automotive scope testing bridgwater college. oscilloscope tester an oscilloscope is like a...

AUTOMOTIVE SCOPE AUTOMOTIVE SCOPE TESTINGTESTING

AUTOMOTIVE SCOPE AUTOMOTIVE SCOPE TESTINGTESTING

BRIDGWATER COLLEGEBRIDGWATER COLLEGE

OSCILLOSCOPE TESTEROSCILLOSCOPE TESTER

An oscilloscope is like a An oscilloscope is like a voltmeter. It is connected voltmeter. It is connected across, or in parallel, with across, or in parallel, with the circuit being tested, the circuit being tested, and its most important and its most important use is to give information use is to give information about voltage changes in a about voltage changes in a circuit againts time.circuit againts time.

VOLTAGE

TIME

OSCILLOSCOPE TESTEROSCILLOSCOPE TESTER

The ignition oscilloscope The ignition oscilloscope can have markings on it’s can have markings on it’s screen which are a number screen which are a number of horizontal lines, starting of horizontal lines, starting from 0KV and extending in from 0KV and extending in increments of 5KV on the increments of 5KV on the left and 10KV on the right left and 10KV on the right side (secondary).side (secondary).

VOLTAGE

TIME

OSCILLOSCOPE TESTEROSCILLOSCOPE TESTER The screen can also be read The screen can also be read

from 0V extending in from 0V extending in increments of 5V on the left increments of 5V on the left hand side and in hand side and in increments of 10V on the increments of 10V on the right hand side (primary).right hand side (primary).

The bottom of the screen is The bottom of the screen is marked off in degrees and marked off in degrees and percentage.percentage.

Computer scopes may use Computer scopes may use menus for voltage and time. menus for voltage and time.

VOLTAGE

TIME

SECONARY SECONARY OSCILLOSCOPEOSCILLOSCOPE

PATTERNPATTERN

SCOPE PATTERNSSCOPE PATTERNS

SECONDARY PATTERNSECONDARY PATTERN

PURPOSEPURPOSE

TO IDENTIFY:TO IDENTIFY:

1. OPEN CIRCUITS IN 1. OPEN CIRCUITS IN THE SECONDARY THE SECONDARY IGNITION CIRCUIT.IGNITION CIRCUIT.

2. COMPRESSION 2. COMPRESSION PROBLEMSPROBLEMS..


PURPOSEPURPOSE

TO IDENTIFY:TO IDENTIFY:

1. OPEN CIRCUITS IN 1. OPEN CIRCUITS IN THE SECONDARY THE SECONDARY IGNITION CIRCUIT.IGNITION CIRCUIT.

2. COMPRESSION 2. COMPRESSION PROBLEMSPROBLEMS..

3. FUEL FAULTS3. FUEL FAULTS

4. SPARK PLUG DEFECTS4. SPARK PLUG DEFECTS

5. CONDENSER PROBLEMS5. CONDENSER PROBLEMS

6. POINTS DEFECTS6. POINTS DEFECTS

7. ELECTRONIC IGNITION 7. ELECTRONIC IGNITION PROBLEMSPROBLEMS


1.You are required to build up in your 1.You are required to build up in your work book a complete diagram of a work book a complete diagram of a secondary ignition scope pattern.secondary ignition scope pattern.

2.Answer a number of multi-choice 2.Answer a number of multi-choice questions.questions.

3.List the ignition faults against particular 3.List the ignition faults against particular pictures showing incorrect secondary pictures showing incorrect secondary patterns.patterns.

1.You are required to build up in your 1.You are required to build up in your work book a complete diagram of a work book a complete diagram of a secondary ignition scope pattern.secondary ignition scope pattern.

2.Answer a number of multi-choice 2.Answer a number of multi-choice questions.questions.

3.List the ignition faults against particular 3.List the ignition faults against particular pictures showing incorrect secondary pictures showing incorrect secondary patterns.patterns.

SECONDARYSECONDARY PATTERNPATTERN

FIRING LINE FIRING LINE = =

a

a


FIRING LINEFIRING LINE

Voltage required to establish the spark.Voltage required to establish the spark.

Normally 5 to 15 KV. Maximum Normally 5 to 15 KV. Maximum variation between cylinders 3KVvariation between cylinders 3KV


The required firing voltage is affected by The required firing voltage is affected by secondary circuit gaps, cylinder secondary circuit gaps, cylinder compression and temperature, fuel compression and temperature, fuel mixture and ignition timing.mixture and ignition timing.


SPARKLINESPARKLINE = = b

FIRING LINE

b


SPARK LINESPARK LINE

Voltage required to maintain the spark. Voltage required to maintain the spark. Max. height 3KV Max. height 3KV Max. slope 1.5KV Max. slope 1.5KV


The required spark voltage and The required spark voltage and characteristics of the spark line are characteristics of the spark line are affected by the secondary circuit affected by the secondary circuit resistance, spark plug and cylinder resistance, spark plug and cylinder conditions.conditions.


COIL OSCILLATIONS COIL OSCILLATIONS ==

FIRING LINE

SPARK LINE

c

c


INTERMEDIATE OSCILLATIONSINTERMEDIATE OSCILLATIONS

Dissipation of remaining coil energy by Dissipation of remaining coil energy by condenser action. condenser action.

Normally at least 4 gradually Normally at least 4 gradually diminishing oscillations at 2000RPM.diminishing oscillations at 2000RPM.


The number of coil oscillations is The number of coil oscillations is affected by engine speed and defects in affected by engine speed and defects in the coil, condenser, or primary circuit.the coil, condenser, or primary circuit.


START OF DWELLSTART OF DWELL COIL BUILDING COIL BUILDING UP IT’S MAGNETIC FIELD UP IT’S MAGNETIC FIELD = = dd

d

FIRING LINE

SPARKLINE


START OF DWELLSTART OF DWELL

The points closed signal is affected by The points closed signal is affected by points condition, alignment, spring points condition, alignment, spring tension and defects in the coil or primary tension and defects in the coil or primary circuit.circuit.


Points open signal is affected by points Points open signal is affected by points condition and gap, or arcing due to poor condition and gap, or arcing due to poor condenser action, primary circuit defects condenser action, primary circuit defects or high primary current.or high primary current.

ELECTRONIC IGNITIONELECTRONIC IGNITION Start of dwell the amplifier turns on, the Start of dwell the amplifier turns on, the end of dwell the amplifier turns off.end of dwell the amplifier turns off.

All modern amplifiers are fitted with All modern amplifiers are fitted with

vary dwell. Vary dwell will alter the vary dwell. Vary dwell will alter the dwell angle with changes of speed, if the dwell angle with changes of speed, if the engine speed is low then the dwell angle engine speed is low then the dwell angle is small, as the engine speed increases the is small, as the engine speed increases the dwell angle will also increase providing a dwell angle will also increase providing a constant energy ingnition system.constant energy ingnition system.

PRIMARY OSCILLOCOPEPRIMARY OSCILLOCOPEPATTERNPATTERN

PRIMARY PATTERNPRIMARY PATTERN

Since any voltage variation in the primary Since any voltage variation in the primary ignition circuit will be reflected in secondary ignition circuit will be reflected in secondary circuit testing, it is not always necessary to use circuit testing, it is not always necessary to use primary circuit testing to determine the primary circuit testing to determine the general condition of the ignition system.general condition of the ignition system.

The trace patterns of the primary circuit are The trace patterns of the primary circuit are very simular to that of the secondary. The very simular to that of the secondary. The voltage values represented in the primary voltage values represented in the primary patterns are much lower than the secondary patterns are much lower than the secondary patterns(primary is measured in VOLTS).patterns(primary is measured in VOLTS).

PRIMARY PATTERNPRIMARY PATTERN

The diagram below shows a single The diagram below shows a single cylinder primary patterncylinder primary pattern

250V Firing section

Intermediate section

Dwellsection

MULTI-CHOICEMULTI-CHOICEQUESTIONSQUESTIONS

TYPES OF OSCILLOSCOPETYPES OF OSCILLOSCOPEPATTERNSPATTERNS

SECONDARY PATTERNSECONDARY PATTERN1. STATE THE PATTERN TYPE BELOW 1. STATE THE PATTERN TYPE BELOW

a) Superimposed b) Single cylinder a) Superimposed b) Single cylinder c) Raster d) Display c) Raster d) Display

2. State the permitted variation between 2. State the permitted variation between cylinders a) 8KV b) 12KV c) 3KV d) 4KVcylinders a) 8KV b) 12KV c) 3KV d) 4KV

1 3 4 2

SECONDARY PATTERNSECONDARY PATTERN3. NAME THE TYPE OF PATTERN BELOW 3. NAME THE TYPE OF PATTERN BELOW

a) Superimposed b) Raster c) Displaya) Superimposed b) Raster c) Display


4. Name the pattern below 4. Name the pattern below a) Raster b) Single cylinder c) Display a) Raster b) Single cylinder c) Display d) Superinposed d) Superinposed

IGNITION SYSTEMIGNITION SYSTEMFAULT DIAGNOSIS FAULT DIAGNOSIS


MAKE A LIST AGAINST THE MAKE A LIST AGAINST THE FOLLOWING FAULTSFOLLOWING FAULTS

1. No firing line or spark line1. No firing line or spark line


2. Low firing line and long spark line2. Low firing line and long spark line

3KV


3. Normal firing line and short and steep 3. Normal firing line and short and steep sparkline sparkline

8KV5KV


4. High firing line short spark line4. High firing line short spark line

16 KV


5. Hashing when points close and open5. Hashing when points close and open

8KV


6. Pattern is upside down6. Pattern is upside down

SECONDARY PATTERNSECONDARY PATTERN7. No 3 cylinder has a low firing line and long 7. No 3 cylinder has a low firing line and long

sparklinesparkline

1

3

4

2

SECONDARY PATTERNSECONDARY PATTERN8. No 4 cylinder dwell section is out of line with 8. No 4 cylinder dwell section is out of line with

the other cylindersthe other cylinders

1

3

4

2


9. Lack of coil oscillations9. Lack of coil oscillations

AUTOMOTIVE SCOPEAUTOMOTIVE SCOPECONNECTIONS TO CONNECTIONS TO

VEHICLEVEHICLE

SCOPE CONNECTIONSCOPE CONNECTION

Identify the parts of the engine the Identify the parts of the engine the connections are made.connections are made.

a b c d e f g

BOOM

SCOPE CONNECTIONSSCOPE CONNECTIONS

a) Red clamp to_____________a) Red clamp to_____________

b) Chrome clamp to___________b) Chrome clamp to___________

c) Green clip to_______________c) Green clip to_______________

d) Yellow clip to______________d) Yellow clip to______________

e) Black clip to_______________e) Black clip to_______________

f) Red clip to_________________f) Red clip to_________________

g) Green clamp to____________g) Green clamp to____________

automotive scope testing bridgwater college. oscilloscope tester an oscilloscope is like a...

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