POTENTIOMETER SETTING PROCEDURE IN FIELD

Aim: The purpose of this document is to provide setting procedure for potentiometer in the field.

Description: Throttle lever potentiometer is an important part of the fuel injection pump which is

used to provide throttle lever position to the ECU. The position input is used by the ECU for

deciding the EGR operation (in DPC pumps with AECU) and injection timing & EGR (in case of

DPCN system with Delphi ECU)

The potentiometer is a very important part of the system and its setting is done on a very

precise FIP test rig under controlled conditions. The potentiometer should not be tampered under

any condition without proper diagnosis.

Setting procedure: The clip on the throttle lever is punched with a voltage value which is the

setting reference for the potentiometer. When there is a need for checking the potentiometer

functioning, potentiometer tester (Part no: POT-01) must be used. (Picture 1 & 2)

Picture 1 Picture 2

Step 1: Connect the electrical connector of the potentiometer to the pot tester. Also connect the

positive and negative connections of the tester to the battery terminals.

Step 2: Move the throttle lever from minimum to maximum and notice the change in voltage

display. If potentiometer value remains constant while moving the throttle lever from minimum to

maximum position go to Step 3 otherwise Step 4.

Step 3: Remove the potentiometer from the mounting bracket and clean it using air. Check the

connector for damage and oxidation. Clean the connector and again check voltage in

potentiometer removed condition. If voltage varies from minimum to maximum, assemble the

potentiometer into the bracket. If not, replace with new potentiometer. Use caution during

assembly of potentiometer. Ensure during assembly that the lever on the potentiometer is located

properly in the slot provided in the throttle lever.

Step 4: Remove the cable guide from the FIP rear support bracket. Assemble the fixture (FMX-

0751) which is a part of the pot tester kit on the rear support bracket and other end to the

throttle lever ball. (Picture 3 & 4)

Picture 3 Picture 4

Step 5: Check whether the value shown on the display of the pot tester matches with that of the

clip value. (Picture 5) If it matches, then the potentiometer and its setting are good. In case of

mismatch of the potentiometer value, unscrew the potentiometer and turn it till voltage matches

with the clip value. Tighten the potentiometer in this condition.

Picture 5

Clip value

Fixture fitted on Throttle lever ball