Tempo V6-182 3.0L (1993)
Idle Speed: Adjustments
Curb and fast idle speeds are controlled by the Powertrain Control Module (PCM) and Idle Air Control (IAC) valve assembly. The IAC valve is not
adjustable. A large increase or decrease in closed plate airflow from the calibrated level will not allow effective idle speed control.
Throttle Body Assembly Decal Location
Throttle bodies with sludge tolerant design are identified with a yellow/black decal. This decal warns that the throttle plate stop screw must not be
adjusted counterclockwise (backed off), as this will not reduce the engine speed but may cause the throttle plate to stick in the bore. Backing out the
screw may be required if the throttle body has been previously serviced (a plug in the throttle plate orifice may be present), or (the plate stop screw
tampered with) (TP Self-Test output out of range). The decal also warns that the throttle body must NOT be cleaned inside the bore, as this cleaning will
impair the sensitive coating. The sludge accumulation will not affect the idle air flow. The cleaning procedure for the IAC valve still applies.
REMEMBER
Change in idle airflow can occur not only at the throttle body but other areas as well. You should enter the idle speed procedure only after other possible
causes in the following areas are eliminated:
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Battery and charging system integrity
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Contamination within the IAC component
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Lack of fuel system control (excessively rich or lean)
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Throttle sticking or binding
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Engine not reaching operating temperature
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Incorrect ignition timing
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Incorrect or clogged PCV system
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Vacuum leaks (intake manifold, vacuum hoses, vacuum reservoirs, power brake booster, etc.)
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Exhaust system, EGR.
VERIFY
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Transmission is in Park (A/T), or Neutral (M/T)
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Parking brake is applied (automatic brake release disconnected where applicable)
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Wheels blocked
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Heater, A/C, and other accessories Off
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Engine at operating temperature
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Proper fuel pressure and no exhaust smoke
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Correct and clean PCV system
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Ignition timing is set to specification
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EEC-IV diagnostics have been performed and vehicle malfunction indicated diagnostic trouble codes have been resolved.
PROCEDURE -
STAR tester or equivalent scanner required
STEP 1
Activate engine running Self-Test.
STEP 2
After Diagnostic Trouble Code (DTC) 11 or 111 has been displayed, unlatch and within 4 seconds latch the Self-Test Input (STI) button.
STEP 3
