Ford Falcon EA-AU, Known Issues and Common Problems
Overview
The Ford Falcon EA (1988-1991), EB (1991-1993), ED (1993-1994), EF (1994-1996), EL (1996-1998), and AU (1998-2002) share the 4.0-litre SOHC inline-six engine platform, a tough, understressed design that routinely covers 300,000 km or more with basic maintenance. These engines were built for the demands of Australian conditions: long highway runs, extreme heat, and minimal servicing.
However, these cars are now decades old. The failures below are patterns of age and wear rather than fundamental engineering deficiencies. The good news is that the SOHC six is one of the most straightforward engines to work on, parts are plentiful and affordable, and the owner community has documented solutions for virtually every issue.
Engine
TFI Module Failure (EA-ED)
What happens: The engine cuts out while driving and won’t restart. After cooling for 30-60 minutes, it may restart and run normally for a while before dying again. Sometimes fails permanently.
Why it happens: The Thick Film Ignition (TFI) module is mounted on the distributor, directly exposed to engine heat. The module’s internal solder joints crack from thermal cycling. This is a design flaw, the module should never have been heat-soak mounted. Bosch designed the unit; Ford Australia (via Motorcraft) just relabelled it.
How to fix it: Replace the TFI module. Genuine Motorcraft units are the most reliable but increasingly hard to find. Aftermarket Bosch units are available ($80-150). Some owners relocate the TFI module away from the engine using an extension harness to reduce heat exposure. Carry a spare in the glovebox, this is the number one stranding failure on EA-ED Falcons.
Severity: Urgent. Failure stops the engine completely.
Hydraulic Lifter Tick (AU especially, all models)
What happens: A ticking or tapping noise from the top of the engine, often worst on cold start. May persist for minutes or be constant. The noise comes from the rocker cover area.
Why it happens: The hydraulic lash adjusters (HLAs) wear internally and lose their ability to maintain zero valve lash. Oil quality and change intervals directly affect lifter life. The AU seems most susceptible, though all SOHC Falcons can develop this issue at high mileage.
How to fix it: Replace all 12 lifters. The job requires removing the rocker assembly, unbolt the rocker shaft pedestals evenly (one turn at a time, outside to centre), remove the assembly, and use a pin punch and small hammer to tap out each lifter. Install new lifters greased on the outside, with the shim slot facing upward (oil feed). Reassemble centre to outside, torque pedestal bolts to 22 Nm. The job takes 4-6 hours. Parts: $180-250 from aftermarket suppliers. Ford charges $82 each ($984 for a set).
Severity: Needs attention. Ticking lifters reduce valve opening and performance. Severe cases can damage camshaft lobes.
Coil Pack Failure (EF-EL)
What happens: Misfiring on specific cylinders, rough idle, loss of power. May be intermittent initially, then become constant.
Why it happens: The EF and EL use a waste-spark coil pack (three coils firing six cylinders). Heat and age cause internal insulation breakdown in individual coil towers.
How to fix it: Replace the coil pack. Use new spark plug leads at the same time, old leads can damage a new coil pack through increased resistance. Cost: $100-200 for the coil pack, $50-80 for leads.
Severity: Needs attention. Sustained misfiring damages the catalytic converter.
Crank Angle Sensor Failure (EA-ED)
What happens: Engine cranks but won’t start, or starts and dies. No spark at all cylinders.
Why it happens: The crank angle sensor (CAS) on EA-ED models is located in the distributor. The sensor’s magnetic pickup weakens with age, or the toothed reluctor wheel develops corrosion.
How to fix it: Replace the crank angle sensor. On EA-ED, this requires partially disassembling the distributor. Set timing to top dead centre (TDC) on cylinder #1 before removing the distributor. When reinstalling, ensure the rotor points to the #1 lead position. Cost: $60-120.
Severity: Urgent. The engine will not run without a functioning CAS.
Idle Speed Control (ISC) Valve Issues
What happens: Erratic idle speed, high idle (1,500+ rpm), stalling when coming to a stop, or inability to maintain idle.
Why it happens: The ISC valve (also called the idle air control valve) clogs with carbon deposits from PCV system blowby. The valve is an electric stepper motor that controls idle air bypass.
How to fix it: Remove and clean the ISC valve with carburettor cleaner. Reset the base idle by: (1) Remove ISC plug, (2) Insert 0.75 mm feeler gauge between the throttle stop tab and throttle lever, (3) Put the engine in diagnostic mode, (4) Wait 2 minutes and adjust the throttle blade screw until idle reads 700 rpm (+/- 50). Cost: free if cleaning works; $80-150 for a new ISC valve.
Severity: Needs attention. Stalling at intersections is dangerous.
Rocker Cover Bolt Breakage
What happens: A rocker cover bolt snaps during routine maintenance, leaving the threaded portion stuck in the head.
Why it happens: The bolts are small and the aluminium head threads are soft. Over-torquing or corrosion causes the bolt to shear. Rocker cover bolt torque is 17 Nm, surprisingly light.
How to fix it: Use a screw extractor (easy-out) to remove the broken bolt. If the threads are damaged, a helicoil repair is necessary. Take extreme care during removal, if the broken bolt is forced and the thread strips, the head requires professional repair.
Severity: Minor annoyance, but can escalate to needs attention if threads are damaged.
Fuel System
Fuel Pump Failure
What happens: Engine cranks but won’t start. No fuel pressure at the rail. The fuel pump may be silent (normally an audible whine for 2 seconds when the ignition is turned to ON).
Why it happens: The in-tank electric fuel pump wears from age and debris. Running the tank low regularly accelerates failure by exposing the pump to air. Corroded electrical connections at the fuel pump plug compound the problem.
How to fix it: Replace the fuel pump. Access requires dropping the fuel tank (no access panel on EA-EL). Stock fuel pump pressure is approximately 270 kPa. Replace the fuel filter at the same time. Cost: $120-200 for the pump, plus labour for tank removal.
Severity: Urgent. The car will not run.
Fuel Pump Relay Failure
What happens: No-start condition, identical symptoms to fuel pump failure, but the pump is fine.
Why it happens: The fuel pump relay contacts corrode or weld together. The relay is located in different positions depending on the model year, under the dash, behind the kick panel, or in the engine bay relay box.
How to fix it: Replace the fuel pump relay. Keep a spare in the glovebox. Cost: $30-50. Locate the relay before you need it, finding it on the side of the road in the dark is not ideal.
Severity: Urgent. The car will not start.
Fuel Pressure Regulator Leak
What happens: Rich running, black smoke, fuel smell, poor starting, rough idle. Fuel may be visible in the vacuum line connected to the regulator.
Why it happens: The diaphragm inside the fuel pressure regulator tears. Fuel leaks into the intake manifold through the vacuum line.
How to fix it: Replace the fuel pressure regulator. Standard pressure is 270 kPa (39 psi) for EA-ED; the XR6 uses a 300 kPa (43 psi) regulator. They are not interchangeable without retuning. Cost: $60-100.
Severity: Urgent. Excess fuel creates fire risk and destroys the catalytic converter.
Cooling System
Heater Tap Failure (EF-AU)
What happens: Coolant leaks from the heater tap onto the engine or firewall. Loss of heating or cooling capacity. Coolant smell inside the cabin.
Why it happens: The vacuum-operated heater tap uses a rubber diaphragm that perishes with age. Once it fails, coolant leaks externally.
How to fix it: Replace the heater tap. Cost: $40-80. The job takes 1-2 hours. Replace the heater hoses at the same time if they’re original.
Severity: Needs attention. A leaking heater tap loses coolant and can cause overheating.
Thermostat Failure
What happens: Engine overcools (gauge sits on L) or overheats. Temperature gauge may swing between L and normal erratically.
Why it happens: Thermostats stick open or closed with age. The factory thermostat is typically 82°C.
How to fix it: Replace the thermostat. Cost: $20-40. Install with the jiggle pin at 12 o’clock for proper air bleeding.
Severity: Urgent if overheating. Needs attention if overcooling (affects fuel economy and heater output).
Expansion Tank Overpressure (EL)
What happens: Coolant pours from the expansion tank overflow after the engine is turned off. The temperature gauge reads erratically, may show L, then O, then back to L during a single drive.
Why it happens: Usually caused by overfilling the expansion tank (fill to the lower mark when cold, not the brim), a stuck thermostat, a faulty radiator cap (not holding pressure), or in worst cases, a cracked head allowing combustion gases into the cooling system.
How to fix it: First, fill the expansion tank correctly (to the lower mark when cold). Replace the thermostat and radiator cap. If the problem persists, test for combustion gases in the coolant using a block test kit. A cracked head requires professional repair ($1,000-2,000).
Severity: Needs attention. Investigate before assuming the worst, overfilling is the most common cause.
Transmission
BTR 4-Speed Automatic Failure (all models, AU worst)
What happens: Harsh shifts, slipping, delayed engagement, shudder during 2-3 shift. The AU frequently enters limp mode (stuck in 3rd gear only).
Why it happens: The BTR 4-speed uses clutch packs and bands that wear with age and heat. The AU Series 1 auto is the weakest variant. Contaminated or burnt fluid accelerates wear. The transmission control module can develop electrical faults causing limp mode (fault code P0748).
How to fix it: Start with a fluid and filter service ($150-250). If problems persist: shift kit ($200-400 fitted) improves shift quality and extends life. A rebuild costs $1,500-3,000. Alternatively, a manual conversion using a wrecking yard T5 transmission is popular ($1,000-2,000 all-in for a DIY conversion).
Severity: Needs attention. Ignoring deteriorating shift quality leads to complete transmission failure.
Electrical
Smartlock Immobiliser (EF onwards)
What happens: Engine cranks but won’t start. An exclamation mark appears below the handbrake warning light on the dash. The fuel pump may prime (whine for 2 seconds) but the injectors won’t fire.
Why it happens: The Smartlock system prevents fuel delivery unless the key transponder matches the BEM. When the BEM, ECU, or key loses synchronisation, from a flat battery, engine swap, or ECU replacement, the car won’t start. This is confusing because the car cranks normally and may even fire briefly if starting fluid is sprayed into the intake.
How to fix it: An auto electrician or Ford dealer can reprogram the Smartlock. For modified or project cars, a Smartlock bypass module ($50-100) permanently disables the system. When swapping engines between models (e.g., EL motor into EF), use the original car’s ECU and BEM, don’t mix components from different vehicles unless you’re prepared to deal with Smartlock issues.
Severity: Urgent. The car will not start.
Alternator Output Issues
What happens: Battery light on dash, dim lights, accessories misbehaving, battery going flat overnight.
Why it happens: The alternator wears with age. Output should be 13.8-14.4V at idle. Some replacement alternators come with a different pulley size, which affects output at idle. The wiring between alternator and battery can also develop high resistance from corrosion.
How to fix it: Test charging output with a multimeter. Replace the alternator if output is below 13.5V at idle. Ensure the correct pulley size is fitted. Clean and tighten all battery and alternator cable connections. Apply dielectric grease. Cost: $150-300 for the alternator.
Severity: Needs attention. A failing charging system will eventually strand you.
Diagnostic Code Reading
What happens: The check engine light illuminates, but you need to read the fault codes.
Why it happens: Various sensor and system faults trigger stored codes.
How to fix it: EA-EL: You can read fault codes with a DIY test light. Short the far-left top and bottom pins on the diagnostic plug and count the flashes on the check engine light. AU: Requires an OBD-II scan tool or a Forscan Lite app on Android. Common codes: 636 (transmission oil temp), 634 (gear selector sensor), 786 (various sensor faults), P0748 (AU limp mode). Document all codes before clearing them.
Severity: Varies by code. Some are informational; others indicate urgent problems.
Suspension and Steering
Front Lower Control Arm Bushings
What happens: Clunking over bumps, vague steering, uneven tyre wear on inner edges.
Why it happens: The rubber bushings in the front lower control arms perish with age. Cars driven on rough rural roads wear faster.
How to fix it: Replace the control arms with new bushings. Complete arms are often cheaper than pressing new bushings. Polyurethane bushings are available for a firmer ride. Cost: $150-300 per side fitted.
Severity: Needs attention. Worn bushings compromise handling and braking.
AU Independent Rear Suspension (IRS) Bushing Wear
What happens: Clunking from the rear over bumps. Rear-end wander under braking. Uneven rear tyre wear.
Why it happens: The AU sedan’s independent rear suspension uses rubber trailing arm bushings that wear with age and load.
How to fix it: Replace the rear trailing arm bushings. This can be done without removing the subframe, but access is tight. Cost: $200-400 per side fitted.
Severity: Needs attention. Worn rear bushings affect handling stability, particularly under braking.
Power Steering Pump Failure (AU)
What happens: Heavy steering, whining noise from the power steering pump, fluid leaks.
Why it happens: The power steering pump wears with age. Low fluid from leaking hoses accelerates pump failure.
How to fix it: Replace the power steering pump. The same process applies to EF and EL models. Cost: $200-400 fitted. Replace the high-pressure hose if it’s seeping.
Severity: Needs attention. Low fluid or a failed pump makes the car difficult to steer at low speeds.
Body
Boot Floor and Spare Tyre Well Rust
What happens: Rust perforations in the boot floor, particularly around the spare tyre well. Water pooling in the boot.
Why it happens: Water enters through deteriorated taillight seals and sits in the spare tyre well. The trapped moisture rusts the metal from underneath.
How to fix it: Source a replacement boot floor from a wrecker (EA-ED sedan floors only fit EA-ED sedans; wagon floors are completely different). Alternatively, cut out rust and weld in repair panels. Replace taillight seals to prevent recurrence. Professional repair: $500-1,500.
Severity: Needs attention. Structural rust compromises the boot floor’s load-bearing capacity.
Door Bottom Rust
What happens: Rust visible at the bottom edge of the doors, starting as bubbles and progressing to holes.
Why it happens: Blocked drain holes in the door skins trap water. The water sits against the door skin and rusts from the inside out.
How to fix it: Clear blocked drain holes first. Treat surface rust with rust converter and touch-up paint. If perforated, replacement doors from a wrecker are the most cost-effective repair. Cost varies.
Severity: Minor annoyance initially, but progresses if ignored.
Preventive Maintenance
To avoid the worst problems, prioritise these tasks:
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Change engine oil every 7,500 km using 10W-40 mineral or 5W-30 semi-synthetic oil. Shorter intervals help prevent lifter tick by keeping oil passages clean.
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Replace the TFI module proactively (EA-ED) every 5 years or carry a spare at all times. This is a $100 part that will otherwise strand you.
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Service the automatic transmission every 40,000 km. Change fluid and filter. The BTR 4-speed needs regular care to survive.
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Inspect coolant hoses, heater tap, and thermostat annually. Replace rubber hoses every 10 years regardless of appearance.
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Clear door drain holes annually. Insert a piece of wire into each drain hole at the bottom of each door to prevent water accumulation.
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Keep all Smartlock keys together (EF onwards). If you lose all keys, reprogramming is expensive. Have spare keys programmed while the system is functional.
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Replace distributor cap and rotor every 40,000 km (EA-ED). Inspect spark plug leads for cracks and high resistance.
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