1990 Jeep WagoneerFACTORY OEM SERVICE PROCEDURE

Functional Test

  1. Insert positive voltmeter lead into Blue wire at distributor connector. Install negative lead into Gray wire with tracer at distributor connector. Set voltmeter on 15 Volt A/C scale. Turn ignition on.
  2. Voltmeter should show approximately 5.0 volts. If there is no voltage, check leads for good connection. If there is still no voltage, remove ECU and check for voltage at pin C-16 with harness connected.
  3. If there is still no voltage, perform vehicle test using DRB-II. If voltage is present, check continuity between Blue wire at distributor connector and pin C-16 at ECU. If there is no continuity, repair harness as necessary. Check for continuity between Gray wire with tracer at distributor connector and pin C-5 at ECU. If there is no continuity, repair harness as necessary. Check continuity between Black wire at distributor connector and ground. If there is no continuity, repair harness as necessary.
  4. Set voltmeter to low AC scale. While observing voltmeter, crank engine. Voltmeter needle should fluctuate back and forth while engine is cranking. This verifies that stator in distributor is operating properly and a sync pulse (signal) is being generated. If there is no sync pulse, replace stator.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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