Via Veloce by Wille R. www.veloce.se Internet since November 1995 and still here.
Alfa Romeo fault diagnosis. Some common symptoms and perhaps some reasons.
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Cooling system overheating
- Insufficient coolant in system
- Pump ineffective due to slack drivebelt
- Radiator blocked either internally or externally
- Kinked or collapsed hose causing coolant flow restriction
- Thermostat not working properly
- Engine out of tune
- Ignition timing retarded or auto advance malfunction
- Cylinder head gasket blown
- Cylinder head gasket blown
- Exhaust system partially blocked
- Engine oil level too low
- Brakes binding
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Engine running too cool
- Faulty thermostat
- Incorrect or missing thermostat
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Loss of coolant
- Loose hose clips
- Hoses perished or leaking
- Radiator leaking
- Radiator leaking
- Blown cylinder head gasket
- Cracked cylinder block or head
- Leaking from heater control
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Heater gives insufficient output
- Engine overcooled (see above)
- Heater matrix blocked
- Heater controls maladjusted or broken
- Heater control valve jammed or otherwise defective
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Fuel system - Fuel smell
- Smell of petrol when engine is stopped
- Leaking fuel lines or unions
- Leaking fuel tank
- White smoke from exhaust, check the brake fluid. Booster could be leaking
- Blue or black smoke from exhaust. Worn piston rings or valve guides let engine oil pass by
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Smell of petrol when engine is idling
- Leaking fuel line unions between pump and carburettor
- Overflow of fuel from float chamber due to wrong level setting,
- ineffective needle valve or punctured float
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Excessive fuel consumption for reasons not covered by
leaks or float chamber faults
- Worn jets
- Over-rich setting
- Sticking mechanism
- Dirty air cleaner element
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Difficult starting, uneven running, lack of power,
cutting out
- One or more jets blocked or restricted
- Float chamber fuel level too low or needle valve sticking
- Float chamber fuel} level too low or needle valve
- Fuel pump not delivering
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Difficult starting when cold
- Choke control
- Insufficient use of manual choke
- Weak mixture
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Difficult starting when hot
- Excessive use of manual choke
- Accelerator pedal pumped before starting
- Vapour lock especially in hot weather or at high altitude)
- Rich mixture
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Engine does not respond properly to throttle
- Faulty accelerator pump
- Blocked jets
- Slack in accelerator cable
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Engine idle sped drops when hot
- Incorrect air cleaner intake setting
- Overheated fuel pump
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Engine runs on
- Idle speed too high
- Too rich mixture
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Ignition system - Mechanical breaker system Engine fails to start
- Loose battery connections
- Discharged battery
- Oil in contact points
- Disconnected ignition leads
- Faulty condenser
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Engine starts and runs but misfires
- Faulty spark plug
- Cracked distributor cap
- Cracked rotor arm
- Worn advance mechanism
- Incorrect spark plug gap
- Incorrect contact points gap
- Faulty condenser
- Faulty coil
- Incorrect timing
- Poor engine / transmission earth connections
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Engine overheats, lacks power
- Seized distributor weights
- Perforated vacuum pipe
- Incorrect ignition timing
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Eectronic type - Engine fails to start
- Excessive gap on TDC sensor
- TDC or engine speed sensor short circuited or earthed
- Defective ignition control unit
- Control unit multiplug contacts corroded
- Defective coil
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Engine lacks power, high fuel consumption
- Incorrect ignition advance
- TDC sensor incorrectly set
- Distributor vacuum hose blocked
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Clutch - transmission Difficulty
in engaging gear (grinding)
- Clutch cable adjustment incorrect
- See under Clutch spin
- Judder when taking up drive
- Engine / transmission mountings loose or worn
- Driven plate linings contaminated or worn
- Pressure plate loose or defective
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Clutch spin (failure to disengage) so that gears cannot
be meshed
- Incorrect release bearing to pressure plate clearance on splines (may occur after vehicle standing idle for long periods)
- Damaged or misalign pressure plate assembly stretched or broken
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Clutch slip, increase in engine but speed does
not increase, road speed
- Incorrect cable adjustment
- Driven plate linings worn or contaminated
- Pressure plate defective
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Noise evident when clutch pedal depressed
- Release arm pivots unlubricated
- Release bearing worn, loose or unlubricated
- Worn or damaged pressure plate
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Noise evident as clutch pedal released
- Distorted driven plate
- Broken or weak driven plate cushion coil springs
- Incorrect pedal adjustment
- Weak or broken clutch pedal return spring
- Distorted or worn input shaft
- Release bearing loose on retainer hub
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Weak or ineffective synchromesh
- Synchro bulk rings worn, split or damaged
- Synchromesh units worn, or damaged
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Jumps out of gear
- Gearchange mechanism worn
- Synchromesh units badly worn
- Selector fork badly worn
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Excessive noise in transmission
- Incorrect grade of oil in gearbox or oil level too low
- Gearteeth excessively worn or damaged
- Intermediate gear thrust washers worn allowing excessive end play
- Worn bearings
- Worn universal joint, tickling noise when driving off
- Heavy knocking when driving off is often the propeller shaft support bearing
- Ticking noise when driving off is often universal joint at rear axle.
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Difficulty in engaging gears
- Clutch pedal adjustment incorrect
- Hydralic fluid level too low
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Noise when cornering
- Wheel bearing or driveshaft fault
- Differential fault
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Braking system Excessive pedal travel
- Pads or shoes excessively worn
- Incorrect pedal or servo pushrod adjustment
- Automatic adjusters faulty
- Seized wheel cylinder or calliper piston
- Master cylinder seals worn
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Pedal feels spongy or soggy
- Air in hydraulic system
- Low fluid level
- Loose connections
- Flexible hose perished
- Defective wheel cylinder or calliper seal
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Pedal feels springy
- New pads or linings not bedded-in
- Master cylinder mounting loose
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Excessive effort required to stop car
- Worn or contaminated linings or pads
- Incorrect grade of lining or pad material
- Servo vacum hose leaking or disconnected
- Faulty servo or non-return valve
- Seized calliper or wheel cylinder piston
- I.e. circuit defective on dual circuit hydraulic system
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Brakes pull to one side
- Friction linings contaminated on one side of car
- Seized hydraulic piston on one side of car
- Different types of linings fitted on different sides of car, or new linings on one side only
- Seized automatic adjuster on one side of car
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Pedal vibrates when brakes applied
- Discs or drums distorted
- Friction linings excessively worn
- Loose backplate or calliper mounting bolts
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Brakes squeal
- Disks rusty or damp, often temporary fault with no action needed.
- Dust or grit in brake drums
- Linings excessively worn
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Loosing Brake fluid
- Worn servo/booster seals and gaskets.
- Worn air control valve
- Worn seals in brake master cylinder. Shown by leaks from the MC
- Leaking from junction
