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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 43 (Engine Controls - Tests W/Codes - 8.0L) >> Self-Diagnostic Tests >> Test NTC-2A - Checking Secondary Ignition & Timing

Test NTC-2A - Checking Secondary Ignition & Timing

WARNING: This page is about a different car, the 1995 Dodge Pickup and 1995 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn engine off. Connect engine analyzer to engine. Start engine, and let it idle. If engine will not idle, maintain a constant RPM above idle. Set scope to read display or parade pattern. Follow equipment manufacturer's procedure for pattern analysis.
  2. If secondary ignition pattern is not okay, repair indicated component in secondary ignition system. Perform TEST VER-2. If secondary ignition pattern is okay, momentarily disconnect each spark plug wire from ignition coils. Observe secondary kilovolt line.
  3. If open circuit secondary voltage is not at least 25 kilovolts, replace ignition coil. Perform TEST VER-2. If open circuit secondary voltage is at least 25 kilovolts, turn engine off.
  4. Remove all spark plugs. Check engine compression. If all cylinders do not have a minimum compression of 100 psi (7.0 kg/cm2 ) and are not within 25 percent of each other, repair engine as necessary. Perform TEST VER-2.
  5. If engine compression is okay, reinstall spark plugs. Start engine. Ensure engine temperature is more than 180°F (82°C) before proceeding. Using scan tool, read total timing advance. Increase engine speed to 2000 RPM. If timing advance does not change with increase in RPM, replace Powertrain Control Module (PCM). Perform TEST VER-2. If timing advance changes with increase in RPM, ignition timing is functioning properly. Test is complete.
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