- Overview
- Tools Required / Recommended
- 6 volt / 12 volt / 24 volt Systems
- The Basic System
- Step by Step Diagnosis (trouble shooting)
- Oddities - weird things I have found
- What to watch out for
This web page is dedicated to the Willys enthusiasts that have delved into the ignition system to get their pride and joy running. It is my sincere hope that this provided some benefit in that endeavor.
No spark from your L134 ignition system? This question is repeated over and over again. Here is a comprehensive check list when you have run out of things to check
This article will step you through a through diagnosis of the ignition system for a L134 Willys engine. We will wander around a bit looking at the various adaptations such as 6 volt , 12 volt and even get into 24 volt systems. Included is a "Step by Step" diagnosis of the ignition system.
Tools - Required and Recommended
Multi-meter (measure coil resistance etc)
Insulated pliers (hold coil wire)
Spark Plug (spare) - (use as spark tester)
Miscellaneous wrenches and screw drivers
6 volt / 12 volt / 24 volt Systems
The only difference in the ignition system from one system voltage to another is the coil. If the coil is not identified on the outside of the coil you can identify it by Low Tension Side or Primary side resistance.
System Voltage Primary Resistance Secondary Resistance
6 volt or 12 volt external resistor 1.5 ohms +/- 8,000 ohms to 11,000 ohms +/-
12 volt internal resistor 3.0 ohms +/- 8,000 ohms to 11,000 ohms +/-
24 volt 6.0 ohms +/- 8,000 ohms to 11,000 ohms +/-
Primary resistance is measured from the (+) terminal to the (-) terminal.
Secondary resistance is measured from the (-) terminal to where the coil wire plugs in.
The ignition system on a L134 Willys called a Kettering Ignition System and is really quite simple. It consists a Battery, Ignition coil, Points, Capacitor (condenser), Distributor Spark Plugs and Spark Plug Wires. When the points CLOSE electrical current flows through the Low Tension Side of the coil. This winds up the coil like a spring. When the points are OPENED the energy stored in the coil is induced into the coil windings on the High Tension Side and a very high voltage (10,000 volts) is sent to the distributor. The distributor sends it through the Spark Plug wires to the Spark plug and a spark occurs at the spark plug.
Drawing courtesy of Mustang Sally.
A more complete description of the Kettering Ignition System is available here
http://users.mrbean.net.au/~rover/ketterin.htm
Step by Step Diagnosis (trouble shooting):
Spark voltages are normally 5,000 volts to 15,000 volts and can be 40,000 volts.
Before beginning, make sure the coil wire and spark plug wires are dry and in good condition.
1) Disconnect both sides of the coil (+) and (-)
2) Check primary resistance of the coil from the (+) to the (-). Resistance should fit the following table
a) 1.5 ohms +/- 6 volt or 12 volt external resistor
b) 3.0 ohms +/- 12 volt internal resistor
c) 6.0 ohms +/- 24 volt
3) If the primary resistance checks NOT OK replace coil. If it checks OK continue to step 4
4) Check secondary resistance of the coil from the (-) to the high voltage connection. Resistance should fit the following table
a) 8,000 to 11,000 ohms +/- 6 volt or 12 volt external resistor
b) 8,000 to 11,000 ohms +/- 12 volt internal resistor
c) 8,000 to 11,000 ohms +/- 24 volt
5) If the secondary resistance checks NOT OK replace coil. If it checks OK continue to step 6
6) Connect a jumper form the (+) side of the coil to the (+) side of the battery.
7) Connect a jumper from the (-) side of the coil and leave it hang in air.
8) Disconnect the coil wire from the distributor
9) Holding the coil wire RUBBER INSULATION. Hold the metal end close to the engine (1/8” to 3/8”)
10) Ground the wire from the (-) side of the coil (step #7) and un-ground it.
a) If no spark occurred, recheck for proper application of #6 through #10
i) If still no spark replace the coil wire with a known good coil wire and continue with #10
ii) You MUST have spark in this step before continuing to next step.
If all else fails replace the coil with a known good coil. Coils have been known to pass the resistance check but break down under load
b) When spark occurs then proceed to next step.
11) Connect the normal wire from the vehicle to the (+) coil terminal and turn ignition ON.
12) Check voltage at coil (+) terminal.
a) No battery voltage. Repair vehicle wiring.
b) Normal battery voltage? Continue
13) Perform #7 through #10
a) If no spark occurred, recheck for proper application of #7 through #10
b) When spark occurs then proceed to next step.
14) Connect the (-) side of the coil.
15) Holding the coil wire RUBBER INSULATION. Hold the metal end close to the engine (1/8” to 3/8”)
16) Have assistant run starter motor (Turn key, press button, step on starter, etc)
a) When spark occurs then proceed with #17
b) If no spark occurs then proceed to POINTS NOT FIRING COIL
17) Plug coil wire back in distributor.
18) Remove a spark plug wire from a spark plug.
19) Connect the spark plug wire to a spare spark plug with the gap set to at least 0.035”. (1/8” to ¼” is better)
20) Position the spark plug so the threads are touching the cylinder head and the gap is visible.
21) Have assistant run starter motor (Turn key, press button, step on starter, etc)
a) When spark occurs then proceed with #22
b) If no spark occurs then proceed to NO SPARK TO SPARK PLUGS
22) Repeat #18 through #21 for each spark plug wire
a) When spark occurs at each spark plug then proceed
b) If no spark occurs then proceed to NO SPARK TO SPARK PLUGS
23) Remove spark plugs
24) Clean and gap them to 0.035”
25) You now should have spark at all plugs.
1) Remove distributor cap
2) Insert a piece of paper between the contact points
3) Check voltage at the movable arm of the points
a) No battery voltage. Repair wiring from coil to points
b) Normal battery voltage? Continue
4) Turn ignition switch off
5) Rotate the engine such that the movable arm of the points rests on the top of the distributor lobe
6) Set the point gap to 0.020”
7) Holding the coil wire RUBBER INSULATION. Hold the metal end close to the engine (1/8” to 1/4”)
8) Have assistant run starter motor (Turn key, press button, step on starter, etc)
a) When spark occurs then proceed with #8
b) If no spark occurs
i) File points to remove pitting – repeat #4 - #7
ii) Replace condenser – repeat #4 - #7
9) Replace Rotor and cap continue with Step #17 above
If there is spark from the coil wire to the distributor and not to the spark plugs the problem is
-
Inside the distributor
-
Cap
-
Rotor
-
-
Spark plug wires
Inside the distributor
1) Check distributor cap for cracks and carbon tracks
a) If cracks or carbon tracks – Replace distributor cap
2) Check the rotor for carbon tracks
a) If carbon tracks – Replace rotor
Spark plug wires
Replace with known good spark plug wires
Return to Step #21 above
Oddities - Weird thing I have found:
- Wire terminal crimped to insulation - not the conductor.
- Wire from distributor coil connection to points grounded / or broken.
- Bolt where coil wire connects to the distributor grounded to coil.
- Resistance from distributor body to block is not ZERO.
- Spark voltages are normally 5,000 volts to 15,000 volts and can be 40,000
volts.
Before beginning, make sure the coil wire and spark plug wires are dry and in good condition. - If the points are pitted in a short time, the coil may be the wrong voltage for the application and / or condenser may be defective.
Visitors since December 5, 2007
Copyright Richard N. Meagley Sr.
Last revised:
December 08, 2007.