For Cummins engines (with integrated switch and sensor (ISS): For use only with the Cummins Celet Plus and later editions of the ECU. This sensor can not be used to replace the separate potentiometer & idle validation switch. To do this a new ET-2TM treadle with the ISS must be purchased. Test 1: Where the set resistance and voltage is shown on a label. [. . . ] Install the pivot spring (11) into the base and treadle. The curved end of the spring fits into a small hole in the treadle, and the straight end fits into a small hole in the mounting base. The pivot pin (9) should slide through the holes in the "ears" of the treadle and base assembly, then through the center of the spring. Make sure the pivot spring is straight and is seated in its holes. 5. [. . . ]