Guide to Fault Detection and Rectification System in Automobile

This aspect plays a very important role in day to day working of a technician. It becomes so mandatory to diagnose a fault before we proceed for its rectification. A qualified technician proceeds systematically with a lot of patient in order to detect the fault. We must adopt all our technical skill and talent so that the faults can be rectified within a stipulated time within the available resources and time.

ENGINE NOT CRANKING WITH SELF STARTER

FaultsRemedies
Defective Ignition SwitchCheck up for loose connection
Defective SolenoidCheck the self-starter by giving direct current
Loose or dirty battery connectionClean and fix the connection properly
Hydraulic Lock in combustion chamberRemove the spark plug crank the engine and observe the engine oil or water comes out from the spark plug hole if so change the cylinder head gasket
Jamming of self-starter pinion with ring gearDemount the self-starter, clean the starter pinion and refit.

POOR STARTING OF THE ENGINE

FaultsRemedies
Weak sparkCheck up and adjust air gap of spark plug and distributor
Loose connection in primary circuitCheck up all connections for proper tightness
Defective SolenoidReplace with the new one
Restricted or defective fuel supplyCheck up working of fuel pump and carburetor
Restricted Air supplyClean air cleaner and check up choke valve position

SPARK MISSING IN ENGINE AT ALL SPEEDS

FaultsRemedies
One or more spark plugs shortReplace the defective plugs
Loose or dirty wiring connectionsSet them correctly
Presence of water in petrolDrain the petrol, remove water traces and refill petrol
Maladjustment of float ball levelSet it correctly
Wrong Adjustment of CarburetorAdjust slow running perfectly

HIGH FUEL CONSUMPTION

FaultsRemedies
Mis-adjustment of contact breaker pointsAdjust these properly
Defective spark plugAdjust the air gap properly or change the spark plug
Ignition timing set too advance or too retardSet the ignition correctly
Binding of brakesAdjust the brakes correctly
Clutch slippingAdjust clutch plate correctly

EXCESSIVE OIL CONSUMPTION

FaultsRemedies
External leaksChange oil seals and Replace gaskets
Burning oil in the combustion chamberCheck valve stem and piston ring clearance
Oil level too highMaintain oil at proper level
Poor viscosity of oilUse correct grade oil

ENGINE STOPS IMMEDIATELY AFTER START

FaultsRemedies
Defective air gap of spark plugSet it correctly
Dirty spark plugClean it and test properly
Dirty or misadjusted CB pointClean and adjust

ENGINE OVER HEATING

(a) Loose or broken fan belt.

(b) Leaks in cooling system.

(c) Restricted water passage.

(d) Dirty Coolant.

(e) Radiator air passages blocked.

(f) Defective water pump or impeller.

(g) Defective thermostat

LOW OIL PRESSURE

CausesRemedies
Diluted or thin oilChange oil
Oil pump screen cloggedClean screen
Worn pump gearOverhaul pump
Main and big end bearings badly wornReplace bearings
Defective gasketsReplace gasket
Weak relief valve springChange the spring
Leak in the systemTrace and rectify
Engine over heatingTrace and rectify
Pressure gauge unserviceableRectify

HIGH ENGINE OIL PRESSURE

CausesRemedies
Oil too thick (wrong grade)Fill correct grade
Choked passage to relief valveRectify
Relief valve set too highSet Correctly
Pressure gauge over-readingTest with Master Gauge

OIL MIXING WITH WATER

CausesRemedies
Oil cooler tubes puncturedReplace the tube assembly
Cylinder head gasket crackedReplace the gasket
Cylinder head or block crackedRepair or Replace

ROAD TEST OF THE VEHICLE

The vehicles should be road tested after over hauling. First start the vehicle and observe the engine sound, any leak (oil, fuel and water) and all the gauges with safety warning provided on instrument panel. If gauges read satisfactory then go for road test. After setting the vehicle in motion first check the foot and hand brake serviceability, then run the vehicle in different gears and apply the brakes as and when required. At the end of the road test again check the wheel drum of the vehicle for overheating and any leak from the engine.

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Author: Aliva Tripathy

Taking out time from a housewife life and contributing to AxiBook is a passion for me. I love doing this and gets mind filled with huge satisfaction with thoughtful feedbacks from you all. Do love caring for others and love sharing knowledge more than this.

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