Diagnosing Electronically Controlled Fuel System Problems; Troubleshooting Charts; Starter Motor Will Not Crank Engine, Or Cranks Slow; Engine Will Not Start, Or Is Hard To Start - Mercury TDI 3.0L Owner's Operation And Maintenance Manual

Section 6 - Troubleshooting

Diagnosing Electronically Controlled Fuel System Problems

Your Mercury Diesel authorized repair facility has the proper service tools for diagnosing problems on electronically controlled
fuel systems. The engine control module on these engines has the ability to detect some problems with the system when they
occur, and store a trouble code in the control module's memory. This code can then be read later by a service technician using
a special diagnostic tool.

Troubleshooting Charts

Starter Motor Will Not Crank Engine, or Cranks Slow

Possible Cause
Battery switch turned off.
Remote control not in neutral position.
Open circuit breaker or blown fuse.
Loose or dirty electrical connections or damaged wiring.
Bad battery.

Engine Will Not Start, or Is Hard to Start

Possible Cause
Lanyard stop switch activated.
Improper starting procedure.
Empty fuel tank or fuel shut off valve closed.
Faulty mechanical fuel delivery pump.
Throttle not operating properly.
Faulty electrical stop‑circuit.
Clogged fuel filters.
Stale or contaminated fuel.
Fuel line or tank vent line kinked or clogged.
Air in fuel injection system.
Faulty wire connections.
Glow plugs or glow plug system inoperative, if
equipped.
Electronic fuel system fault.

Engine Runs Rough, Misses, or Backfires

Possible Cause
Throttle not operating properly.
Idle speed too low.
Clogged fuel or air filters.
Stale or contaminated fuel.
Kinked or clogged fuel line or fuel tank vent line.
Air in fuel system.
Electronic fuel system faulty.
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Turn switch on.
Position control lever in neutral.
Check and reset circuit breaker or replace fuse.
Check all electrical connections and wires (especially battery
cables). Clean and tighten faulty connection.
Test and replace if bad.
Check lanyard stop switch.
Read starting procedure.
Fill tank or open valve.
Have pump replaced by a Mercury Diesel–authorized repair facility if
fuel is present.
Check the throttle for freedom of movement.
Have a Mercury Diesel–authorized repair facility service the electrical
stop circuit.
Replace the filters.
Drain tank. Fill with fresh fuel.
Replace kinked lines or blow out the lines with compressed air to
remove obstruction.
Purge fuel injection system.
Check wire connections.
Have a Mercury Diesel–authorized repair facility service the glow plug
system.
Have the electronic fuel system checked by a Mercury Diesel–
authorized repair facility.
Check the throttle for binding or an obstruction.
Check idle speed and adjust, if necessary.
Replace the filters.
Drain tank and fill with fresh fuel.
Replace kinked lines or blow out lines with compressed air to remove
obstruction.
Purge fuel injection system.
Have electronic system checked by a Mercury Diesel–authorized repair
facility.
Remedy
Remedy
Remedy
90-8M0145546 MAY 2018
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