When searching for the cause of trouble, the first thing to do is to concentrate on the symptoms of the trouble. If the symptoms are not clearly understood, a long period of time will be required to correct the problem.
In order to shorten the time required to find the causes of trouble, it is necessary to inspect the system in the order of the most likely causes of trouble first, working down to the less likely causes. If no trouble can be found in the ignition system.it is necessary to inspect other systems (the fuel system and the engine proper.)
TROUBLESHOOTING PROCEDURES
If there is trouble in the ignition system, the problem could be because the engine is out of tune due
1) misfiring (failure of the air-fuel mixture to burn) or 2) faulty ignition timing.
There are of course other possible causes, but these are the most common ones. In order to determine which of these possibilities is the most likely, an investigation must be conducted. The following table and flow chart indicate methods for searching out some representative troubles.
For details on adjustments, repair and other related information, refer to the repair manual for the relevant model.
Symptoms of Trouble Cause of Trouble
1) * Engine will not start/hard to start (cranks OK) The First likely cause is misfiring. The next
* Rough idle or stalls thing to consider
* Engine hesitates / poor acceleration is the ignition timing.
* Poor fuel economy
2) * Muffler Explosion (afterfire) all the time Items indicating that
* Engine backfires the problem is
* Engine overheats ignition timing.
HOW TO TROUBLESHOOT AN ALTERNATOR
Car Will Not Start
- Dead battery: Check battery cells, alternator belt tension and alternator output
- Loose or corroded battery connections: Check all charging system connections
- Ignition circuit or switch malfunction: Check and replace as necessary
- Loose or worn alternator drive belt: Check alternator drive tension and condition
- Loose alternator wiring connections: Check all charging system connections
- Short in alternator light wiring
- Defective alternator stator or diodes
- Defective regulator
- Blown fuse
- Defective alternator
- Defective indicator light bulb or socket
- Short in alternator wiring
- Defective rectifier bridge
- Defective alternator wiring
- Defective regulator
- Defective battery: Check and replace as necessary
- Loose or worn drive belt: Check alternator drive belt tension and condition.
- Defective wiring: Check all wires and wire connections
- Defective alternator or regulator
- Defective ammeter, or improper ammeter wiring connection
- Loose drive pulley: Tighten drive pulley attaching nut
- Loose mounting bolts: Tighten all alternator mounting bolts
- Worn or dirty bearings
- Defective diodes or stator
- Loose or worn drive belt: Check alternator drive belt tension and condition.
- Loose or corroded battery connections: Check all charging system connections
- Loose alternator connections: Check all charging system connections
- Defective alternator or battery
- Add-on electrical accessories exceeding alternator capacity: Install larger alternator
- Defective battery: Check alternator output and repair as necessary
- Defective alternator
- Excessive alternator voltage: Check alternator output and repair as necessary
Check the Battery If it is Condition or Not
A.Before beginning the battery test, make sure that the batteries are 95% - 100% charged. Use a battery charger, if necessary.
B.Shut off all electrical accessories in the vehicle and run the engine at approximately 1000 - 1200 RPM.
C.Connect a DC voltmeter to the battery terminals and measure the voltage. Compare the values to those specified by the battery manufacturer. If the voltage is above the manufacturers specification, an OVERCHARGE condition exists. If the measured voltage is below the manufacturers specification, an UNDERCHARGE condition exists.
Overcharge and Discharge Test
Battery overcharge and undercharge conditions each require a specific set of procedures to be performed. The following diagram shows the order in which the procedures are performed. A more detailed description of these procedures follows.
Battery overcharge and undercharge conditions each require a specific set of procedures to be performed. The following diagram shows the order in which the procedures are performed. A more detailed description of these procedures follows.
 |
| Information of Battery Inspection |
Battery Overcharge Testing
Overcharge batteries (output over 14.2 volts for most 12-volt systems, or over 28.4 volts for 24-volt systems) can be caused by a defective battery (usually indicated by excessive gassing), a defective diode trio, or a defective or improperly adjusted voltage regulator.
After testing the batteries for shorts, perform the "Diode Trio Test" procedure in this bulletin, followed by "Voltage Regulator Adjustment" procedure, if necessary.
Battery Undercharge Testing
To avoid unnecessary work, always check for loose belts, a defective battery, and damaged or corroded wires and connections first. If the battery, belts, and wiring are in good working condition, perform the "Diode Trio Test" procedure. If the diode trio is in good shape, perform the "Full Field Test."
Diode Trio Test (on units equipped with a diode trio)
1. Remove the diode trio from the alternator.
2. Connect the negative (-) ohmmeter test lead to the diode trio lead terminal as indicated in the diagram. Connect the positive (+) test lead to each of the three copper contact pads, one at a time. Observe the resistance at each contact pad and write down the resistance for each contact for later reference.
3. Reverse the leads so the positive (+) test lead is connected to the diode trio lead terminal and the negative (-) test lead connects to the contact pads. Again observe the resistance at each of the contact pads and record the results for each contact.
NOTE: The diode trio is OK when a LOW resistance reading is observed in one direction and a HIGH resistance is observed in the other direction. Occasionally the diode trio malfunctions under operating conditions only.
4. If the diode trio is malfunctioning, replace it. Otherwise, reinstall the diode trio on the alternator.
2. Connect the negative (-) ohmmeter test lead to the diode trio lead terminal as indicated in the diagram. Connect the positive (+) test lead to each of the three copper contact pads, one at a time. Observe the resistance at each contact pad and write down the resistance for each contact for later reference.
3. Reverse the leads so the positive (+) test lead is connected to the diode trio lead terminal and the negative (-) test lead connects to the contact pads. Again observe the resistance at each of the contact pads and record the results for each contact.
NOTE: The diode trio is OK when a LOW resistance reading is observed in one direction and a HIGH resistance is observed in the other direction. Occasionally the diode trio malfunctions under operating conditions only.
4. If the diode trio is malfunctioning, replace it. Otherwise, reinstall the diode trio on the alternator.
Field Testing
1. Run engine at approximately 1000 RPM with all electrical accessories "OFF". Measure the output voltage across the alternator terminals and write it down for later reference.
NOTE: Use a digital voltmeter with .01-volt reading capabilities or any good voltmeter.
2. Attach a short jumper to a 2" piece of stiff wire (a paper clip is suitable).
3. Connect the other end of the jumper to the negative (-) alternator output terminal and insert the wire in the FULL FIELD ACCESS HOLE (see photo). Hold the wire firmly against the brush terminal inside the housing. (Also flashes Field.)
4. With the jumper in place, connect a voltmeter across the alternator terminals and run the engine at approximately 1000 RPM. Compare this voltage reading with the voltage reading obtained in Step 1.
5. With the jumper still hooked up and the wire in the FULL FIELD ACCESS HOLE, connect an AC voltmeter across terminals 1&2, 1&3, and 2&3, and note the voltages. If all of the voltages are approximately the same, they are considered "balanced."
6. Remove the jumper and wire from the alternator. If the voltage in Step 4 is higher than the voltage in Step 1, and the voltages measured in Step 5 are balanced, the stator and alternator are OK and you should proceed to the "Voltage Regulator Adjustment" procedure
If the voltage in Step 4 is higher than the voltage in Step 1, and the voltages measured in Step 5 are not balanced, the alternator stator or rectifier(s) defective. Repair or replace alternator.
If the voltage in Step 4 is lower or equal to the voltage in Step 1, and the voltages measured in Step 5 are balanced, the alternator is defective. Replace alternator.
If the voltage in Step 4 is lower or equal to the voltage in Step1, and the voltages measured in Step 5 are not balanced, alternator stator or rectifier(s) are defective. Replace the alternator.
NOTE: Use a digital voltmeter with .01-volt reading capabilities or any good voltmeter.
2. Attach a short jumper to a 2" piece of stiff wire (a paper clip is suitable).
3. Connect the other end of the jumper to the negative (-) alternator output terminal and insert the wire in the FULL FIELD ACCESS HOLE (see photo). Hold the wire firmly against the brush terminal inside the housing. (Also flashes Field.)
4. With the jumper in place, connect a voltmeter across the alternator terminals and run the engine at approximately 1000 RPM. Compare this voltage reading with the voltage reading obtained in Step 1.
5. With the jumper still hooked up and the wire in the FULL FIELD ACCESS HOLE, connect an AC voltmeter across terminals 1&2, 1&3, and 2&3, and note the voltages. If all of the voltages are approximately the same, they are considered "balanced."
6. Remove the jumper and wire from the alternator. If the voltage in Step 4 is higher than the voltage in Step 1, and the voltages measured in Step 5 are balanced, the stator and alternator are OK and you should proceed to the "Voltage Regulator Adjustment" procedure
If the voltage in Step 4 is higher than the voltage in Step 1, and the voltages measured in Step 5 are not balanced, the alternator stator or rectifier(s) defective. Repair or replace alternator.
If the voltage in Step 4 is lower or equal to the voltage in Step 1, and the voltages measured in Step 5 are balanced, the alternator is defective. Replace alternator.
If the voltage in Step 4 is lower or equal to the voltage in Step1, and the voltages measured in Step 5 are not balanced, alternator stator or rectifier(s) are defective. Replace the alternator.
Adjust Voltage Regulator
Leece-Neville alternators are equipped with one of two regulators. The Fully Adjustable Regulator has a flat cover plate. The Three Step Regulator has a finned, curved cover plate. Use the following test procedure that is appropriate for you regulator type.
Fully Adjustable Regulator
NOTE: Battery must be at least 95% charged prior to this procedure. Also make sure wire connections and belt tension are OK.
1. Shut off all electrical accessories and run the engine at approximately 1000 RPM.
2. Connect a voltmeter to the alternator outputs.
3. Remove the plastic screw from the regulator (see photo) and insert a small screwdriver in the hole. Engage the screwdriver blade in the slotted adjustment screw inside the regulator.
CAUTION: The adjustment potentiometer screw has high and low stops. DO NOT exert excessive pressure on the screwdriver or you may damage the regulator.
4. Turn the screwdriver clockwise to raise the voltage, counterclockwise to lower the voltage. Set the voltage between 14.0 and 14.2 volts (28.0 to 28.4 volts for 24-volt units).
CAUTION: DO NOT force the screwdriver past the set stops at either end of the adjustment range to avoid regulator damage.
5. Remove the screwdriver and voltmeter and install the plastic screw in the adjustment screw access hole.
3 Procedure of Adjusting Voltage Regulator
1. Stop the engine and disconnect the battery ground cable.
2. Remove the #10-32 nuts and lockwasher from the regulator terminal and disconnect the diode trio lead (if alternator is equipped with a diode trio).
3. Remove the four screws from the regulator cover. Lift the regulator out of the housing and move it out of the way as far as the leads will permit. Inspect the two regulator brush contact pads (see photo). If dirt or corrosion is noted, clean the pads with #600 or finer sandpaper.
NOTE: In some cases, dirty or corroded contact pads can cause a low charge condition and voltage adjustment may not be necessary.
4. Inspect and reinstall the brushes.
HOW TO TROUBLESHOOT AN IGNITION SYSTEM
If you've come to this procedure, you probably suspect that you have a no spark condition. If so, you should have already verified that you actually have a no spark condition by performing the initial "no spark" test described in TS-01, Troubleshooting - Engine Will Not Start.
There are many different ways to go about testing for a no spark condition. The only problem in determining the ultimate cause of a no spark condition is that if the condition is caused by a problem with the DME computer, there's really no way to conclusively test the DME. The same is true with a no fuel condition. So, what we have to do is determine, as best we can, whether the DME is getting power and whether it's getting all of the correct input signals it requires to run the engine. If we get all of the proper inputs and the DME is still not providing the desired output (i.e. spark from the ignition coil or running the fuel pump), we make the assumption that the DME computer is bad and we replace it.
One of the best ways to test the DME computer is to swap it for a known good DME computer. However, most of us don't have the luxury of keeping a spare DME computer on hand. However, if you suspect that starting or running problem may be due to a bad DME computer, try to borrow a computer to test your car before running out and buying a DME.
Tools
* Mulitmeter
* Test lead jumpers
No Spark Condition
Possible Cause Comments
Bad Distributor Cap / Rotor Inspect distributor cap and rotor per procedure below.
Bad Ignition Coil Check coil using Ignition Coil Test procedure below. Bad Engine Cranking / Running Signal to DME Check engine cranking / running signals using FUEL-16.
Faulty DME computer Check DME computer using FUEL-16.
Distributor Cap and Rotor Inspection
- 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.
- Using IGN-01, remove the distributor cap.
- Inspect the distributor cap for the following and replace as necessary:
- Cracks
- Carbon tracking
- Moisture buildup on inside of cap
- Debris
- Worn rotor button
- 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.
- Disconnect the ignition coil output wire at the distributor cap.
- Connect a spark plug to the end of the ignition coil output wire which you just disconnected.
- Connect a ground wire to the threaded portion of the spark plug.
- Disconnect the ignition coil ground wire from the negative terminal on the coil (Green Wire).
- Connect one end of a ground wire 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 an 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
Before trouble shooting or 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.
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
- Fuel lines leaking or clogged: Tighten fitting, remove restriction
- Initial timing incorrect: Reset ignition timing
- Centrifugal advance malfunction: Repair distributor advance
- Defective spark plugs or wiring: Replace plugs or plug wiring
- 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
Firing Voltage Lines are the Same, but Abnormally High
- Retarded ignition timing: Reset ignition timing
- Fuel mixture too lean: Readjust carburetor
- 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
- Fuel mixture too rich: Readjust carburetor
- 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
- Carburetor idle mixture not balanced: Readjust carburetor
- 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
- Curb idle mixture not balanced: Readjust carburetor
- 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
- Corroded spark plugs: Replace spark plugs
- 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
A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed air and fuel by means of an electric spark. Spark plugs have an insulated center electrode which is connected by a heavily insulated wire to an ignition coil or magneto circuit on the outside, forming, with a grounded terminal on the base of the plug, a spark gap inside the cylinder.
As the current of electrons surges across the gap of the spark plug, it raises the temperature of the spark channel to 60,000 K. The intense heat in the spark channel causes the ionized gas mixed with air to expand very quickly, like a small explosion however more known as a combustion. This is the "click" heard when observing a spark, similar to lightning and thunder. A new type of plug called a pulse plug released in 2007 incorporates a peaking capacitor into the plug itself that releases all its contents into the plug gap giving a much more intense spark.
The heat and pressure force the gases to react with each other, and at the end of the spark event there should be a small ball of fire in the spark gap as the gases burn on their own. The size of this fireball or kernel depends on the exact composition of the mixture between the electrodes and the level of combustion chamber turbulence at the time of the spark. A small kernel will make the engine run as though the ignition timing was retarded, and a large one as though the timing was advanced. Wikipedia:Spark Plugs
The general trouble shooting information lists common vehicle symptons with possible solutions and is not for any particular vehicle make and model. For repair info specifically for your make and model please view the main directory.
Normal Spark Plug Condition
- Light Tan or Gray deposits
- Electrode not burned or fouled
- Gap tolerance not changed
- Overrich air and fuel mixture: Adjust air and fuel mixture
- Faulty choke: Replace choke assembly
- 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
- Worn rings and pistons: Install new rings and pistons
- Excessive cylinder wear: Rebore or replace block
- Excessive valve guide clearance: Worn or loose bearing
- Deposits in combustion chamber becoming fused to electrode: Clean combustion chamber of deposits
- Engine overheating: Check cooling system
- Wrong type of fuel: Replace with correct fuel
- Loose spark plugs: Re tighten spark plugs
- Over-advanced ignition timing: Reset ignition timing see
- Incorrect type of fuel: Replace with correct fuel
- Incorrect ignition timing: Reset ignition timing
- Burned valves: Replace valves
- Engine Overheating: Check cooling system
- Wrong type of spark plug, too hot: Replace with correct spark plug
- Severe detonation: Check for over-advanced timing or combustion
- Improper gapping procedure: Re-gap spark plugs
- Additives in unleaded fuel Try different fuel brand
- Blown head gasket or cracked head Repair or replace Cylinder head or head gasket
HOW TO TROUBLESHOOT ON STARTING SYSTEM
The general trouble shooting information lists common vehicle symptoms with possible solutions and is not for any particular vehicle make and model. For repair info specifically for your make and model please view the main directory. This troubleshooting guide pertains to any starter issues for example: "I hear a click but my car doesn't start, I crank my engine but it cranks real slowly and does not start, etc."
Starter does not work
- Dead battery or bad connections between starter and battery: Check battery charge and all wires and connections to starter
- Ignition switch faulty or miss adjusted: Adjust or replace ignition switch
- Open circuit between starter switch ignition terminal on starter relay: Check and repair wires and connections as necessary
- Starter relay or starter defective
- Open solenoid pull-in wire
- Weak battery or dead cell: Charge or replace battery as necessary
- Loose or corroded battery connections: Check that battery connections are clean and tighten
- Internal ground in starter windings
- Grounded starter fields
- Armature rubbing on pole
- Starter clutch slipping
- Broken clutch housing
- Pinion shaft rusted or dry
- Engine basic timing incorrect
- Broken teeth on engine flywheel: Replace flywheel and check for starter pinion gear damage
- Weak drive assembly thrust spring
- Weak hold-in coil
- Defective point assembly
- Poor point assembly ground
- Defective pull-in coil: Replace starter solenoid
- Dead battery: Charge or replace battery as necessary
- Faulty wiring: Check all wiring and connections leading to relay
- Neutral safety switch faulty: Replace neutral safety switch
- Starter relay faulty: Replace starter relay
- Starter motor loose on mountings: Tighten starter attach bolts
- Worn drive end bushing
- Damaged engine flywheel teeth: Replace flywheel and starter pinion gear for damage
- Drive yolk return spring broken or missing: Replace return spring
- Faulty ignition switch: Replace ignition switch
- Insufficient clearance between winding leads to solenoid terminal and main contact in solenoid: Replace starter solenoid
- Starter clutch not disengaging: Replace starter clutch
- Ignition starter switch: Replace ignition switch contacts sticking
- 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
- 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
- Worn brushes or weak brush springs: Replace brushes or brush springs as necessary
- Distance too great between starter pinion and flywheel: Align starter or check that correct starter and flywheel are being used
- Distance too small between starter pinion and flywheel: Flywheel runout contributes to the intermittent nature
No comments:
Post a Comment