Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Test Mm - Spark Timing Check
To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: engine condition (valves, vacuum leaks, valve timing, EGR valve, etc.), PIP sensor, TFI ignition module.
- Perform ENGINE RUNNING SELF-TEST and verify that SELF-TEST is activated. Check and record timing while in ENGINE RUNNING SELF-TEST. System locks timing then returns to normal 2 minutes after last service code is displayed. If timing is 27-33°, spark timing is correct. Go to ENGINE RUNNING SELF-TEST. If timing is not 27-33°, go to next step.
- Locate Spark Output (SPOUT) connector and open the connection. Start engine and check for 10° BTDC base timing F 3°. If base timing is correct, go to next step. If base timing is not correct, adjust base timing. After timing is adjusted, connect SPOUT and perform TIMING CHECK . See TIMING CHECK in QUICK TEST (ALL VEHICLES) section of this article.
- Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box. Turn key on, leaving engine off. With DVOM on 20-volt scale, measure voltage between test pin 37 and 40, and between test pin 57 and 60. If either reading is less than 10.5-volts, go to TEST UU - IRCM , step 1). If both readings are 10.5-volts or more, go to next step.
- Turn key off and wait 10 seconds. Disconnect harness connector at TFI module. With DVOM on 200-ohm scale, measure resistance between test pin 36 and pin 2 (SPOUT circuit) at TFI harness connector. If reading is greater than 5 ohms, repair open circuit. Connect SPOUT connector and check timing as described in step 1). If reading is 5 ohms or less, go to next step.
- Leave breakout box installed and TFI harness disconnected. Turn key off and set DVOM on 200-ohm scale. Measure resistance between test pin 16 and pin 6 (IGN GRND circuit) at TFI harness connector. If reading is less than 5 ohms, go to TEST A - NO START , step 7). If reading is 5 ohms or more, repair harness as necessary and repeat QUICK TEST .
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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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