JDS - Verifying Base Idle Speed Settings
88jaguar02SUBJECT: IDLE RPM, SLOW TO RETURN
MODEL: XJ6 3.6
NO.: 2-009
DATE: 3/10/88
When engine set up is selected JDS will perform a check to determine what specification Engine Management ECU is fitted. After JDS determines which ECU is fitted, a base idle speed specification will appear on its screen. The correct base idle speed settings are as follows:
^ P/N DBC 2911 -- 650-680 RPM
^ P/N DBC 3711 (low compression) 570-630 RPM DBC 3713 (high compression) 570-630 RPM - From VIN 521255
Note: The base idle speed JDS selects should always be checked against the part number of the ECU. If JDS selects the wrong specification, the specification markers on the JDS screen should be disregarded and base idle set to proper specification.
Base idle speed is the idle speed setting with idle speed control valve fully closed. JDS signals the valve to close when the measurement probe is attached to connector LI20 (water-temperature sensor) during an engine set up procedure. When probing connector LI20 during engine set up it should be ensured that the blue/yellow wire is chosen. Reports of wires being reversed in connector LI20 have been received. This will not affect operation of the vehicle, but will affect a JDS test.
If a complaint of "engine RPM slow to return to idle" is encountered, the following basic set up should be performed:
1. Check throttle plate gap is set to 0.002".
2. Set base idle speed to the low end of the specification (use JDS).
3. Set throttle potentiometer (use JDS).
4. Set idle co (use JDS).
Information regarding success using the base idle set up procedure, or any aspect of an idle speed slow to return to normal condition should be reported by PQR.