Engine Controls - System/component Tests 3.0L: Diagnosis

Engine Controls - System/component Tests 3.0L: Diagnosis Mercury Villager I

Fuel Pump Testing

Visually inspect entire fuel delivery system for leaks and damaged or kinked lines and hoses. Ensure battery is fully charged and fuses are okay. Ensure adequate fuel is available in fuel tank.
Ensure ignition is off. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-23366-S05643198762001010300000). Install fuel pressure gauge between fuel filter and fuel rail. Turn ignition on to activate pump. Check and record fuel pressure. For 1995 fuel pressure specifications, see «FUEL PRESSURE SPECIFICATIONS»(/mercury/villager/i-1992-1998/remont/specifications/#fuel-pressure-specifications) article. For 1996 fuel pressure specifications, see «FUEL PRESSURE SPECIFICATIONS»(ref-123322) article. Replace fuel pump if not within specification.

Following equipment is recommended for testing

Following information should be noted during testing

Ensure 5-amp ENGINE fuse is okay.
All voltage readings given in test procedures are based on values obtained using a standard DVOM.
When instructed to inspect a wiring harness, perform both a visual inspection and a continuity test.
When making voltage checks, ground connections should be made at negative battery terminal or cast iron surface of engine.
When making measurements on a wiring harness or connector, perform a wiggle test while measuring.
When checking voltage, ground reading is defined as value of less than one volt. Battery voltage is defined as value of 10-14 volts.
DO NOT measure voltage or resistance at PCM. DO NOT connect any test light unless specified in testing procedure. All measurements are made by probing rear of connector.
Isolate both ends of a circuit and turn ignition off when checking continuity.
An open circuit is defined as a resistance reading of greater than 5 ohms. This specification tolerance may be too much for some items in EEC system. If resistance approaches 5 ohms, always clean suspect connector and coat it with protective dielectric silicone grease. A short is defined as a resistance reading of less than 10,000 ohms to ground, unless stated otherwise.
Test procedures are intended to identify faulty components or wiring while fault is present. If complaint is an intermittent condition, refer to «TESTS W/O CODES»(ref-23350) article in the ENGINE PERFORMANCE section.