Ford Festiva. Instruction - part 59

TUNE-UP TROUBLE SHOOTING - GAS ENGINE VEHICLES 

BASIC SPARK PLUG TROUBLE SHOOTING CHARTS 

Faulty solenoid switch, switch connections or relay

Check all wiring between 

relay and solenoid or replace 

relay or solenoid as necessary

Broken lead or loose soldered connections

Repair wire or wire 

connections as necessary

Solenoid Plunger Vibrates When Switch is Engaged

Weak battery

Charge or replace battery as 

necessary

Solenoid contacts corroded

Clean contacts or replace 

solenoid

Faulty wiring

Check all wiring leading to 

solenoid

Broken connections inside switch cover

Repair connections or replace 

solenoid

Open hold-in wire

Replace solenoid

Low Current Draw

Worn brushes or weak

Replace brushes or brush 

springs as necessary

High Pitched Whine During Cranking Before Engine Fires but Engine Fires and Cranks Normally

Distance too great between starter pinion and flywheel

Align starter or check that 

correct starter and flywheel 

are being used

High Pitched Whine After Engine Fires With Key released. Engine Fires and Cranks Normally

Distance too small between starter pinion and flywheel

Flywheel runout contributes 

to the intermittent nature

NOTE:

This is GENERAL information. This article is not intended to be specific to any unique situation or 
individual vehicle configuration. The purpose of this Trouble Shooting information is to provide a list 
of common causes to problem symptoms. For model-specific Trouble Shooting, refer to SUBJECT, 
DIAGNOSTIC, or TESTING articles available in the section(s) you are accessing.

CONDITION & POSSIBLE CAUSE

CORRECTION

Normal Spark Plug Condition

Light Tan or Gray deposits

No Action

Electrode not burned or fouled

No Action

Gap tolerance not changed

No Action

Cold Fouling or Carbon Deposits

Overrich air/fuel mixture

Adjust air/fuel mixture, see 

ENGINE PERFORMANCE 

section

Faulty choke

Replace choke assembly, see 

ENGINE PERFORMANCE 

section

Clogged air filter

Clean and/or replace air filter

Incorrect idle speed or dirty carburetor

Reset idle speed and/ or clean 

carburetor

Faulty ignition wires

Replace ignition wiring

Prolonged operation at idle

Shut engine off during long 

idle

Sticking valves or worn valve guide seals

Check valve train

Wet Fouling or Oil Deposits

Worn rings and pistons

Install new rings and pistons

Excessive cylinder wear

Rebore or replace block

Excessive valve guide clearance

Worn or loose bearing

Gap Bridged

Deposits in combustion chamber becoming fused to electrode

Clean combustion chamber of 

deposits

Blistered Electrode

Engine overheating

Check cooling system

Wrong type of fuel

Replace with correct fuel

Loose spark plugs

Retighten spark plugs

Over-advanced ignition timing

Reset ignition timing see 

ENGINE PERFORMANCE

Pre-Ignition or Melted Electrodes

Incorrect type of fuel

Replace with correct fuel

Incorrect ignition timing

Reset ignition timing see 

ENGINE PERFORMANCE

Burned valves

Replace valves

Engine Overheating

Check cooling system

Wrong type of spark plug, too hot

Replace with correct spark 

BASIC ELECTRONIC IGNITION TROUBLE SHOOTING CHARTS 

BASIC ELECTRONIC IGNITION TROUBLE SHOOTING CHARTS - USING OSCILLOSCOPE PATTERNS 

plug, see ENGINE 

PERFORMANCE

Chipped Insulators

Severe detonation

Check for over-advanced 

timing or combustion

Improper gapping procedure

Re-gap spark plugs

Rust Colored Deposits

Additives in unleaded fuel

Try different fuel brand

Water In Combustion Chamber

Blown head gasket or cracked head

Repair or replace head or head 

gasket

NOTE:

Before diagnosing an electronic ignition system, ensure that all wiring is connected properly between 
distributor, wiring connector and spark plugs. Ignition problem will show up either as: Engine Will Not 
Start or Engine Runs Rough.

CONDITION & POSSIBLE CAUSE

CORRECTION

Engine Won't Start

Open circuit between distributor and bulkhead connector

Repair circuit

Open circuit between bulkhead connector and ignition switch

Repair circuit

Open circuit between ignition switch and starter solenoid

Repair circuit

Engine Runs Rough

Fuel lines leaking or clogged

Tighten fitting, remove 

restriction

Initial timing incorrect

Reset ignition timing see 

ENGINE PERFORMANCE

Centrifugal advance malfunction

Repair distributor advance

Defective spark plugs or wiring

Replace plugs or plug wiring

Component Failure

Spark arc-over on cap, rotor or coil

Replace cap, rotor or or coil

Defective pick-up coil

Replace pick-up coil

Defective ignition coil

Replace ignition coil

Defective vacuum unit

Replace vacuum unit

Defective control module

Replace control module

CONDITION & POSSIBLE CAUSE

CORRECTION

Firing Voltage Lines are the Same, but Abnormally High

Retarded ignition timing

Reset ignition timing, see 

ENGINE PERFORMANCE 

section

Fuel mixture too lean

Readjust carburetor, see 

ENGINE PERFORMANCE

High resistance in coil wire

Replace coil wire

Corrosion in coil tower terminal

Clean and/or replace coil

Corrosion in distributor coil terminal

Clean and/or replace 

distributor cap

Firing Voltage Lines are the Same but Abnormally Low

Fuel mixture too rich

Readjust carburetor, see 

ENGINE PERFORMANCE

Breaks in coil wire causing arcing

Replace coil wire

Cracked coil tower causing arcing

Replace coil

Low coil output

Replace coil

Low engine compression

Determine cause and repair

One or More, But Not All Firing Voltage Lines are Higher Than Others

Carburetor idle mixture not balanced

Readjust carburetor, see 

ENGINE PERFORMANCE

EGR valve stuck open

Clean and/or replace valve

High resistance in spark plug wires

Replace spark plug wires

Cracked or broken spark plug insulator

Replace spark plugs

Intake vacuum leak

Repair leak

Defective spark plugs

Replace spark plugs

Corroded spark plug terminals

Replace spark plugs

One or More, But Not All Firing Voltage Lines Are Lower Than Others

Curb idle mixture not balanced

Readjust carburetor, see 

ENGINE PERFORMANCE

Breaks in plug wires

Replace plug wires causing 

arcing

Cracked coil tower causing arcing

Replace coil

Low compression

Determine cause and repair

Defective spark plugs

Replace spark plugs

BASIC DRIVEABILITY PROBLEMS TROUBLE SHOOTING 

Corroded spark plugs

Replace spark plugs

Cylinders Not Firing

Cracked distributor cap terminals

Replace distributor cap

Shorted spark plug wire

Determine cause and repair

Mechanical problem in engine

Determine cause and repair

Defective spark plugs

Replace spark plugs

Spark plugs fouled

Replace spark plugs

CONDITION & POSSIBLE CAUSE

CORRECTION

Hard Starting

Binding carburetor linkage

Eliminate binding

Binding choke linkage

Eliminate binding

Binding choke piston

Eliminate binding

Restricted choke vacuum

Check vacuum lines for 

blockage

Worn or dirty needle valve and seat

Clean carburetor, see ENGINE 

PERFORMANCE

Float sticking

Readjust or replace float see 

the ENGINE 

PERFORMANCE section

Incorrect choke adjustment

Reset choke adjustment see 

ENGINE PERFORMANCE

Defective coil

Replace coil

Improper spark plug gap

Regap spark plugs

Incorrect ignition timing

Reset ignition timing see 

ENGINE PERFORMANCE

Detonation

Over-advanced ignition timing

Reset ignition timing see 

ENGINE PERFORMANCE

Defective spark plugs

Replace spark plugs

Fuel lines clogged

Clean fuel lines

EGR system malfunction

Check and repair EGR system

PCV system malfunction

Repair PCV system

Vacuum leaks

Check and repair vacuum 

system

Loose fan belts

Tighten or replace fan belts, 

see ENGINE 

PERFORMANCE

Restricted airflow

Remove restriction

Vacuum advance malfunction

Check distributor operation

Dieseling

Binding carburetor linkage

Eliminate binding

Binding throttle linkage

Eliminate blinding

Binding choke linkage or fast idle cam

Eliminate binding

Defective idle solenoid

Replace idle solenoid see 

ENGINE PERFORMANCE

Improper base idle speed

Reset idle speed, see see 

ENGINE PERFORMANCE

Incorrect ignition timing

Reset ignition timing see 

ENGINE PERFORMANCE

Incorrect idle mixture setting

Reset idle mixture, see 

ENGINE PERFORMANCE

Faulty Acceleration

Incorrect ignition timing

Reset ignition timing see 

ENGINE PERFORMANCE

Engine cold and choke too lean

Adjust choke and allow engine 

to warm-up

Defective spark plugs

Replace spark plugs

Defective coil

Replace coil

Faulty Low Speed Operation

Clogged idle transfer slots

Clean idle transfer slots, see 

FUEL

Restricted idle air bleeds and passages

Disassemble and clean 

carburetor, see FUEL

Clogged air cleaner

Replace air filter

Defective spark plugs

Replace spark plugs

Defective ignition wires

Replace ignition wire see 

ENGINE PERFORMANCE

Defective distributor cap

Replace distributor cap

Faulty High Speed Operation

Incorrect ignition timing

Reset ignition timing see 

ENGINE PERFORMANCE

Defective distributor centrifugal advance

Replace advance mechanism

Defective distributor vacuum advance

Replace advance unit

Incorrect spark plugs or plug gap

Check gap and/or replace 

spark plugs

Faulty choke operation

Check choke and repair as 

required

Clogged vacuum passages

Remove restrictions

Improper size or clogged main jet

Check jet size and clean, see 

FUEL

Restricted air cleaner

Check filter and replace as 

necessary

Defective distributor cap, rotor or coil

Replace cap, rotor or coil

Misfire at All Speeds

Defective spark plugs

Replace spark plugs

Defective spark plug wires

Replace spark plug wires

Defective distributor cap, rotor, or coil

Replace cap, rotor, or coil

Cracked or broken vacuum hoses

Replace vacuum hoses

Vacuum leaks

Repair vacuum leaks

Fuel lines clogged

Remove restriction

Hesitation

Cracked or broken vacuum

Replace vacuum hoses hoses

Vacuum leaks

Repair Vacuum leaks

Binding carburetor linkage

Eliminate binding

Binding throttle linkage

Eliminate binding

Binding choke linkage or fast idle cam

Eliminate binding

Improper float setting

Readjust float setting, see 

FUEL

Cracked or broken ignition wires

Replace ignition wires

Rough Idle, Missing or Stalling

Incorrect curb idle or fast idle speed

Reset idle speed, see see 

ENGINE PERFORMANCE

Incorrect basic timing

Reset ignition timing see 

ENGINE PERFORMANCE

Improper idle mixture adjustment

Reset idle mixture, see 

ENGINE PERFORMANCE

Improper feedback system operation

Check feedback system see 

ENGINE PERFORMANCE

Incorrect spark plug gap

Reset spark plug gap, see 

ENGINE PERFORMANCE

Moisture in ignition components

Dry components

Loose or broken ignition wires

Replace ignition wires

Damaged distributor cap or or rotor

Replace distributor cap or 

rotor

Faulty ignition coil

Replace ignition coil

Fuel filter clogged or worn

Replace fuel filter

Damaged idle mixture screw

Replace idle mixture screw, 

see FUEL

Improper fast idle cam adjustment

Reset fast idle cam adjustment, 

see TUNE- see ENGINE 

PERFORMANCE

Improper EGR valve operation

Replace EGR valve

Faulty PCV valve air flow

Replace PCV valve

Choke binding or improper choke setting

Reset choke or eliminate 

binding

Vacuum leak

Repair vacuum leak

Improper float bowl fuel level

Reset float adjustment, see 

FUEL

Clogged air bleed or idle passages

Clean carburetor passages, see 

FUEL

Clogged or worn air cleaner filter

Replace air filter

Faulty choke vacuum diaphragm

Replace diaphragm, see 

ENGINE PERFORMANCE

Exhaust manifold heat valve inoperative

Replace heat valve

Improper distributor spark advance

Check distributor operation

Leaking valves or valve components

Check and repair valvetrain

Improper carburetor mounting

Remove and remount 

carburetor

Excessive play in distributor shaft

Replace distributor

Loose or corroded wiring connections

Repair or replace as required

Engine Surges

Improper PCV valve airflow

Replace PCV valve

Vacuum leaks

Repair vacuum leaks