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Home >> Jaguar >> 1990 >> Sovereign L6-4.0L >> Repair and Diagnosis >> Powertrain Management >> Tune-up and Engine Performance Checks >> Idle Speed >> Adjustments
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Idle Speed: Adjustments

NOTE: Base idle speed should be set using Jaguar Diagnostic System (JDS) equipment. If JDS equipment is not available, use the manual method described here.

1. Warm engine to operating temperature above 185°F (85°C).
2. Switch ignition "OFF."
3. Switch ignition "ON," wait 5 seconds and unplug idle speed controller connector. Controller is on intake manifold, left side of engine between 2nd and 3rd injectors.
4. Switch ignition "OFF."
5. Wait 15 seconds and reconnect idle speed controller.
6. Repeat previous steps twice. The second time through, do not reconnect idle speed controller.
7. Start engine.
8. Base idle should be approximately 550 - 600 rpm. If not, adjust air bypass screw to bring idle speed within specification.
9. Switch ignition "OFF" and reconnect controller.
10. Start engine and ensure that idle speed is 650 - 800 rpm.
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