This is Module 5 for Quarter 1 of the Special Program in Technical Vocational Education (SPTVE), IA-Automotive Servicing NC II, for Grade 10. It covers servicing the ignition system: checking the ignition coil, ballast resistor, high tension cable resistance, and distributor assembly. It is a self-learning module (Alternative Delivery Mode) from DepEd Cordillera Administrative Region, and it is meant for Week 5 of the quarter.
What learners will learn
The module targets competency code SPTVE_IAAUS9-12SIS-IIc-g-7:
- LO 2. Check ignition coil, ballast resistor, high tension cable resistance
- LO 3. Check distributor assembly
After the module, learners are expected to:
- Know the steps in inspecting and checking the ignition coil, ballast resistor, high tension cables, and distributor assembly
- Check or test ignition system components
- Adjust ignition timing
- Relate the topic to real-life situations
What the module covers
The module explains that the ignition system produces an electric spark to ignite the fuel-air mixture at the right time. Its parts wear over time, so each one must be checked and tested. The discussion has eight parts:
- Ignition coil. A spark test using a spark plug and a ground wire jumper. A good spark means the coil is good. If not, check for about 12 VDC at the coil terminals. A resistance check with an ohmmeter confirms the coil’s condition.
- Ballast resistor. Remove it and check it with an ohmmeter for continuity and standard resistance. No continuity means it is defective. Replace it if the resistance is too high.
- High tension cables. Four tests: lead resistance, voltage leaks, insulation, and spark plug wire resistance. The leak and insulation tests run a grounded screwdriver about an inch from each wire with the engine idling. A spark or cracking sound means the wires should be replaced.
- Ignition system wiring. First, preliminary checks of the battery, wires, and distributor cap. Then voltmeter and ohmmeter tests for voltage drop in the primary circuit. Too much voltage drop causes hard starting and poor performance.
- Distributor cap and rotor. Check the cap for cracks, carbon tracking, moisture, debris, a worn rotor button, and pitted or charred terminals. Check the rotor for charring or pitting. Make sure the rotor screw and dust cover are in place.
- Dwell angle and RPM. How to measure dwell with a dwell meter and adjust the contact point gap. The gap can be set with the distributor on the engine or held in a bench vise.
- Ignition timing. How to check and set base timing with a timing light.
- Electronic ignition troubleshooting. With the ignition on and the engine off, test for battery voltage at the coil’s positive terminal. If there is none, check for an open circuit at the ignition switch or wiring.
Key terms and specifications
- Dwell angle: the amount of rotation through which the breaker points stay closed to energize the ignition primary coil.
- RPM (revolutions per minute): how many times the crankshaft makes one full rotation every minute.
- Ignition timing: the point, in degrees of crankshaft rotation, at which the spark plugs fire. It is measured in degrees before or after Top Dead Center (TDC) of the compression stroke.
- Contact points and camlobe: when the points are closed, the magnetic field builds up in the coil. When they open, the field collapses and voltage goes to the spark plugs. The camlobe on the distributor opens and closes the points.
The module gives these values:
| Check | Value given in the module |
|---|---|
| Ignition coil primary resistance | 0.4 to 0.6 ohms |
| Ignition coil secondary resistance | 5,000 to 7,200 ohms |
| Ballast resistor | 5 ohms |
| High tension lead | Replace the set if over 25,000 ohms or over the computed figure |
| Suppression plug caps | 5,000 to 10,000 ohms |
| Voltage drop, battery to coil | 0.2 volts or less |
| Primary resistor | 1.3 to 1.4 ohms |
| Voltage drop while cranking | Not over 0.1 volt |
| Contact point gap (without igniter) | 0.45 mm |
| Dwell, 4-cylinder engine | 51° (50° to 52°) |
If the dwell angle is below the specification, the point gap is too big. If it is above, the gap is too small. When the engine is raised to about 1,000 rpm and 1,500 rpm, the dwell reading should not change by more than two or three degrees.
Setting ignition timing
The module lists these steps:
- Prepare the supplies, materials, tools, and equipment.
- Connect the timing light and start the engine.
- Let the engine idle at the manufacturer’s recommended rpm.
- Aim the timing light at the timing indicator and compare the marks with the manufacturer’s specification.
- If the mark is not at the specified location, rotate the distributor until it is.
- Tighten the distributor hold-down bolt to the specified torque and recheck the timing.
- Reconnect the vacuum advance hose and anything else that was disconnected.
- Road test the vehicle.
The module’s example: if the specification is 10 degrees BTDC and the reading is 3 degrees BTDC, the timing is retarded by 7 degrees. The timing light flashes every time the number 1 spark plug fires.
Safety reminders
- Never short a plug lead to the dipstick, rocker arm cover, battery, or other parts that may not be directly grounded. Oil fumes or hydrogen can explode.
- Keep hands away from rotating parts. Remove necklaces, rings, and watches.
- Never point the timing light at anyone, especially at the eyes.
- Do not puncture cables with test probes. Never bend the movable point arm by hand.
- When replacing contact points, also replace the condenser with one of the required capacitance.
- Always follow the service manual.
How to use this module
- Learners: Answer the 15-item pretest (What I Know) before anything else. Then work through the parts in order: What’s In (draw the ignition wiring diagram), What’s New, What Is It, What’s More (match pictures to procedures), What I Have Learned, What I Can Do, the 15-item post-assessment, and the Additional Activity (list the ignition timing steps). Write all answers on a separate sheet. Check your work honestly with the answer key, then return the module to your teacher.
- Parents and guardians: Support your child’s home study. Remind them to use separate sheets and not to write on the module.
- Teachers and facilitators: Orient learners on how to use the module and track their progress. The answer key covers the pretest, the matching activity, the post-assessment, and the Additional Activity. The reflection and real-life tasks are open-ended (answers may vary).
Frequently asked questions
What grade and quarter is this module for?
It is for Grade 10 SPTVE IA-Automotive Servicing NC II, Quarter 1, Module 5, intended for Week 5 of the quarter.
What competency does the module cover?
It covers competency code SPTVE_IAAUS9-12SIS-IIc-g-7: LO 2, check ignition coil, ballast resistor, and high tension cable resistance, and LO 3, check distributor assembly.
What resistance should the ignition coil have?
The module gives 0.4 to 0.6 ohms for the primary coil and 5,000 to 7,200 ohms for the secondary coil, both measured with an ohmmeter.
Does the module have an answer key?
Yes. It has answers for the pretest, the matching activity, the post-assessment, and the Additional Activity. The reflection and real-life application tasks have no fixed answers.
What is dwell angle?
Dwell angle is the amount of rotation through which the breaker points stay closed to energize the ignition primary coil. The module gives 51 degrees (50 to 52) for a 4-cylinder engine.
Full text of the module
The text below is a transcription of the PDF above, as printed.
Special Program in Technical Vocational Education
Quarter 1 – Module 5 Servicing Ignition System (Checking ignition coil, ballast resistor, high tension cable resistance and distributor assembly) Automotive Servicing NC II
[illustration: students reading and writing with a globe, lamp, and a teacher at a desk]
CO_Q1_TLE 10_Module 5
[transcriber’s note: this page repeats the cover title block in a different layout]
Special Program in Technical Vocational Education
Quarter 1 – Module 5 Servicing Ignition System (Checking ignition coil, ballast resistor, high tension cable resistance and distributor assembly) Automotive Servicing NC II
IA-Automotive Servicing – Grade 10 Alternative Delivery Mode Quarter 1 – Module 5: Servicing Ignition System (Checking ignition coil, ballast resistor, high tension cable resistance and distributor assembly)
Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit. Such agency or office may, among other things, impose as a condition the payment of royalties.
Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this module are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them.
Published by the Department of Education Secretary: Leonor Magtolis Briones Undersecretary: Diosdado M. San Antonio
Development Team of the Module
Writer: Aldrin T. Bongsian & Pablo B. Mariacos Editors: Reviewer: Jonalyn C. Ambrona Mary Jane N. Malihod
Illustrator: Layout Artist: Management Team: Estela Leon-Cariño, Carmel F. Meris, Rosita C. Agnasi, Federico P. Martin, Christopher C. Benigno, Juliet C. Sannad, Mary Jane N. Malihod, Armi Victoria Fiangaan, Brenda M. Cariño
Printed in the Philippines by:
Department of Education – Cordillera Administrative Region
Office Address: Wangal, La Trinidad, Benguet Telefax: (074) -422 -4074 E-mail Address: car@deped.gov.ph
Introductory Message
This Self-Learning Module (SLM) is prepared so that you, our dear learners, can continue your studies and learn while at home. Activities, questions, directions, exercises, and discussions are carefully stated for you to understand each lesson.
Each SLMS is composed of different parts. Each part shall guide you step-by-step as you discover and understand the lesson prepared for you.
Pre-tests are provided to measure your prior knowledge on lessons in each SLM. This will tell you if you need to proceed on completing this module or if you need to ask your facilitator or your teacher’s assistance for better understanding of the lesson. At the end of each module, you need to answer the post-test to self-check your learning. Answer keys are provided for each activity and test. We trust that you will be honest in using these.
In addition to the material in the main text, Notes to the Teacher are also provided to our facilitators and parents for strategies and reminders on how they can best help you on your home-based learning.
Please use this module with care. Do not put unnecessary marks on any part of this SLM. Use a separate sheet of paper in answering the exercises and test. And read the instructions carefully before performing each task.
If you have questions in using this SLM or any difficulty in answering the tasks in this module, do not hesitate to consult your teacher or facilitator.
Thank you.
Notes to the Teacher
This contains helpful tips or strategies that will help you in guiding the learner.
For the facilitator:
Hi, as a facilitator you are expected to orient the learners on how to use this module. You also need to keep track of the learners’ progress while allowing them to manage their own learning. Kindly, advise the learner’s parents or guardians of the same procedure since they will be the primary supporters in the learners’ progress. Please, do not forget to remind the learner to use separate sheets in answering all of the activities found in the learning module.
For the learner:
Hello learner, Welcome to the Automotive Servicing NC II Alternative Delivery Mode (ADM) Module on Servicing Ignition System (Checking ignition coil, ballast resistor, high tension cable resistance and distributor assembly). I hope you are
ready to progress in your Grade 10 SPTVE in Automotive with this learning module. This is designed to provide you with interactive tasks to further develop the desired learning competencies prescribed in our curriculum. With this, you are expected to appreciate staking through the information and activity given.
This module has the following parts and corresponding icons:
| ICON | LABEL | DETAIL |
|---|---|---|
| What I Need to Know | This contains the learning objectives which you need to accomplish. | |
| What I know | This evaluates what you know about the lesson you are to learn. | |
| What’s In | This connects the current lesson with a topic necessary in your understanding. | |
| What’s New | This introduces the lesson through an activity. | |
| What Is It | This contains a brief discussion of the learning module lesson. | |
| What’s More | These are activities to check your understanding of the lesson. | |
| What I Have Learned | This summarizes the important ideas presented in the lesson. | |
| What I Can Do | This is a real-life application of what you have learned. | |
| Assessment | This is a post assessment of what you have learned. | |
| Additional Activity | This is an activity that will strengthen your knowledge about the lesson. |
At the end of this module you will also find:
References: This is a list of all sources used in developing this module. Answer Sheet: This is where you will write your answers.
TABLE OF CONTENTS
What I Need to Know ….. 1 What I Know ….. 2 What’s In ….. 3 What’s New ….. 4 What Is It ….. 5 What’s More ….. 19 What I Have Learned ….. 21 What I Can Do ….. 21 Post-Assessment ….. 22 Additional Activity ….. 23 Answer Key ….. 24 References ….. 24
LESSON 5
Checking ignition coil, ballast resistor, high tension cable resistance and distributor assembly
The following are some reminders in using this module:
- Use the module with care. Do not put unnecessary mark/s on any part of the module. Use a separate sheet of paper in answering the exercises.
- Don’t forget to answer What I Know before moving on to the other activities included in the module.
- Read the instruction carefully before doing each task.
- Observe honesty and integrity in doing the tasks and checking your answers.
- Finish the task at hand before proceeding to the next.
- Return this module to your teacher/facilitator once you are through with it.
If you encounter any difficulty in answering the tasks in this module, do not hesitate to consult your teacher or facilitator. Always bear in mind that you are not alone.
We hope that through this material, you will experience meaningful learning and gain deep understanding of the relevant competencies. You can do it!
[illustration: hand pressing a button icon]
What I Need to Know
This module was designed and written to guide you to acquire the learning competencies and develop your skills in Checking the Ignition Coil, Ballast Resistor, High Tension Cable Resistance and Distributor Assembly in IA- Automotive Servicing. The scope of this module permits it to be used in many different learning situations. The language used recognizes the diverse vocabulary level of students. The lessons are arranged to follow the standard sequence of the course. However, the order in which you read the module can be changed to correspond with the textbook you are now using.
| Quarter/Week | Q1/W5 |
|---|---|
| Learning Competency Code | SPTVE_IAAUS9-12SIS-IIc-g-7 |
| Learning Competency | LO 2. Check Ignition Coil, Ballast Resistor, High Tension Cable Resistance LO 3. Check Distributor Assembly. |
Learning Objectives:
After going through this module, you are expected to:
- familiarize the steps in inspecting and checking ignition coil, ballast resistor high tension cables and distributor assembly;
- check or test ignition system components,
- adjust ignition timing and;
- relate the topic on real-life situation.
What I Know
Pre-Test/Assessment
Multiple choice
Direction: Choose the LETTER of the best answer. Write your answer in the answer sheet.
- When checking the ignition coil primary resistance using ohmmeter, the resistance should be _____ ohms?
- A. 0.4 to 0.6
- B. 0.6 to 0.8
- C. 0.8 to 0.10
- D. 0.10 to 0.12
- When checking the ignition coil secondary resistance by using an ohmmeter the resistance should be _____ ohms?
- A. 5000 to 7200
- B. 5000 to 7500
- C. 7500 to 8000
- D. 7500 to 8500
- When checking ballast resistor for resistance, resistance should be?
- A. 3 ohms
- B. 5 ohms
- C. 7 ohms
- D. 8 ohms
- When adjusting contact point clearance, the gap should be?
- A. 0.12 in
- B. 0.14 in
- C. 0.18 in
- D. 0.22 in
- It measures how many times the engine’s crankshaft makes one full rotation every minute, and along with it, how many times each piston goes up and down in its cylinder?
- A. RPM
- B. Speedometer
- C. Tachometer
- D. all of the above
- It pertains to the amount of rotation through which breaker points remain closed to energize the ignition primary coil.
- A. Dwell angle
- B. Dwell
- C. Angle
- D. None of the following
- It is the measurement, in degrees of crankshaft rotation, of the point at which the spark plugs fire in each of the cylinders. It is measured in degrees before or after Top Dead Center (TDC) of the compression stroke.
- A. Ignition timing
- B. Ignition system
- C. Timing
- D. RPM
- The tool that is used in checking timing?
- A. Ignition timing
- B. Ignition system
- C. Timing light
- D. RPM
- If the timing mark is not at the specified location, rotate the _____ until the mark is at the specified location.
- A. Distributor
- B. Ignition Coil
- C. Ignition Switch
- D. all of the above
- The two places the ignition timing marks can be located?
- A. Camshaft and crankshaft sprocket
- B. Distributor and points
- C. Harmonic balancer and flywheel
- D. Water pump pulley and fan belt
- The contact points position where magnetic field builds up in the coil.
- A. Close
- B. Open
- C. Both
- D. None of the above
- The contact points position where the magnetic field collapses and voltage is sent to the spark plugs.
- A. Close
- B. Open
- C. Both
- D. None of the above
- The part of the distributor assembly that directly opens and closes the contact point?
- A. The camshaft
- B. The distributor cam/Camlobe
- C. The distributor shaft
- D. A spring
[transcriber’s note: the section heading for items 14 and 15 appears on an earlier page and is not on this page]
- A system that is responsible in delivering an electric spark in the engine combustion chamber, at exactly the right time, which will ignite the mixture of petrol and air.
A. Charging system B. Ignition system C. Lighting System D. Starting system
- When checking ignition timing, the timing light flashes every time the spark plug number _____________ fires.
A. 1 B. 2 C.3 D. 4
What’s In
Directions: Draw and connect the ignition system wiring diagram in the given answer sheet if it fits otherwise, use another paper. Connect ONLY the terminals that has an arrow.
[chart: wiring diagram; ignition system components for wiring, unnumbered. Labels printed: “AM”, “ST”, “ACC”, “IGN”, “Ignition switch”, “COIL” with “+” and “−” terminals, “DISTRIBUTOR”, and a spark plug. Blue arrows mark the terminals to connect. The battery has “+” and “−” terminals.]
What’s New
Direction: In one sentence, describe what the pictures all about. Write your answer in the answer sheet.
[photo: hand holding an ignition coil over an engine]
[photo: hands inserting a spark plug into a engine part]
[photo: multimeter test leads connected to an ignition coil]
[photo: hands working on a distributor with a screwdriver]
What Is It
CHECKING AND TESTING IGNITION SYSTEM COMPONENTS
Previously we have learned that ignition system is the system that is responsible in producing an electric spark to ignite the fuel–air mixture at the right point in time. However, because ignition system is composed of many different components that wears as time goes by that causes malfunction to the engine, checking and testing must be done to ensure the functional capacity of each components.
I-IGNITION COIL
[photo: ignition coil with a black body, metal bracket, and orange terminal]
A. Inspect and Test Ignition Coil
Prepare the supplies, materials, tools and equipment needed.
Locate the ignition coil and disconnect the coil cable from the distributor cap.
Have a spark plug then insert it’s terminal to the other end of the coil cable which was just disconnected.
Get and connect a wire to the threaded portion of the spark plug.
Locate the negative terminal of the ignition coil then disconnect the wire that is connected to it.
Connect the other end of the wire that is connected on the threaded part of the spark plug to the ignition coil negative terminal.
Turn the ignition switch to the ON position.
Tap the other end of the ignition coil ground wire jumper on a good grounding point (for example the battery negative terminal) and look for sparks at the spark plug that correspond to the frequency of your tapping of the ground wire.
If you have a good spark at the spark plug, the ignition coil is good.
If you don’t get a good spark, check for approximately 12 VDC from the coil positive terminal (black wire) to ground with the ignition switch in the ON position. You should also get approximately 12 VDC from the coil negative terminal (Green wire) to ground
B- Ignition Coil Resistance Check
In addition to the test above, you may elect to perform an ignition coil resistance check as confirmation of the coil’s condition.
- Check the ignition coil primary coil resistance by connecting an ohmmeter between the positive (Black wire) and negative (Green wire) terminals on the coil. The resistance should be 0.4 to 0.6 ohms.
- Check the ignition coil secondary coil resistance by connecting an ohmmeter between the coil output terminal and the ignition coil negative terminal. The resistance should be 5000 to 7200 ohms.
II- INSPECT AND TEST BALLAST RESISTOR
[photo: ballast resistor with two metal terminals, black wire, and metal mounting bracket]
| Procedures in checking Ballast Resistor |
|---|
| Steps/Procedure: 1. Prepare the supplies, materials, tools and equipment needed. 2. Disconnect primary wires connected to IG terminal or Fuses. 3. Disconnect primary wire connected to primary terminal of ignition coil. 4. Remove ballast resistor where it is connected. Note: Use ohmmeter to check the conditions of ballast resistor. 5. Connect the positive test probe of the ohmmeter on the terminal of the ballast resistor. 6. Connect the negative test probe of the ohmmeter on the other terminal of the ballast resistor. 7. Check for continuity and standard resistance, (no continuity (defective) standard resistance (5 ohms) 8. If the resistance is to high replace ballast resistor. |
III-CHECK HIGH TENSION CABLE RESISTANCE
[photo: two high-tension spark plug cables with boots and terminal ends]
The high-tension (HT) or secondary circuit carries high-voltage electricity. It runs from the secondary winding of the coil through the distributor to the plugs. Any of these can break down and cause ignition failure.
Ways in Testing High Tension Cables
A. Testing the high-tension cable leads
- Select the resistance position. Touch a probe to each end of the HT lead and read the resistance on the scale
- Detach each lead in turn
- Take off the plug cap if it is removable
- Measure the lead and work out its resistance, then measure actual resistance with an ohmmeter or multi-meter. If the reading is higher than the figure you worked out, or if it is more than 25,000 ohms, replace the whole set of leads. Some leads have a copper core with small resistance. Interference is suppressed by plug caps with 5,000 – 10,000 ohms’ resistance.
- Check the caps with an ohmmeter.
B. Testing for Voltage Leaks
Spark plug wires with bad insulation affect engine performance, especially during damp weather on rainy days. This test will check your wires’ insulation for voltage leaks.
- Connect one end of a jumper wire to a screwdriver metal shank
- Connect the other end of the jumper wire to a metal bracket or screw on the engine to ground the screwdriver.
- Set the emergency brakes on your vehicle, start the engine, and let it idle.
- Now, run the tip of the screwdriver along the length of each spark plug wire, about an inch away from the insulation.
- Pay attention to any spark or electric arc jumping off the insulation toward the tip of the screwdriver. Even if you can’t see the arc, you’ll hear a cracking sound as the spark jumps to the screwdriver, so pay attention to any sounds as well.
NOTE: If a spark or snapping sound during test were detected then replace the wires. However, if wires appear to have no voltage leak then go on to the next two tests.
C. Testing Spark Plug Wire Insulation
Having a spark plug wire with bad insulation may not be as bad as a wire with a broken conductor. Still, this is enough for your ignition system to cause all kinds of engine performance problems, especially during damp weather. This test will help you check your wires for voltage leaks.
- Connect one end of a jumper wire to a screwdriver shaft and the other end to a metal bracket or screw on the engine to ground the screwdriver.
- Set the emergency brakes on your vehicle, start the engine, and let it idle.
- Run the tip of the screwdriver along the length of each spark plug wire, about an inch away from the insulation. Pay attention to any spark or electric arc jumping off the insulation toward the tip of the screwdriver.
NOTE: If spark during test is detected then replace the wires.
D. Testing Spark Plug Wires Resistance
With this test, you’ll check the condition of the conductor that runs through the thick insulation of your spark plug wires. For this test, use a simple analog or digital ohmmeter.
- Set your meter to the ohms’ scale and to a setting that will let you read 50,000 ohms or above.
- Measure the length of the wire you want to read first using the tape measure, and make a note of the length in feet on a piece of paper.
- Then, turn on your ohmmeter and connect one lead to a metal connector inside the spark plug wire boot and the other lead to the other connector in the wire.
- Make a note of the wire’s resistance on the piece of paper as well.
- Lastly, you’ll want to multiply the length of the wire in feet by the ohms-per foot specification for your vehicle.
IV-TEST IGNITION SYSTEM WIRING INSTALLATION
[chart: wiring diagram; ignition system primary and secondary circuits, unnumbered. Labels printed: “IGNITION”, “START”, “BATTERY”, “IGNITION SWITCH”, “TERMINAL CONNECTOR”, “PRIMARY RESISTANCE WIRE”, “SPARK PLUG”, “QUICK DISCONNECT”, “RELAY”, “COIL”, “+”, “−”, “DISTRIBUTOR”. Legend: “PRIMARY CIRCUIT” (solid line), “SECONDARY CIRCUIT” (dashed line).]
A complete check of the ignition system includes the battery and cables, coil, distributor, primary and secondary wiring, and the spark plugs. This section describes the tests for all these units except the battery and the distributor.
Ways in Testing Ignition System Wiring Installation
A. Preliminary Checks
- Inspect the battery for corrosion due to acid and dirt. If necessary, remove the battery and cables and clean them with a baking soda solution. Be sure the cable connectors and the contacting surfaces on the battery, engine, and relay are clean. Tighten the cables securely upon installation.
- Corrosion. Inspect the wires for breaks and cracked insulation. Replace all defective wiring.
- Clean the inside of the distributor cap, and inspect it for cracks, burned contacts, or permanent carbon tracks. Remove dirt or corrosion from the sockets. Inspect the rotor for cracks or a burned tip. Replace the cap and/or rotor if they are defective.
B. Primary Circuit Resistance Test
- A complete test of the primary circuit consists of checking for excessive voltage drop from the battery to the coil and from the coil to ground.
- Excessive voltage drop in the primary circuit will lessen the secondary output of the ignition coil, resulting in hard starting and poor performance.
C. Test wiring installation
The following tests are made with the ignition switch on and the distributor points closed.
Connect the negative lead of a voltmeter to the battery terminal of the resistor and the positive lead to the positive terminal of the battery. If the voltage drop is 0.2 volts or less, the primary circuit from the battery to the coil is satisfactory.
[illustration: voltmeter wired between battery terminal of the resistor and battery positive terminal; labeled “VOLTMETER”; figure 1173-A]
If the voltage drop exceeds this limit, leave the positive lead of the voltmeter connected to the positive terminal of the battery and touch the voltmeter negative lead to the coil terminal of the ignition switch (If there is no change in the reading, the circuit is satisfactory. Next, touch the voltmeter negative lead to the battery terminal of the ignition switch. If the reading drops there is excessive resistance in the switch.
[illustration: voltmeter wired to coil terminal of the ignition switch; labeled “VOLTMETER”; figure 1175-A]
Check the primary resistor by connecting an ohmmeter across its terminals (Fig. 4). Disconnect the battery wire at the resistor to prevent damage to the ohmmeter. The specified resistance is 1.3-1.4 ohms. If the reading is over or under this limit replace the resistor.
[illustration: ohmmeter connected across the primary resistor terminals; labeled “OHMMETER”; figure 1174-A]
Check the resistance in the starting ignition circuit by connecting the voltmeter positive lead to the positive terminal of the battery and the negative lead to the battery terminal of the coil. Disconnect the high tension lead at the coil and Crank the engine while observing the voltage drop. It should not exceed 0.1 volt. If the voltage drop is excessive, clean and tighten the terminals or replace wiring as necessary.
[illustration: voltmeter connected between battery positive terminal and battery terminal of the coil during cranking; labeled “VOLTMETER”; figure 1172-A]
V-DISTRIBUTOR CAP AND ROTOR INSPECTION
[illustration: distributor cap and rotor]
- Grasp the distributor cap and attempt to move it back and forth. If it moves easily, the retaining screws are not properly engaged or the distributor cap gasket is compressed and needs to be replaced.
- Remove the distributor cap.
- Inspect the distributor cap for the following and replace as necessary:
a. Cracks
b. Carbon tracking
c. Moisture buildup on inside of cap
d. Debris
e. Worn rotor button
f. Pitted, worn, or charred terminals - Inspect the rotor for charring or pitting and replace if necessary.
- Check the rotor retaining screw is in place. These screws have a tendency to fall out causing the rotor to become misaligned.
- Ensure the dust cover is securely in place behind the rotor.
This dust cover is important because it keeps debris from the belt housing area from getting into the distributor cap and causing poor or non-existent spark.
VI-CHECKING DWELL ANGLE AND RPM
[illustration: breaker points diagram and tachometer gauge marked x1000 RPM]
Dwell Angle pertains to the amount of rotation through which breaker points remain closed to energize the ignition primary coil.
RPM or Revolutions per Minute is the measures of how many times the engine’s crankshaft makes one full rotation every minute, and along with it, how many times each piston goes up and down in its cylinder
Measuring The Dwell Angle
a. Prepare the supplies, materials, tools and equipment needed. b. If you have just fitted new contact-breaker points, set them to approximately the right gap with a feeler gauge. c. With the dwell meter connected, start the engine and let it settle to a smooth tick over. If it will not tick over steadily, check the cause(s) and rectify any faults. d. The meter reading should stay steady at a steady engine speed. If it does not, increase the idling speed slightly until it does (See Preparing for carburetor adjustment). e. Compare the steady reading on the appropriate scale with the desired dwell angle for your make of car. f. If it is too high, the contact-breaker gap is too small. If it is too low, the gap is too wide. g. Before you switch off the engine to adjust the gap, make the following checks. First ask a helper to press the accelerator to increase the engine speed slowly to about 1,000 rpm, then let it drop back to idling speed while you note the reading. h. The angle should remain about the same, with no more than two or three degrees’ deviation. i. Secondly, increase the engine speed quickly to about 1,500 rpm, then let it drop back to idling speed while you again note the reading.
j. The angle should again remain the same, fluctuating by no more than two or three degrees. k. Carry out these two tests several times so that you can take an average of any differences in the readings. l. If the reading constantly fluctuates more than two or three degrees, the distributor-shaft bearing or advance-retard plate may be worn, or the cam itself damaged. Fit a new distributor. m. Switch off the engine before making any adjustments necessary to the contact breaker gap.
Adjusting Contact Point Gap
Procedure in Adjusting contact point clearance
Steps/Procedure:
Procedures in adjusting contact point when the distributor assembly is install to engine.
- Prepare the supplies, materials, tools and equipment needed.
- Turn the engine to correct direction of rotation by the use of correct size box or socket wrench that fit to crankshaft pulley fixing bolt.
- Position the contact point to be set in highest portion of the cam lobe in distributor shaft.
- Use proper type, and size of screw driver prior to the screw head kind.
- Loosen the slightly lock and adjusting screw then, insert the feller gauge with correct size of clearance, follow what is in the manual.
- Tighten first the adjusting screw with two working screw drivers for it to locks then, lastly tighten the lock screw. If possible, check it thoroughly again by retightening the adjuster and locker screws.
- Test run then, proceed to next operation sheet.
[illustration: distributor assembly with contact points and screws]
Procedure in adjusting contact point when distributor assembly remove from engine.
- Prepare the supplies, materials, tools and equipment needed.
- Position correctly and firmly the distributor assembly in the Bench vise.
- Position the contact point to be set on the highest part camlobe in distributor shaft.
- Used proper type, and size of screw driver prior to the screw head kind.
- Loosen slightly lock and adjusting screw then, insert the feller gauge with correct size of clearance, follow what state in the manual.
- Tighten first the adjusting screw with two working screw drivers for it, to locks then, lastly tighten the lock screw. If possible, check it thoroughly again by retightening the adjuster and locker screws.
- Set engine correctly then install the distributor assembly, time it properly, see the steps of initial ignition timing.
- Test run, then check if dwell angles is within the specified value, by the used of the dwell meter, follow the dwell of 4 cylinders is 51º (50º – 52º)
POINT GAP ADJUSTMENT (W/O IGNITER)
- If the points are excessively burnt or fitted, replace the breaker points.
- Adjust point gap.
Point gap 0.45 mm (0.18 in)
[illustration: breaker points with feeler gauge]
If dwell angle below specified degrees’ point gap is too big. But if the dwell angle above specified degrees’ point gap is too small, readjust the point clearance to make it with the correct dwell angle, by the used of dwell meter for dwell angle while for the R.P.M used tachometer for setting the correct idling of engine.
A. SAFETY MEASURES OR PROCEDURES IN ADJUSTING CONTACT POINT.
[illustration: cam lobe and breaker points showing dwell angle; labels: 80, DWELL ANGLE, GAP WHEN POINTS OPEN, POINTS CLOSE, POINTS OPEN, DWELL ANGLE]
- When testing a vehicle, never short plug lead to the dipstick, cam/rocker arm cover, battery or other components, which may not be directly earthed. This can cause an explosion of oil fumes or hydrogen.
- Beware of the danger from rotating components of ignition system.
- Never bend movable point arm with your hand.
- Do not use the car, if the contact breaker point is not exactly adjusted to the manufacturer specifications.
- Do not install local contact point to the car of your customers and replacement of part be checked thoroughly, to avoid any trouble?
- Use the proper screw driver for right head of bolt screw.
- In replacing contact points do the same with the condenser or capacitor used the required capacitance or farad.
Note: With the contact points closed, the magnetic field builds up in the coil. As the points open, the magnetic field collapses and voltage is sent to the spark plugs. The part of the distributor assembly that is responsible in opening and closing the contact points is the camlobe.
VII-CHECK AND ADJUST IGNITION TIMING
[photo: timing light being used on an engine with the battery visible]
Ignition timing
Ignition timing is the measurement, in degrees of crankshaft rotation, of the point at which the spark plugs fire in each of the cylinders. It is measured in degrees before or after Top Dead Center (TDC) of the compression stroke.
Procedure in performing ignition timing
Procedure in performing the setting base ignition timing.
Prepare the supplies, materials, tools and equipment needed.
NOTE: Use a timing light to check the timing. Follow these steps for ignition timing adjustment.
Connect the timing light, and start the engine.
The engine must be idling at the manufacturer’s recommended rpm end all other timing procedures must be followed.
Aim the timing light marks at the timing indicator, and observe the timing marks. Compare this reading to the manufacturer’s specifications. For example, if the specification reads 10 degrees before top dead center and the reading found is 3 degrees before top dead center, the timing is retarded or off by 7 degrees.
If the timing mark is not at the specified location, rotate the distributor until the mark is at the specified location.
Tighten the distributor hold-down bolt to the specified torque, and recheck the timing mark position.
Connect the vacuum advance hose and any other connectors, hoses, or components that were disconnected for the timing procedure.
Road testing in the highways.
Interpretations of Timing Marks
Timing marks illuminated by a timing light and showing 10 degrees BTDC.
[illustration: timing light aimed at timing marks; label: TIMING MARKS ALIGNED AT 10]
Timing marks at 3 degrees BTDC.
[illustration: timing light aimed at timing marks; label: TIMING MARKS ALIGNED AT 3]
The timing light flashes every time the number 1 sparks plug fires.
[illustration: timing light with trigger and timing advance meter aimed at crankshaft timing mark; labels: CRANKSHAFT TIMING MARK, TIMING LIGHT, TIMING ADVANCE METER, TRIGGER]
SAFETY MEASURES IN PERFORMING IGNITION TIMING
- Do not puncture cables or nipples with test probes. This will ruin the cables of ignition timing light.
- Do not point laser flashes of stroboscopic light to anybody due to the strong ultraviolet rays, especially to eyes.
- Keep off your hands to the rotating parts of the engine in performing the test.
- Remove necklace, rings, and watches or wear suitable working uniform in conducting the ignition timing with stroboscopic light.
- See to it that the test probes of timing light and other connections are tight, set and connected correctly.
- Always use the manual as your guide for the adjustment.
- Be sure your concentration is given fully to the job in performing gasoline ignition timing.
VIII-ELECTRONIC IGNITION TROUBLESHOOTING PROCEDURE
Steps:
- Turn the ignition on (engine off) and, using either a voltmeter or a test light, test for battery voltage available at the positive terminal of the ignition coil.
- If the voltage is not available, check for an open circuit at the ignition switch or wiring.
What’s More
Directions: Match the picture from column A to column B. Write your answers in the given answer sheet. Answers may be repeated.
| Column A | Column B |
|---|---|
| 1. [illustration: hand holding an ignition coil wire and a lead] | A. Ignition Coil Testing |
| 2. [illustration: distributor with a wire being removed, held by hand] | B. Spark Plug Checking |
| 3. [illustration: distributor cap, top view] | C. Adjusting Timing |
| 4. [illustration: distributor with contact points, adjusted by hand] | D. Contact Point Adjusting |
| 5. [illustration: ignition timing diagram; printed labels: 4° BTDC at 600 rpm, 360°, 180°, TDC, 4° Ignition Timing mark TDC] | E. Ballast Resistor Checking |
| 6. [illustration: hand working at the distributor cap area] | F. Distributor Cap Checking/ Inspecting |
[transcriber’s note: table continued from the previous page]
| Column A | Column B |
|---|---|
| 7. [illustration: distributor points diagram with a screwdriver] | G. Idle adjustment |
| 8. [illustration: distributor with printed caption: ADJUST DWELL ANGLE SETTING OR POINT OPENING; Fig. 8-35 Setting the Distributor Points; Courtesy of General Motors of Canada Limited] | H. Dwell Angle |
| 9. [illustration: ignition switch key positions with a hand turning the key] | I. Ignition Switch Checking |
| 10. [illustration: two digital multimeters with leads connected to an ignition coil; displayed readings 0023 and 113.1 [?]; printed label: IGNITION COIL] | J. High Tension Wire Testing |
What I Have Learned
In a vehicle, ignition system plays an important role specifically in a vehicle equipped with gasoline engines for a vehicle won’t start without it, and also proper maintenance must be applied to its components to ensure its functionality.
Directions: As a child, what are your roles that makes you important in your family and how could you maintain that roles? Write your answers in the given answer sheet.
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What I Can Do
Directions: Supposed you have a vehicle that won’t start but the battery is in full state of charge. Explain the remedies or procedures that you must apply? Write your answer in the answer sheet.
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Post-Assessment
Multiple choice
Direction: Choose the LETTER of the best answer. Write your answer in the answer sheet.
1. The part of the distributor assembly that opens and closes the contact point?
- A. The camshaft
- C. The distributor shaft
- B. The distributor cam/camlobe
- D. A spring
2. A system that is responsible in delivering an electric spark in the engine combustion chamber, at exactly the right time, which will ignite the mixture of petrol and air.
- A. Charging system
- C. Lighting System
- B. Ignition system
- D. Starting system
3. When checking ignition timing, the timing light flashes every time the spark plug number ______________ fires.
- A. 1
- B. 2
- C.3
- D. 4
4. When checking the ignition coil primary resistance using ohmmeter, the resistance should be___________ ohms?
- A. 0.4 to 0.6
- B. 0.6 to 0.8
- C. 0.8 to 0.10
- D. 0.10 to 0.12
5. When checking the ignition coil secondary resistance by using an ohmmeter the resistance should be ____________ ohms?
- A. 1000 to 2200
- B. 3000 to 4500
- C. 4000 to 5000
- D. 5000 to 7200
6. The two places the ignition timing marks can be located?
- A. Camshaft and crankshaft sprocket
- C. Harmonic balancer and flywheel
- B. Distributor and points
- D. Water pump pulley and fan belt
7. The contact points position where magnetic field builds up in the coil.
- A. Close
- B. Open
- C. Both
- D. None of the above
8. The contact points position where the magnetic field collapses and voltage is sent to the spark plugs.
- A. Close
- B. Open
- C. Both
- D. None of the above
9. When checking ballast resistor for resistance, resistance should be?
- A. 5 ohms
- B. 6 ohms
- C. 7 ohms
- D. 8 ohms
10. When adjusting contact point clearance, the gap should be?
- A. 0.6 in
- B. 0.8 in
- C. 0.10 in
- D. 0.18 in
11. It measures how many times the engine’s crankshaft makes one full rotation every minute, and along with it, how many times each piston goes up and down in its cylinder?
- A. RPM
- B. Speedometer
- C. Tachometer
- D. all of the above
12. It pertains to the amount of rotation through which breaker points remain closed to energize the ignition primary coil.
- A. Dwell angle
- B. Dwell
- C. Angle
- D. None of the following
13. It is the measurement, in degrees of crankshaft rotation, of the point at which the spark plugs fire in each of the cylinders. It is measured in degrees before or after Top Dead Center (TDC) of the compression stroke.
- A. Ignition timing
- B. Ignition system
- C. Timing
- D. RPM
14. The tool that is used in checking timing?
- A. Ignition timing
- B. Ignition system
- C. Timing light
- D. RPM
15. If the timing mark is not at the specified location, rotate the __________ until the mark is at the specified location.
- A. Distributor
- B. Ignition Coil
- C. Ignition Switch
- D. all of the above
Additional Activity
Direction: Enumerate the procedures in performing Ignition Timing. Write your answers in the answer sheet.
Answer Key
What I Know
- A
- A
- B
- C
- A
- A
- A
- C
- A
- A
- A
- B
- B
- B
- A
What’s in
[illustration: ignition system components diagram]
What’s New
The pictures are all about Ignition System Components maintenance.
What’s More
- J
- A
- F
- E
- C
- C
- D
- D
- H
- A
What I Have Learned
Answers may vary
What I Can Do
Answers may vary
Post Assessment
- B
- B
- A
- A
- D
- A
- A
- B
- A
- D
- A
- A
- A
- C
- A
Additional Activity
- Prepare the supplies, materials, tools and equipment needed.
NOTE: Use a timing light to check the timing. Follow these steps for ignition timing adjustment.
Connect the timing light, and start the engine.
The engine must be idling at the manufacturer’s recommended rpm end all other timing procedures must be followed.
Aim the timing light marks at the timing indicator, and observe the timing marks. Compare this reading to the manufacturer’s specifications. For example, if the specification reads 10 degrees before top dead center and the reading found is 3 degrees before top dead center, the timing is retarded or off by 7 degrees.
If the timing mark is not at the specified location, rotate the distributor until the mark is at the specified location.
Tighten the distributor hold-down bolt to the specified torque, and recheck the timing mark position.
Connect the vacuum advance hose and any other connectors, hoses, or components that were disconnected for the timing procedure.
Road testing in the highways.
References
Auto Mechanics Theory and Service by deKryger et.al, The Ignition System, South-Western Publishing Co.USA 1986
Auto Mechanics Theory and Service by deKryger et.al, Ignition System Service, South-Western Publishing Co.USA 1986
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