Diagnostic Aids

1993 Ford Pickup F250, 2D Pickup, 5.0 N, Standard, M5OD-R2SECTION Diagnostic Aids
WARNING: This page is about a different variant/trim than selected.

Perform this test when checking computed timing or if directed by QUICK TEST. This test is intended to diagnose:

  • SPOUT wiring harness circuit.
  • Base timing.
  • Powertrain Control Module (PCM).

To prevent replacing good components, be aware the following non-EEC related areas may be at fault:

  • Basic engine condition (compression, valve timing, etc.).
  • Distributor.
  • Ignition Control Module (ICM).

Fig 1: Spark Timing Check Circuit
G93C40768
TEST PIN NO. 36 (SPOUT) WIRE COLOR ID

Application Wire Color
All Models Pink
  1. Check For Power To PCM  Turn ignition off. Disconnect 60-pin PCM connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Turn ignition on. Measure voltage between test pins No. 37 and 40 and between test pins No. 57 and 60 at breakout box. If either voltage reading is less than 10.5 volts, go to CIRCUIT TEST B . If both voltage readings are 10.5 volts or more, go to step 2).
  2. Check SPOUT Circuit For Continuity  Turn ignition off. Disconnect ICM wiring harness connector. Measure resistance between test pin No. 36 at breakout box and SPOUT terminal at ICM wiring harness connector. If resistance is more than 5 ohms, repair open circuit. Reconnect all components, and check ignition timing. If resistance is 5 ohms or less, go to step 3).
  3. Check SPOUT Circuit For Short To B+  Turn ignition off. Leave PCM and ICM disconnected. Turn ignition on. Measure voltage between test pin No. 36 and test pins No 40 or 60. If voltage is more than 10.5 volts, repair short circuit and repeat QUICK TEST. If voltage is 10.5 volts or less, go to step 4).
  4. Check SPOUT Circuit For Short To PIP, VREF & Ground  Turn ignition off. Leave PCM and ICM disconnected. To check for shorts to VREF, use DVOM to measure resistance between test pins No. 26 and 36 at breakout box. To test for shorts to PIP, measure resistance between test pins No. 36 and 56 at breakout box. If either resistance is 10,000 ohms or less, repair short circuit and repeat QUICK TEST. If each resistance is more than 10,000 ohms, EEC system is okay. Check ignition system. See IGNITION SYSTEMS in I - GAS SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
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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.