FIAT Uno 45 - Manual (Page 294)

Engine cuts out suddenly –
ignition fault
Ⅵ Ⅵ Loose or disconnected LT wires
Ⅵ Ⅵ Wet HT leads or distributor cap (after
traversing water splash)
Ⅵ Ⅵ Coil failure (check for spark)
Ⅵ Ⅵ Other ignition fault (see Chapter 4)
Engine misfires before cutting out
– fuel fault
Ⅵ Ⅵ Fuel tank empty
Ⅵ Ⅵ Fuel pump defective or filter blocked
(check for delivery)
Ⅵ Ⅵ Fuel tank filler vent blocked (suction will be
evident on releasing cap)
Ⅵ Ⅵ Carburettor needle valve sticking
Ⅵ Ⅵ Carburettor jets blocked (fuel contami-
nated)
Ⅵ Ⅵ Other fuel system fault (see Chapter 3)
Engine cuts out – other causes
Ⅵ Ⅵ Serious overheating
Ⅵ Ⅵ Major mechanical failure (eg camshaft
drive)
Ignition (no-charge) warning light
illuminated
Ⅵ Ⅵ Slack or broken drivebelt — retension or
renew (Chapter 9)
Ignition warning light not
illuminated
Ⅵ Ⅵ Coolant loss due to internal or external
leakage (see Chapter 2)
Ⅵ Ⅵ Thermostat defective
Ⅵ Ⅵ Low oil level
Ⅵ Ⅵ Brakes binding
Ⅵ Ⅵ Radiator clogged externally or internally
Ⅵ Ⅵ Electric cooling fan not operating correctly
Ⅵ Ⅵ Engine waterways clogged
Ⅵ Ⅵ Ignition timing incorrect or automatic
advance malfunctioning
Ⅵ Ⅵ Mixture too weak
Note: Do not add cold water to an overheated
engine or damage may result
Note: Low oil pressure in a high-mileage
engine at tickover is not necessarily a cause
for concern. Sudden pressure loss at speed is
far more significant. In any event check the
gauge or warning light sender before
condemning the engine.
Gauge reads low or warning light
illuminated with engine running
Ⅵ Ⅵ Oil level low or incorrect grade
Ⅵ Ⅵ Defective gauge or sender unit
Ⅵ Ⅵ Wire to sender unit earthed
Ⅵ Ⅵ Engine overheating
Ⅵ Ⅵ Oil filter clogged or bypass valve defective
Ⅵ Ⅵ Oil pressure relief valve defective
Ⅵ Ⅵ Oil pick-up strainer clogged
Ⅵ Ⅵ Oil pump worn or mountings loose
Ⅵ Ⅵ Worn main or big-end bearings
Pre-ignition (pinking) on
acceleration
Ⅵ Ⅵ Incorrect grade of fuel
Ⅵ Ⅵ Ignition timing incorrect
Ⅵ Ⅵ Distributor faulty or worn
Ⅵ Ⅵ Worn or maladjusted carburettor
Ⅵ Ⅵ
Excessive carbon build-up in engine
Whistling or wheezing noises
Ⅵ Ⅵ Leaking vacuum hose
Ⅵ Ⅵ Leaking carburettor or manifold gasket
Ⅵ Ⅵ Blowing head gasket
Tapping or rattling
Ⅵ Ⅵ Incorrect valve clearances (where appli-
cable)
Ⅵ Ⅵ Worn valve gear
Ⅵ Ⅵ Worn timing chain or belt
Ⅵ Ⅵ Broken piston ring (ticking noise)
Knocking or thumping
Ⅵ Ⅵ Unintentional mechanical contact (eg fan
blades)
Ⅵ Ⅵ Worn drivebelt
Ⅵ Ⅵ Peripheral component fault (generator,
water pump, etc)
Ⅵ Ⅵ Worn big-end bearings (regular heavy
knocking, perhaps less under load)
Ⅵ Ⅵ Worn main bearings (rumbling and
knocking, perhaps worsening under load)
Ⅵ Ⅵ Piston slap (most noticeable when cold)
Engine noises
Low engine oil pressure
Engine overheats Engine cuts out and will not restart
Fault Finding
REF•11
REF
Crank engine and check for spark. Note
use of insulated tool