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

Faults Remedies
Defective Ignition Switch Check up for loose connection
Defective Solenoid Check the self-starter by giving direct current
Loose or dirty battery connection Clean and fix the connection properly
Hydraulic Lock in combustion chamber Remove 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 gear Demount the self-starter, clean the starter pinion and refit.

POOR STARTING OF THE ENGINE

Faults Remedies
Weak spark Check up and adjust air gap of spark plug and distributor
Loose connection in primary circuit Check up all connections for proper tightness
Defective Solenoid Replace with the new one
Restricted or defective fuel supply Check up working of fuel pump and carburetor
Restricted Air supply Clean air cleaner and check up choke valve position

SPARK MISSING IN ENGINE AT ALL SPEEDS

Faults Remedies
One or more spark plugs short Replace the defective plugs
Loose or dirty wiring connections Set them correctly
Presence of water in petrol Drain the petrol, remove water traces and refill petrol
Maladjustment of float ball level Set it correctly
Wrong Adjustment of Carburetor Adjust slow running perfectly
Tata Sumo Engine Overhauling Procedure

HIGH FUEL CONSUMPTION

Faults Remedies
Mis-adjustment of contact breaker points Adjust these properly
Defective spark plug Adjust the air gap properly or change the spark plug
Ignition timing set too advance or too retard Set the ignition correctly
Binding of brakes Adjust the brakes correctly
Clutch slipping Adjust clutch plate correctly

EXCESSIVE OIL CONSUMPTION

Faults Remedies
External leaks Change oil seals and Replace gaskets
Burning oil in the combustion chamber Check valve stem and piston ring clearance
Oil level too high Maintain oil at proper level
Poor viscosity of oil Use correct grade oil

ENGINE STOPS IMMEDIATELY AFTER START

Faults Remedies
Defective air gap of spark plug Set it correctly
Dirty spark plug Clean it and test properly
Dirty or misadjusted CB point Clean 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

Causes Remedies
Diluted or thin oil Change oil
Oil pump screen clogged Clean screen
Worn pump gear Overhaul pump
Main and big end bearings badly worn Replace bearings
Defective gaskets Replace gasket
Weak relief valve spring Change the spring
Leak in the system Trace and rectify
Engine over heating Trace and rectify
Pressure gauge unserviceable Rectify

HIGH ENGINE OIL PRESSURE

Causes Remedies
Oil too thick (wrong grade) Fill correct grade
Choked passage to relief valve Rectify
Relief valve set too high Set Correctly
Pressure gauge over-reading Test with Master Gauge
Components, Operation and Layout of Automobile Steering System

OIL MIXING WITH WATER

Causes Remedies
Oil cooler tubes punctured Replace the tube assembly
Cylinder head gasket cracked Replace the gasket
Cylinder head or block cracked Repair 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.

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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