Get Engine Diagnosis Guide for Suzuki Alto 4 Door Fifth Generation (1998-2003)

ENGINE DIAGNOSIS 6-1

SECTION 6

ENGINE DIAGNOSIS

CONTENTS

GENERAL INFORMATION 6- 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ENGINE DIAGNOSIS 6- 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

On-Board Diagnostic System 6- 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Precaution in Diagnosing Troubles 6- 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Engine Diagnostic Flow Table 6- 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Engine Diagnosis Table 6-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GENERAL INFORMATION

STATEMENT ON CLEANLINESS AND CARE

An automobile engine is a combination of many machined, honed, polished and lapped surfaces with tolerances

that are measured in the thousands of an millimeter (ten thousands of inch). Accordingly, when any internal engine

parts are serviced, care and cleanliness are important. Throughout this section, it should be understood that proper

cleaning and protection of machined surfaces and friction areas is part of the repair procedure. This is considered

standard shop practice even if not specifically stated.

D A liberal coating of engine oil should be applied to friction areas during assembly to protect and lubricate the

surfaces on initial operation.

D Whenever valve train components, pistons, piston rings, connecting rods, rod bearings, and crankshaft journal

bearings are removed for service, they should be retained in order. At the time of installation, they should be

installed in the same locations and with the same mating surfaces as when removed.

D Battery cables should be disconnected before any major work is performed on the engine. Failure to disconnect

cables may result in damage to wire harness or other electrical parts.

D Throughout this manual, the four cylinders of the engine are

identified by numbers: No.1, No.2, and No.3 as counted from

crankshaft pulley side to flywheel side.

1. No.1 cylinder

2. No.2 cylinder

3. No.3 cylinder

GENERAL INFORMATION ON ENGINE

SERVICE

THE FOLLOWING INFORMATION ON ENGINE SERVICE

SHOULD BE NOTED CAREFULLY, AS IT IS IMPORTANT IN

PREVENTING DAMAGE, AND IN CONTRIBUTING TO RELI-

ABLE ENGINE PERFORMANCE.

D When raising or supporting engine for any reason, do not use a

jack under oil pan. Due to small clearance between oil pan and

oil pump strainer, jacking against oil pan may cause it to be bent

against strainer resulting in damaged oil pick-up unit.

D It should be kept in mind, while working on engine, that 12-volt

electrical system is capable of violent and damaging short cir-

cuits.

When performing any work where electrical terminals could

possibly be grounded, ground cable of the battery should be dis-

connected at battery.

D Any time the air cleaner, air intake hose, throttle body or intake

manifold is removed, the intake opening should be covered. This

will protect against accidental entrance of foreign material which

could follow intake passage into cylinder and cause extensive

damage when engine is started.

D When disconnecting couplers, don’t pull wire harness but make

sure to hold coupler itself. With lock type coupler, be sure to un-

lock before disconnection. Attempt to disconnect coupler with-

out unlocking may result in damage to coupler. When

connecting lock type coupler, insert it till clicking sound is heard

and connect it securely.

6-2 ENGINE DIAGNOSIS

PRECAUTION ON FUEL SYSTEM SERVICE

D Work must be done with no smoking, in a well-ventilated area

and away from any open flames.

D As fuel feed line (between fuel pump and fuel pressure regula-

tor) is still under high fuel pressure even after engine was

stopped, loosening or disconnecting fuel feed line directly may

cause dangerous spout of fuel to occur where loosened or dis-

connected.

Before loosening or disconnecting fuel feed line, make sure to

release fuel pressure according to FUEL PRESSURE RELIEF

PROCEDURE.

A small amount of fuel may be released after the fuel line is dis-

connected.

In order to reduce the chance of personal injury, cover the fitting

to be disconnected with a shop cloth. Put that cloth in an ap-

proved container when disconnection is completed.

D Never run engine with fuel pump relay disconnected when en-

gine and exhaust system are hot.

D Fuel or fuel vapor hose connection varies with each type of pipe.

When reconnecting fuel or fuel vapor hose, be sure to connect

and clamp each hose correctly referring to left figure.

After connecting, make sure that the hose has no twist or kink.

D When installing fuel union bolt gasket, always use new gasket

and tighten union bolt to specified torque. See Section 6C for

specified torque.

D When installing injector, fuel feed pipe or fuel pressure regulator,

lubricate its O-ring with gasoline.

D When connecting fuel pipe flare nut, first tighten flare nut by

hand and then tighten it to specified torque.

ENGINE DIAGNOSIS 6-3

FUEL PRESSURE RELIEF PROCEDURE

After making sure that engine is cold, relief fuel pressure as follows.

1) Place transmission gear shift lever in “Neutral”, set parking

brake, and block drive wheels.

2) Remove fuel pump relay (1) from connector.

3) Remove fuel filler cap to release fuel vapor pressure in fuel tank

and then reinstall it.

4) Start engine and run it till it stops for lack of fuel. Repeat crank-

ing engine 2 – 3 times of about 3 seconds each time to dissipate

fuel pressure in lines. Fuel connections are now safe for servic-

ing.

5) Upon completion of servicing, install fuel pump relay to relay

box.

CAUTION:

This work must not be done when engine is hot. If done

so, it may cause adverse effect to catalyst.

FUEL LEAKAGE CHECK PROCEDURE

After performing any service on fuel system, check to make sure

that there are no fuel leakages as follows.

1) Turn the ignition switch ON position for 3 seconds (to operate

fuel pump) and then turn it OFF position.

Repeat this (ON and OFF) 3 or 4 times and apply fuel pressure

to fuel line (till fuel pressure is felt by hand placed on fuel return

hose).

2) In this state, check to see that there are no fuel leakages from

any part of fuel system.

6-4 ENGINE DIAGNOSIS

ON-BOARD DIAGNOSTIC SYSTEM

Refer to “On-Board Diagnostic System” in Section 6E1.

PRECAUTION IN DIAGNOSING TROUBLES

Be sure to read “Precaution in Diagnosing Troubles” in Section 6E1

and observe what is written there.

ENGINE DIAGNOSIS 6-5

ENGINE DIAGNOSIS

This vehicle is equipped with an engine and emission control system, which controls the A/F mixture, ignition tim-

ing, emission, etc. suitably to engine conditions by ECM. ECM has an On-Board Diagnostic system which detects

a malfunction in this system.

When diagnosing a trouble in the engine including this system, be sure to have understanding of the outline of “On-

Board Diagnostic system” and each item in “Precaution in Diagnosing Trouble” and follow “ENGINE DIAGNOSTIC

FLOW TABLE” given below to obtain correct result smoothly.

6-6 ENGINE DIAGNOSIS

ENGINE DIAGNOSTIC FLOW TABLE

Refer to the following pages for the details of each step.

STEP

ACTION YES NO

1 Customer Complaint Analysis

1) Perform customer complaint analysis.

Was customer complaint analysis performed?

Go to Step 2. Perform customer

complaint analysis.

2 Diagnostic Trouble Code (DTC) Check, Record and

Clearance

1) Check for DTC referring to “DTC Check” in

Section 6E1.

Is there any malfunction DTC(s)?

1) Print DTC or

write it down and

clear it by refer-

ring to “DTC

Clearance” in

section 6E1.

2) Go to Step 3.

Go to Step 4.

3 Visual Inspection

1) Perform visual inspection referring to the “Visual

Inspection” in this section.

Is there any faulty condition?

1) Repair or replace

malfunction part.

2) Go to Step 11.

Go to Step 5.

4 Visual Inspection

1) Perform visual inspection referring to the “Visual

Inspection” in this section.

Is there any faulty condition?

Go to Step 8.

5 Trouble Symptom Confirmation

1) Confirm trouble symptom referring to the “Trouble-

Symptom Confirmation” in this section.

Is trouble symptom identified?

Go to Step 6. Go to Step 7.

6 Rechecking and Record of DTC

1) Recheck for DTC referring to “DTC Check” in

Section 6E1.

Is there any DTC(s)?

Go to Step 9.

Go to Step 8.

7 Rechecking and Record of DTC

1) Recheck for DTC referring to “DTC Check” in

Section 6E1.

Is there any malfunction DTC(s)?

Go to Step 10.

8 Engine Basic Inspection and Engine Diagnosis Table

1) Check and repair according to “Engine Basic Check”

and “Engine Diagnosis Table” in this section.

Are check and repair complete?

Go to Step 11. 1) Check and repair

malfunction

part(s).

2) Go to Step 11.

9 Trouble shooting for DTC

1) Check and repair according to applicable DTC diag.

flow table in Section 6E1.

Are check and repair complete?

10 Check for Intermittent Problems

1) Check for intermittent problems referring to “Check for

Intermittent Problem” in this section.

Is there any faulty condition?

1) Repair or replace

malfunction

part(s).

2) Go to Step 11.

Go to Step 11.

11 Final Confirmation Test

1) Clear DTC if any.

2) Perform final confirmation test referring to “Final

Confirmation Test” in this section.

Is there any problem symptom, malfunction DTC or abnor-

mal condition?

Go to Step 6. End.

ENGINE DIAGNOSIS 6-7

1. CUSTOMER COMPLAINT ANALYSIS

Record details of the problem (failure, complaint) and how it occurred as described by the customer. For this

purpose, use of such an inspection form will facilitate collecting information to the point required for proper anal-

ysis and diagnosis.

CUSTOMER PROBLEM INSPECTION FORM (EXAMPLE)

User name: Model: VIN:

Date of issue: Date of Reg.: Date of problem: Mileage:

PROBLEM SYMPTOMS

j Difficult Starting

j No cranking

j No initial combustion

j No combustion

j Poor starting at

(j cold j warm j always)

j Other

j Poor Driveability

j Hesitation on acceleration

j Back fire/j After fire

j Lack of power

j Surging

j Abnormal knocking

j Other

j Poor idling

j Poor fast idle

j Abnormal idling speed

(j High j Low) ( r / min.)

j Unstable

j Hunting ( r/min. to r/min.)

j Other

j Engine Stall when

j Immediately after start

j Axal. pedal is depressed

j Accel. pedal is released

j Load is applied

j A/C j Electric load j P/S

j Other

j OTHERS:

VEHICLE/ENVIRONMENTAL CONDITION WHEN PROBLEM OCCURS

Environmental Condition

Weather

Temperature

Frequency

Road

j Fair j Cloudy j Rain j Snow j Always j Other

j Hot j Warm j Cool j Cold ( _F/ _C) j Always

j Always j Sometimes ( times/ day, month) j Only once j Under certain condition

j Urban j Suburb j Highway j Mountainous (j Uphill j Downhill) j Tarmacadam

j Gravel j Other

Vehicle Condition

Engine

Condition

j Cold j Warming up phase j Warmed up j Always j Other at starting

j Immediately after start j Racing without load j Engine speed ( r / min)

Vehicle

condition

j During driving: j Constant speed j Accelerating j Decelerating

j Right hand corner j left hand corner j When shifting (Lever position ) j At stop

j Vehicle speed when problem occurs ( km/h, Mile/h) j Other

Malfunction indicator

lamp condition

j Always ON j Sometimes ON j Always OFF j Good condition

Diagnostic trouble

First check: j No code j Normal code j Malfunction code ( )

code

Second check: j No code j Normal code j Malfunction code ( )

NOTE:

The above form is a standard sample. It should be modified according to conditions characteristic of each

market.

Operation

6-8 ENGINE DIAGNOSIS

2. DIAGNOSTIC TROUBLE CODE (DTC) CHECK, RECORD AND CLEARANCE

First, check DTC referring to “DTC Check” in Section 6E1. If DTC is indicated, print it or write it down and then

clear it by referring to “DTC Clearance” in Section 6E1. DTC indicates malfunction that occurred in the system

but does not indicate whether it exists now or it occurred in the past and the normal condition has been restored

now. To check which case applies, check the symptom in question according to Step 5 and recheck DTC accord-

ing to Step 6 or 7.

Attempt to diagnose a trouble based on DTC in this step only or failure to clear the DTC in this step will lead

to incorrect diagnosis, trouble diagnosis of a normal circuit or difficulty in troubleshooting.

3. and 4. VISUAL INSPECTION

Be sure to perform visual check of the following items that support proper function of the engine.

INSPECTION ITEM

REFERRING SECTION

D Engine oil – – – – – level, leakage

D Engine coolant – – – – – level, leakage

D Fuel – – – – – level, leakage

D Air cleaner element – – – – – dirt, clogging

D Battery – – – – – fluid level, corrosion of terminal

D Water pump belt and / or cooling fan belt – – – – – tension, damage

D Throttle cable – – – – – play, installation

D Vacuum hoses of air intake system – – – – – disconnection, looseness,

deterioration, bend

D Connectors of electric wire harness – – – – – disconnection, friction

D Fuses – – – – – burning

D Parts – – – – – installation, bolt – – – – – looseness

D Parts – – – – – deformation

D Other parts that can be checked visually

Also check following items at engine start, if possible

D Malfunction indicator lamp

D Charge warning lamp

D Engine oil pressure warning lamp

D Engine coolant temp. meter

D Fuel lever meter

D Abnormal air being inhaled from air intake system

D Exhaust system – – – – – leakage of exhaust gas, noise

D Other parts that can be checked visually

Section 0B

Section 6E1

Section 8

Section 6E1

Section 6H

Section 8

ENGINE DIAGNOSIS 6-9

5. TROUBLE SYMPTOM CONFIRMATION

Based on information obtained in Step 1 customer complaint analysis and Step 2 DTC check, confirm trouble

symptoms. Also, reconfirm DTC according to “DTC Confirmation Procedure” in Section 6E1.

6. and 7. RECHECKING AND RECORD OF DTC

Refer to “DTC Check” in section 6E1 for checking procedure.

8. ENGINE BASIC INSPECTION AND ENGINE DIAGNOSIS TABLE

Perform basic engine check according to the “Engine Basic Inspection Flow Table” first. When the end of the

flow table has been reached, check the parts of the system suspected as a possible cause referring to ENGINE

DIAGNOSIS TABLE and based on symptoms appearing on the vehicle (symptoms obtained through steps of

customer complaint analysis, trouble symptom confirmation and/or basic engine check) and repair or replace

faulty parts, if any.

ENGINE BASIC INSPECTION FLOW TABLE

STEP

ACTION YES NO

1 Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE

DIAG. FLOW

TABLE”.

2 Check battery voltage.

Is it 11 V or more?

Go to Step 3. Charge or replace

battery.

3 Is engine cranked? Go to Step 4. Go to “DIAGNOSIS”

in section 6G.

4 Does engine start? Go to Step 5. Go to Step 7.

5 Check engine idle speed/IAC duty referring to “Idle

Speed/IAC Duty Inspection” in section 6E1.

Is check result as specified?

Go to Step 6. Go to “ENGINE

DIAGNOSIS TABLE”

in this section.

6 Check ignition timing referring to “Ignition Timing Inspec-

tion” in section 6F.

Is check result as specified?

Go to “ENGINE

DIAGNOSIS TABLE”

in this section.

Adjust ignition

timing.

7 Check fuel supply as follows:

1) Check to make sure that enough fuel is filled in fuel

tank.

2) Turn the ignition switch ON position for 3 seconds and

then turn it OFF position.

Repeat this a few times.

Is fuel return pressure (returning sounds) felt from fuel

return hose when the ignition switch is turned ON posi-

tion?

Go to Step 9. Go to Step 8.

8 Check fuel pump for operating.

1) Was fuel pump operating sound heard from fuel filler

for about 3 seconds after turning the ignition switch ON

position and stop?

Go to “Diag. Flow

Table B-3” in section

6E1.

Go to “Diag. Flow

Table B-1” in section

6E1.

9 Check ignition spark referring to “Ignition Spark Test”

in section 6F.

Is it in good condition?

Go to Step 10. Go to “DIAGNOSIS”

in section 6F.

10 Check fuel injector referring to “Fuel Injector Inspection” in

section 6E1.

Is it in good condition?

Go to “ENGINE

DIAGNOSIS TABLE”

in this section.

Go to “Diag. Flow

Table B-2 in section

6E1.

6-10 ENGINE DIAGNOSIS

9. TROUBLESHOOTING FOR DTC

Based on the DTC indicated in Step 6 or 7 and referring to the applicable DTC diag. flow table in Section 6E1,

locate the cause of the trouble, namely in a sensor, switch, wire harness, connector, actuator, ECM or other

part and repair or replace faulty parts.

10. CHECK FOR INTERMITTENT PROBLEM

Check parts where an intermittent trouble is easy to occur (e.g., wire harness, connector, etc.), referring to

“INTERMITTENT AND POOR CONNECTION” in Section 0A and related circuit of DTC recorded in step 2.

11. FINAL CONFIRMATION TEST

Confirm that the problem symptom has gone and the engine is free from any abnormal conditions. If what has

been repaired is related to the DTC, clear the DTC once, perform DTC confirmation procedure and confirm

that no malfunction DTC (a normal code) is indicated.

ENGINE DIAGNOSIS TABLE

Condition

Possible Cause Reference Item

Hard starting

(Engine cranks OK)

Engine and emission control system

out of order.

D Faulty CMP sensing rotor

D Faulty idle air control system

D Faulty ECT sensor or MAP sensor

D Faulty ECM

Low compression.

D Compression leak from valve seat

D Sticky valve stem

D Weak or damaged valve springs

D Compression leak at cylinder head gasket

D Sticking or damaged piston ring

D Worn piston, ring or cylinder

Others

D Malfunctioning PCV valve

CMP sensing rotor inspection in section

6E1.

Diag. Flow Table B-4 in Section 6E1.

ECT sensor or MAP sensor in Section

6E1.

Inspection of ECM and its circuit in Sec-

tion 6E1.

Compression check in Section 6A or 6A1.

Valves inspection in Section 6A or 6A1.

Valves spring inspection in Section 6A or

6A1.

Cylinder head inspection in Section 6A or

6A1.

Piston ring inspection in Section 6A or

6A1.

Cylinders, pistons and piston rings

inspection in Section 6A or 6A1.

PCV system inspection in Section 6E1.

ENGINE DIAGNOSIS 6-11

Condition Possible Cause Reference Item

Engine has no power Engine overheating.

Ignition system out of order.

D Defective spark plug

D Faulty ignition coil

Fuel system out of order.

D Fuel pressure out of specification

– Dirty fuel filter

– Dirty or clogged fuel hose or pipe

– Malfunctioning fuel pressure regulator

– Malfunctioning fuel pump

Engine and emission control system

out of order.

D Faulty injector

D Faulty TP sensor, ECT sensor or

MAP sensor

D Faulty ECM

Low compression.

Others

D Dragging brakes

D Slipping clutch

Refer to “Overheating” Section.

Spark plugs in Section 6F.

Ignition coil in Section 6F.

Diag. Flow Table B-3 in Section 6E1.

Fuel injector in Section 6E1.

TP sensor, ECT sensor or MAP

sensor in Section 6E1.

Inspection of ECM and its circuit in

Section 6E1.

Previously outlined.

Diagnosis in Section 5.

Diagnosis in Section 7C.

Improper engine

idling or engine fails

to idle

Ignition system out of order.

D Faulty spark plug

D Faulty ignition coil

Fuel system out of order.

D Fuel pressure out of specification

– Malfunctioning fuel pressure regulator

Engine overheating.

Engine and emission control system

out of order.

D Faulty idle air control system

D Faulty evaporative emission control system

D Faulty injector

D Faulty ECT sensor, TP sensor or

MAP sensor

D Faulty ECM

Low compression.

Others

D Malfunctioning PCV valve

Spark plugs in Section 6F.

Ignition coil in Section 6F.

Diag. Flow Table B-3 in Section 6E1.

Refer to “Overheating” Section.

Diag. Flow Table B-4 in Section 6E1.

Diag. Flow Table B-5 in Section 6E1.

Fuel injector in Section 6E1.

ECT sensor, TP sensor or MAP

sensor in Section 6E1.

Inspection of ECM and its circuit in

Section 6E1.

Previously outlined.

PCV system inspection in Section

6E1.

6-12 ENGINE DIAGNOSIS

Condition Possible Cause Reference Item

Engine hesitates

(Momentary lack of

response as the

accelerator is

depressed.

Can occur at all

vehicle speeds.

Usually most severe

when first trying to

make the vehicle

move, as from a

stop sign.)

Ignition system out of order.

D Spark plug faulty or plug gap as out

of adjustment

Fuel system out of order.

D Fuel pressure out of specification

– Clogged fuel filter

– Faulty fuel pressure regulator

D Clogged fuel filter, hose or pipe

Engine overheating

Engine and emission control system out

of order.

D Faulty injector

D Faulty TP sensor, ECT sensor or MAP

sensor

D Faulty ECM .

Low compression

Spark plugs in Section 6F.

Diag. Flow Table B-3 in Section 6E1.

Fuel pressure check in Section 6E1.

Refer to “Overheating” Section.

Fuel injector in Section 6E1.

TP sensor, ECT sensor or MAP

sensor in Section 6E1.

Inspection of ECM and its circuit in

Section 6E1.

Previously outlined.

Surges

(Engine power variation

under steady

throttle or cruise.

Feels like the vehicle

speeds up and down

with no change in

the accelerator

pedal.)

Ignition system out of order.

D Defective spark plug (excess carbon

deposits, improper gap, and burned

electrodes, etc.)

Fuel system out of order.

D Variable fuel pressure

– Clogged fuel filter

– Kinky or damaged fuel hose and line

– Faulty fuel pressure regulator

Engine and emission control system out

of order.

D Faulty MAP sensor

D Faulty injector

D Faulty ECM

Spark plugs in Section 6F.

Diag. Flow Table B-3 in Section 6E1.

MAP sensor in Section 6E1.

Fuel injector in Section 6E1.

Inspection of ECM and its circuit in

Section 6E1.

ENGINE DIAGNOSIS 6-13

Condition Possible Cause Reference Item

Excessive detonation

(The engine makes

sharp metallic knocks

that change with

throttle opening.

Sounds like pop corn

popping.)

Engine overheating

Ignition system out of order.

D Faulty spark plug

D Improper ignition timing

Fuel system out of order.

D Clogged fuel filter and fuel lines

Engine and emission control system

Refer to “Overheating” Section.

Spark plugs in Section 6F.

Ignition timing in Section 6F.

Fuel pressure check in Section 6E1.

out of order.

D Faulty ECT sensor or MAP sensor

D Faulty injector

D Faulty ECM

Others

D Excessive combustion chamber deposits

ECT sensor or MAP sensor in Section

6E1.

Fuel injector in Section 6E1.

Inspection of ECM and its circuit in Sec-

tion 6E1.

Piston and cylinder head cleaning in

Section 6A or 6A1.

Overheating D Inoperative thermostat

D Poor water pump performance

D Clogged or leaky radiator

D Improper engine oil grade

D Clogged oil filter or oil strainer

D Poor oil pump performance

D Dragging brakes

D Slipping clutch

D Blown cylinder head gasket

Thermostat in Section 6B.

Water pump in Section 6B.

Radiator in Section 6B.

Engine oil and oil filter change in

Section 0B.

Oil pressure check in Section 6A or 6A1.

Diagnosis in Section 5.

Diagnosis in Section 7C.

Cylinder head inspection in Section 6A

or 6A1.

Poor gasoline

mileage

Ignition system out of order.

D Faulty spark plug (improper gap, heavy

deposits, and burned electrodes, etc.)

Engine and emission control system

out of order.

D Fuel pressure out of specification

D Faulty TP sensor, ECT sensor or MAP

sensor

D Faulty injector

D Faulty ECM

Low compression

Others

D Poor valve seating

D Dragging brakes

D Slipping clutch

D Thermostat out of order

D Improper tire pressure

Spark plugs in Section 6F.

Diag. Flow Table B-3 in Section 6E1.

TP sensor, ECT sensor or MAP

sensor in Section 6E1.

Fuel injector in Section 6E1.

Inspection of ECM and its circuit in Sec-

tion 6E1.

Previously outlined.

Valves inspection in Section 6A or 6A1.

Diagnosis in Section 5.

Diagnosis in Section 7C.

Thermostat in Section 6B.

6-14 ENGINE DIAGNOSIS

Condition Possible Cause Reference Item

Excessive engine oil

consumption

Oil entering combustion chamber

D Sticky piston ring

D Worn piston and cylinder

D Worn piston ring groove and ring

D Improper location of piston ring gap

D Worn or damaged valve stem seal

D Worn valve stem

Piston cleaning in Section 6A or 6A1.

Cylinders, pistons and piston rings

inspection in Section 6A or 6A1.

Pistons and piston rings inspection in Sec-

tion 6A or 6A1.

Pistons installation in Section 6A or 6A1.

Valves and cylinder head in Section 6A

or 6A1.

Valves inspection in Section 6A or 6A1.

Low oil pressure D Improper oil viscosity

D Malfunctioning oil pressure switch

D Clogged oil strainer

D Functional deterioration of oil pump

D Worn oil pump relief valve

D Excessive clearance in various sliding

parts

Engine oil and oil filter change in

Section 0B.

Oil pressure switch inspection in

Section 8.

Oil pan and oil pump strainer

cleaning in Section 6A or 6A1.

Oil pump in Section 6A or 6A1.

Engine noise

Note: Before check-

ing the mechanical

noise, make sure

that:

D Ignition timing is

properly adjusted.

D Specified spark

plug is used.

D Specified fuel is

used.

Valve noise

D Improper valve lash

D Worn valve stem and guide

D Weak or broken valve spring

D Warped or bent valve

D Loose camshaft housing bolts

Piston, ring and cylinder noise

D Worn piston, ring and cylinder bore

Connecting rod noise

D Worn crankpin bearing

D Worn crankpin

D Loose connecting rod nuts

D Low oil pressure

Crankshaft noise

D Low oil pressure

D Worn crankshaft journal bearing

D Worn crankshaft journal

D Loose lower crankcase

(bearing cap) bolts

D Excessive crankshaft thrust play

Valve lash in Section 6A or 6A1.

Valves inspection in Section 6A or 6A1.

Valve springs inspection in Section 6A or

6A1.

Valves inspection in Section 6A or 6A1.

Camshafts in Section 6A or 6A1.

Pistons and cylinders inspection in Sec-

tion 6A or 6A1.

Crankpin and connecting rod bearing in-

spection in Section 6A or 6A1.

Crankpin and connecting rod bearing in-

spection in Section 6A or 6A1.

Connecting rod installation in Section 6A

or 6A1.

Previously outlined.

Crankshaft and bearing inspection in

Section 6A or 6A1.

Crankshaft and bearing inspection in

Section 6A or 6A1.

Crankshaft installation in Section 6A or

6A1.

Crankshaft inspection in Section 6A or

6A1.

ENGINE DIAGNOSIS 6-15

Condition Possible Cause Referring Item

Excessive

hydrocarbon (HC)

emission or

Excessive carbon

monoxide (CO)

emission

Ignition system out of order

D Defective spark plug

Fuel system out of order

D Fuel pressure out of specification

Engine and Emission control system

out of order.

D Lead contamination of three way catalytic

converter (if equipped)

D Malfunctioning PCV valve

D Faulty EVAP control system

D Closed loop system (A/F feed back

compensation) fails

– Faulty TP sensor

– Faulty ECT sensor or MAP sensor

– Faulty O

sensor

D Faulty injector

D Faulty ECM

Low compression

Fuel pressure check in Section 6E1.

Check for absence of filler neck

restrictor.

PCV valve in Section 6E1.

EVAP control system check in

Section 6E1.

Check oxygen sensor output voltage

referring to DTC No.14 Diag. Flow

Table in Section 6E1.

Fuel injector in Section 6E1.

Inspection of ECM and its circuit in

Section 6E1.

Previously outlined.

Excessive nitrogen

oxides (NOx)

emission

Fuel system out of order

D Fuel pressure out of specification

Engine and emission control system

D Lead contamination of three way catalytic

converter (if equipped)

D Closed loop system (A/F feed back

compensation) fails (vehicle with O

sensor)

– Faulty TP sensor

– Faulty ECT sensor or MAP sensor

– Faulty O

sensor

D Faulty injector

D Faulty ECM

Fuel pressure check in Section 6E1.

Check for absence of filler neck

restrictor.

Check oxygen sensor output voltage

referring to DTC No.14 Diag. Flow

Table in Section 6E1.

Fuel injector Section 6E1.

Inspection of ECM and its circuit in

Section 6E1.

Engine Diagnosis for Your Suzuki Alto 4 Door Fifth Generation (1998-2003)

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