Ignition System

Problem

Engine cranks normally but fails to start.

Cause

No voltage to ignition system. Ignition module lead open, grounded, loose or corroded. Primary connections not tight. Ignition coil open or shorted. Defective reluctor or pick up coil. The ignition module is defective. Defective distributor cap or rotor. Faulty  fuel system. Engine faulty.

Solution

Check battery, ignition switch, wiring. Repair as needed. Clean, seat connectors. Test coil, replace if defective. Replace reluctor or pick up coil. Replace ignition module. Replace distributor cap or rotor. Check fuel system. Check engine and service if required.

Problem
Engine backfires but fails to start.

Cause
Incorrect timing. Moisture in distributor cap. Voltage leak across the cap. Secondary cables not connected in firing order. Cross firing between secondary cables.

Solution

Set timing. Dry the cap. Replace the cap. Reconnect secondary cables correctly. Replace defective cables.

Problem
Engine runs but misses.

Cause
Spark plugs fouled or faulty. Cap or rotor faulty. Secondary cables defective. Defective ignition coil. Bad connections. High voltage leaks. Advance mechanism defective. Defective fuel system. Mechanical engine problems.

Solution
Clean, regap or replace spark plugs. Replace cap or rotor. Replace secondary cables. Replace ignition coil. Clean or tighten bad connections. Check cap, rotor or secondary cables. Check, repair or replace advance mechanism. Check fuel system. Repair or service engine.

Problem
Engine overheats.

Cause
Late timing. Lack of coolant or other trouble in cooling system. Late valve timing or other.

Solution
Set ignition timing. Check camshaft timing, tappet clearance, adjust if needed.

Problem
Engine springs spark knock.

Cause
Incorrect timing. Wrong fuel used. Defective advance mechanism. Carbon build up in cylinders.

Solution
Set ignition timing. Use correct fuel as recommended. Repair or replace advance mechanism. Service engine.

Problem
Spark plug defective.

Cause
Cracked insulator. Carbon filled spark plug. Busted spark plug.

Solution
Set ignition timing. Clean spark plug. Install new spark plug.

Problem

Engine runs on or diesels.

Cause

Idle solenoid out of adjustment or fuel shut off faulty. Hot spots in combustion chamber. Engine overheating. Advance timing.

Solution

Adjust or replace solenoid. Service engine. Set ignition timing.

Ignition System Service

Checking and testing of the ignition coil primary winding and secondary winding resistance. By the use of multi tester, test the resistance between positive and negative terminal of ignition coil. The test must have 1.3 to 1.6 ohms resistance. Test secondary winding resistance between positive terminal and center tower terminal. It must have 10.7 to 14.5 kilo ohms.

Check power source line using the voltmeter, check voltage at the positive terminal. Turn the ignition switch to on position, connect the positive probe of voltmeter to the negative side of terminal to engine body or ground. Approximately 12 volts power supply.

Check primary circuit by checking lose connection in the primary circuit. Battery, ignition switch, ignition coil, condenser, contact point. Grounded circuit can lead to malfunctioning of ignition system and produce spark. Check the open wire.

Check the contact point for corrosion and burns produced by the electric arcing when contact point close.

Check the distributor cap from corrosion, breaks and oil. Carbon contact at the cap center tower breaks that it cannot contact with the rotor.

Check the high tension cable from cracks, scratches, burns and open insulation. This can cause spark when it touches engine body. Test the high tension cable resistance, It must less than 25 kilo ohms.

Check spark plug by conducting spark test. Inspect spark plug gap. The gap ranges from 0.8 mm to 1.1 mm. Clean the spark plug tip. Inspect porcelain insulation for cracks.

Inspect rotor and distributor assembly. Check rotor tip from corrosion or bend. Check also distributor shaft for play. Condenser wire and contact point wire must not be grounded at distributor body.