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.
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HOMESERVICE MANUALSMERCURY1991TRACER BASE, 4D SEDAN, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 66 (ENGINE CONTROLS - SYSTEM/COMPONENT TESTS - EEC-IV (4.6L))IGNITION SYSTEMNOTES
1991 Mercury Tracer Base, 4D Sedan, Automatic
Ignition System: Notes
1991 Mercury Tracer Base, 4D Sedan, AutomaticSECTION Notes
WARNING: This page is about a different car, the 1994 Mercury Grand Marquis, 1994 Lincoln Town Car, 1994 Lincoln Mark VIII, and 1994 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
For additional information and descriptions, see IGNITION SYSTEM in THEORY/OPERATION - EEC-IV 4.6L
article in the ENGINE PERFORMANCE section.
IGNITION SYSTEM ACRONYMS
| Acronym (1) | Definition | ||||
|---|---|---|---|---|---|
| B + Or B (+) | Battery Positive | ||||
| B- Or B (-) | Battery Negative | ||||
| C1, C2, C3 | Coil Drive (Coils 1, 2 & 3) | ||||
| DI | Distributor Ignition System | ||||
| EI (2) | Electronic Ignition (High Data Rate Or Low Data Rate) | ||||
| FTO | Filtered Tach Output | ||||
| ICM | Ignition Control Module | ||||
| IDM | Ignition Diagnostic Monitor (Diagnostic Signal To PCM) | ||||
| IGND | Ignition Ground (Low Current Ground Reference) | ||||
| KOEC | Key On Engine Cranking (Testing Condition) | ||||
| KOEO | Key On Engine Off (Testing Condition) | ||||
| KOER | Key On Engine Running (Testing Condition) | ||||
| PCM | Powertrain Control Module (EEC-Processor, Computer, Processor) | ||||
| PIP | Profile Ignition Pick-Up (Camshaft Position Sensor Signal) | ||||
| PWR GND | Power Ground Circuit To ICM | ||||
| SPOUT | Spark Output (PCM Spark Control Signal) | ||||
| VPWR Or VBAT | Battery Power Or Battery Voltage | ||||
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IGNITION SYSTEM IDENTIFICATION
| Application | System | ||
|---|---|---|---|
| Crown Victoria, Grand Marquis & Town Car | (1) EI | ||
| Mark VIII | (1) EI | ||
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RENDER: 1.0x
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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.