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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 25 (Engine Controls - Tests W/Codes - 2.5L) >> No-Start Tests >> Test NS-3A - Inspecting Mechanical System

Test NS-3A - Inspecting Mechanical System

WARNING: This page is about a different car, the 1995 Plymouth Voyager, 1995 Plymouth Grand Voyager, 1995 Dodge Grand Caravan, and 1995 Dodge Caravan. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For circuit and connector terminal identification, see CONNECTOR IDENTIFICATION  . For wiring diagrams, see WIRING DIAGRAMS  section.
  1. Disconnect Manifold Absolute Pressure (MAP) sensor connector. Turn ignition on. Using scan tool, check voltage on MAP sensor connector Violet/White wire. If voltage is less than 4.5 volts, repair open Violet/White wire. Perform TEST VER-1.
  2. If voltage is more than 4.5 volts, reconnect MAP sensor connector. Remove all spark plugs. Inspect spark plug tips for wet fuel. If spark plug tips are wet, clean and reinstall spark plugs. Go to next step. If spark plug tips are not wet, reinstall spark plugs. Go to next step.
  3. Inspect spark plug cables for correct placement. Reposition wires as required. Perform TEST VER-1. If spark plug cables are okay, disconnect Engine Coolant Temperature (ECT) sensor connector. Connect timing light to engine. While cranking engine, check ignition timing using timing light. If ignition timing is not 0-16 degrees BTDC, go to step 5).
  4. If ignition timing is 0-16 degrees BTDC, turn ignition off. Check valve timing. Correct valve timing as required. Perform TEST VER-1. If valve timing is okay, check engine compression. Repair as required. Perform TEST VER-1. If engine compression is okay, replace MAP sensor. Perform TEST VER-1.
  5. Attempt to set ignition timing to specification listed on emissions label. If ignition timing cannot be set to specification, repair distributor misalignment. Perform TEST VER-1. If ignition timing can be set to specification, attempt to start engine.
  6. If engine starts, test is complete. Perform TEST VER-1. If engine does not start, turn ignition off. Check valve timing. Correct valve timing as required. Perform TEST VER-1.
  7. If valve timing is okay, check engine compression. Repair as required. Perform TEST VER-1. If engine compression is okay, repair engine mechanical problem. Perform TEST VER-1.
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