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Home >> Plymouth >> 1981 >> Arrow Pickup Base, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Idle Enrichment System >> Testing >> System Test
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System Test

  1. With engine at normal operating temperature, remove air cleaner but DO NOT cap any vacuum fittings opened by hose removal (leakage needed for test).
  2. Disconnect hose to idle enrichment valve at plastic connector (connector has a filtered bleed which will interfere with test, so it must be removed). Start engine place fast idle screw on slowest step of fast idle cam. Connect 3-4' length of hose to enrichment valve.
  3. Apply vacuum with a hand pump to end of hose and listen for engine speed change. If engine speed can be controlled by vacuum, diaphragm and air valve are operating correctly. If speed cannot be controlled by vacuum, replace valve assembly (Holley carburetors) or proceed to next step (Carter carburetors).
  4. Place finger on the other plug over air inlet passage and listen for engine speed change. If speed can be controlled, diaphragm is leaking or air valve is stuck open. If speed cannot be controlled, air valve is stuck closed. Clean air valve or replace diaphragm as necessary.
NOTE: In the following procedure on some vehicles, timing module and solenoid valve serve a dual function of controlling both EGR delay and idle enrichment duration.
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