74 Duster (318) ignition not working, not getting spark
This is how the start sequence works.
The schematic shows a points igniton but starting works pretty much the same way.
Before starting no current is flowing out of the battery.
When the key is turned to start current flows through the key switch to the starter relay, through the neutral safety switch and back to the battery negative.
Whenever the distributor points are closed current flows through the coil and back to battery negative.
As soon as the relay closes this would have let the power from the battery go to the starter's solenoid.
Jumping the battery feed A1A to the solenoid post (wire S5) on the relay is used if the relay is not connecting them internally.
Then the starter will connect and draw power.
The starter draws a lot of power.
The first thing you must do is bring the battery up to full charge using a charger. Charge slow is usually best.
The battery voltage will get pulled down during starting. But if it drops to 9 V or below it probably won't cut it.
On a points ignition the ballast resistor does nothing during start. Because battery voltage is already low during start, current is directed around the resistor.
The electronic ignition is a little more complicated during start. The ECU needs power to amplify the signal from the magnetic pickup. The original ECUs needed current regulation. The second ballast resistor served that function when the engine was running (key in run). Later Chrysler ECUs and most replacements don't need the second resistor and only have four wires.
If your car is using the original set up. One resistor should measure 5 Ohms, the other 0.5 Ohms.
I don't think the 5 ohm resistor is used during start. However the power to run the ECU has to go through the .5 ohm resistor. That's how I understand it.
This is how the start sequence works.
The schematic shows a points igniton but starting works pretty much the same way.
Before starting no current is flowing out of the battery.
When the key is turned to start current flows through the key switch to the starter relay, through the neutral safety switch and back to the battery negative.
Whenever the distributor points are closed current flows through the coil and back to battery negative.
As soon as the relay closes this would have let the power from the battery go to the starter's solenoid.
Jumping the battery feed A1A to the solenoid post (wire S5) on the relay is used if the relay is not connecting them internally.
Then the starter will connect and draw power.
The starter draws a lot of power.
The first thing you must do is bring the battery up to full charge using a charger. Charge slow is usually best.
The battery voltage will get pulled down during starting. But if it drops to 9 V or below it probably won't cut it.
On a points ignition the ballast resistor does nothing during start. Because battery voltage is already low during start, current is directed around the resistor.
The electronic ignition is a little more complicated during start. The ECU needs power to amplify the signal from the magnetic pickup. The original ECUs needed current regulation. The second ballast resistor served that function when the engine was running (key in run). Later Chrysler ECUs and most replacements don't need the second resistor and only have four wires.
If your car is using the original set up. One resistor should measure 5 Ohms, the other 0.5 Ohms.
I don't think the 5 ohm resistor is used during start. However the power to run the ECU has to go through the .5 ohm resistor. That's how I understand it.
