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Home   Via Veloce by Wille R.  www.veloce.se     On the Internet since November 1995 and still here.

dotWebers & carbs dotOil dotBrakes   dotElectrical system
Next First published 5 September 2001

Alfa Romeo fault diagnosis. Some common symptoms and perhaps some reasons. Thanks to Highwood Motor Co. There are a lot of clues for DIY at Via veloce. If you have any comments or suggestions or have an other idea about the content, please tell us, thank you.


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Engine fails to turn when starter operated
Starter motor turns engine slowly but fails to start
Starter motor spins without turning engine
Engine turns normally but fails to start
Engine fires but will not run
Engine cuts out and will not restart

Engine misfires before cutting out - fuel fault

Engine cuts out - other causes
Engine overheats
Low engine oil pressure


Engine noises
Whistling or wheezing noises
Tapping or rattling

Knocking or thumping

Engine fires but will not run

Difficult starting when cold

Difficult starting when hot

Engine slow to warm up

Engine idles roughly

Engine lacks power

Engine misfires throughout speed range

Poor engine braking

Pre-ignition (pinking) during acceleration

Engine runs on after switching off


Low oil pressure (verify accuracy of sender before dismantling)
Excessive oil consumption 
Oil contaminated with water
Oil contaminated with fuel
Oil smoke
Unusual mechanical noises 


Cooling system overheating
Engine running too cool
Loss of coolant
Heater gives insufficient output
Fu1iel system - Fuel smell
Smel1 of petrol when engine is idling
Excessive fuel consumption for reasons not covered by leaks or float chamber faults


Difficult starting, uneven running, lack of power, cutting out
Difficult starting when cold
Difficult starting when hot
Engine does not respond properly to throttle
Engine idle sped drops when hot
Engine runs on


Ignition system - Mechanical breaker system
Engine fails to start
Engine starts and runs but misfires
Engine overheats, lacks power
Electronic type - Engine fails to start


Clutch - transmission
Difficulty in engaging gear (grinding)
Clutch spin (failure to disengage) so that gears cannot be meshed
Clutch slip, increase in engine but speed does not increase, road speed
Noise evident when clutch pedal depressed
Noise evident as clutch pedal released
Weak or ineffective synchromesh
Jumps out of gear
Excessive noise in transmission
Difficulty in engaging gears
Noise when cornering


Braking system
Excessive pedal travel
Pedal feels spongy or soggy
Pedal feels springy
Excessive effort required to stop car
Brakes pull to one side
Pedal vibrates when brakes applied
Brakes squeal


Top Cooling system overheating   

  1. Insufficient coolant in system
  2. Pump ineffective due to slack drivebelt
  3. Radiator blocked either internally or externally
  4. Kinked or collapsed hose causing coolant flow restriction
  5. Thermostat not working properly
  6. Engine out of tune
  7. Ignition timing retarded or auto advance malfunction
  8. Cylinder head gasket blown
  9. Cylinder head gasket blown
  10. Exhaust system partially blocked
  11. Engine oil level too low
  12. Brakes binding

Top Engine running too cool

  1. Faulty thermostat
  2. Incorrect or missing thermostat

Top Loss of coolant

  1. Loose hose clips
  2. loses perished or leaking
  3. Radiator leaking
  4. Radiator leaking
  5. Blown cylinder head gasket
  6. Cracked cylinder block or head

Top Heater gives insufficient output

  1. Engine overcooled (see above)
  2. Heater matrix blocked
  3. Heater controls maladjusted or broken
  4. Heater control valve jammed or otherwise defective

Top Fuel system - Fuel smell

  1. Smell of petrol when engine is stopped
  2. Leaking fuel lines or unions
  3. Leaking fuel tank

Top Smell of petrol when engine is idling

  1. Leaking fuel line unions between pump and carburettor
  2. Overflow of fuel from float chamber due to wrong level setting,
  3. ineffective needle valve or punctured float

Top Excessive fuel consumption for reasons not covered by leaks or float chamber faults

  1. Worn jets
  2. Over-rich setting
  3. Sticking mechanism
  4. Dirty air cleaner element

Top Difficult starting, uneven running, lack of power, cutting out

  1. One or more jets blocked or restricted
  2. Float chamber fuel level too low or needle valve sticking
  3. Float chamber fuel} level too low or needle valve
  4. Fuel pump not delivering

Top Difficult starting when cold

  1. Choke control
  2. Insufficient use of manual choke
  3. Weak mixture

Top Difficult starting when hot

  1. Excessive use of manual choke
  2. Accelerator pedal pumped before starting
  3. Vapour lock especially in hot weather or at high altitude)
  4. Rich mixture

Top Engine does not respond properly to throttle

  1. Faulty accelerator pump
  2. Blocked jets
  3. Slack in accelerator cable

Top Engine idle sped drops when hot

  1. Incorrect air cleaner intake setting
  2. Overheated fuel pump

Top Engine runs on

  1. Idle speed too high
  2. Too rich mixture

Top Ignition system - Mechanical breaker system  Engine fails to start

  1. Loose battery connections
  2. Discharged battery
  3. Oil in contact points
  4. Disconnected ignition leads
  5. Faulty condenser

Top Engine starts and runs but misfires

  1. Faulty spark plug
  2. Cracked distributor cap
  3. Cracked rotor arm
  4. Worn advance mechanism
  5. Incorrect spark plug gap
  6. Incorrect contact points gap
  7. Faulty condenser
  8. Faulty coil
  9. Incorrect timing
  10. Poor engine / transmission earth connections

Top Engine overheats, lacks power

  1. Seized distributor weights
  2. Perforated vacuum pipe
  3. Incorrect ignition timing

Top Eectronic type - Engine fails to start

  1. Excessive gap on TDC sensor
  2. TDC or engine speed sensor short circuited or earthed
  3. Defective ignition control unit
  4. Control unit multiplug contacts corroded
  5. Defective coil

Top Engine lacks power, high fuel consumption

  1. Incorrect ignition advance
  2. TDC sensor incorrectly set
  3. Distributor vacuum hose blocked

Top Clutch - transmission   Difficulty in engaging gear (grinding)

  1. Clutch cable adjustment incorrect
  2. See under Clutch spin
  3. Judder when taking up drive
  4. Engine / transmission mountings loose or worn
  5. Driven plate linings contaminated or worn
  6. Pressure plate loose or defective

Top Clutch spin (failure to disengage) so that gears cannot be meshed

  1. Incorrect release bearing to pressure plate clearance on splines (may occur after vehicle standing idle for long periods)
  2. Damaged or misalign pressure plate assembly stretched or broken

Top Clutch slip, increase in engine but speed does not increase, road speed

  1. Incorrect cable adjustment
  2. Driven plate linings worn or contaminated
  3. Pressure plate defective

Top Noise evident when clutch pedal depressed

  1. Release arm pivots unlubricated
  2. Release bearing worn, loose or unlubricated
  3. Worn or damaged pressure plate

Top Noise evident as clutch pedal released

  1. Distorted driven plate
  2. Broken or weak driven plate cushion coil springs
  3. Incorrect pedal adjustment
  4. Weak or broken clutch pedal return spring
  5. Distorted or worn input shaft
  6. Release bearing loose on retainer hub

Top Weak or ineffective synchromesh

  1. Synchro bulk rings worn, split or damaged
  2. Synchromesh units worn, or damaged

Top Jumps out of gear

  1. Gearchange mechanism worn
  2. Synchromesh units badly worn
  3. Selector fork badly worn

Top Excessive noise in transmission

  1. Incorrect grade of oil in gearbox or oil level too low
  2. Gearteeth excessively worn or damaged
  3. Intermediate gear thrust washers worn allowing excessive end play
  4. Worn bearings
  5. Worn universal joint, tickling noise when driving off
  6. Heavy knocking when driving off is often the propeller shaft support bearing
  7. Ticking noise when driving off is often universal joint at rear axle.

Top Difficulty in engaging gears

  1. Clutch pedal adjustment incorrect
  2. Hydralic fluid level too low

Top Noise when cornering

  1. Wheel bearing or driveshaft fault
  2. Differential fault

Top Braking system  Excessive pedal travel

  1. Pads or shoes excessively worn
  2. Incorrect pedal or servo pushrod adjustment
  3. Automatic adjusters faulty
  4. Seized wheel cylinder or calliper piston
  5. Master cylinder seals worn

Top Pedal feels spongy or soggy

  1. Air in hydraulic system
  2. Low fluid level
  3. Loose connections
  4. Flexible hose perished
  5. Defective wheel cylinder or calliper seal

Top Pedal feels springy

  1. New pads or linings not bedded-in
  2. Master cylinder mounting loose

Top Excessive effort required to stop car

  1. Worn or contaminated linings or pads
  2. Incorrect grade of lining or pad material
  3. Servo vacum hose leaking or disconnected
  4. Faulty servo or non-return valve
  5. Seized calliper or wheel cylinder piston
  6. I.e. circuit defective on dual circuit hydraulic system

Top Brakes pull to one side

  1. Friction linings contaminated on one side of car
  2. Seized hydraulic piston on one side of car
  3. Different types of linings fitted on different sides of car, or new linings on one side only
  4. Seized automatic adjuster on one side of car

Top Pedal vibrates when brakes applied

  1. Discs or drums distorted
  2. Friction linings excessively worn
  3. Loose backplate or calliper mounting bolts

Top Brakes squeal

  1. Disks rusty or damp, often temporary fault with no action needed.
  2. Dust or grit in brake drums
  3. Linings excessively worn

 

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