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Home >> Ford >> 1989 >> Probe L4-133 2.2L SOHC >> Repair and Diagnosis >> Powertrain Management >> Tune-up and Engine Performance Checks >> Idle Speed >> Adjustments
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Idle Speed: Adjustments

IDLE SPEED
TURBO
NOTE: The idle speed is controlled automatically by the ECA through the Idle Speed Control (ISC) Solenoid Valve, usually it is not necessary to check and adjust the idle speed. However, the idle speed should be adjusted when rough idling occurs when the Self-Test Input (STI) connector is grounded.

Before adjusting the idle speed, make sure the ignition timing is adjusted to specifications and check the general condition of the engine (i.e. leaks in hoses, plugs, etc.)

NOTE: For idle speed refer to SPECIFICATIONS.

1. Turn OFF all unnecessary electrical loads. this adjustment must be done while the radiator cooling fan is not operating.
2. Warm up the engine and it run for 3 minutes at 2,500-3,000 rpm in NEUTRAL (N) - MTX or PARK (P) - ATX.
3. Attach a tachometer to the engine and check the idle speed is within specification.
4. Ground the STI connector with a jumper wire.
5. If the idle is not within specification, remove the blind cap from the throttle body and adjust it by turning the idle air adjust screw.
6. After adjusting the idle speed, install the blind cap, disconnect the jumper wire from the STI, and remove the tachometer from the engine. If idle problem still exists check for other possible causes.


IDLE MIXTURE: Due to the automatic compensation function for the air/fuel mixture is built into the ECA, it is not necessary to check and adjust the idle mixture.


NON-TURBO
IDLE SPEED

1. Disconnect Idle Speed Control-Air Bypass Solenoid.
2. Place automatic transmission in PARK.
3. Start engine and run at 1500 rpm for 20 seconds.
4. Check/adjust idle to 650 +/- 25 rpm.
Turn the throttle plate stop screw to 600 +/- 25 rpm.
5. Engine OFF reconnect Idle Speed Control Air Bypass Solenoid, verify the throttle is not stuck in the bore and linkage not preventing throttle from closing.
6. Start engine and stabilize for 2 minutes then goose the engine and let it return to idle, lightly depress and release the accelerator and let engine idle. If idle problem still exists check for other possible causes.


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