First thing there is nothing wrong with there being 12v (or in your case 13v) at both the + and - terminals of the ignition coil. The coil has a primary side and a secondary side. Both are just coils of wire. The primary side of the stock coil should also have a 3 to 4ohm ballast resistor.
Should there be 12 volts on both sides of the coil?
Yes, if the points are open and/or the electronic module is NOT CLOSED then you will measure battery voltage on both the coil (+) and coil(-) terminals. Since there is no current flowing through the coil (no path to earth) then both sides of the coil will be at the same potential.
How can you tell if a 12 volt coil is bad?
Is there a positive and negative on a coil?
When you hold the coil so the plug wires are to the left (like standard shovel or evo mounting, mounting holes at the rear), the negative side is on the top and the positive is on the bottom.
Related Question Should a 12 volt coil have power on both sides?
How do you test a 12 volt coil?
To check your coil, ensure you have 12V going to the positive terminal. Once you confirm that is the case pull the wire out of the centre of the distributor and hold it a cm away from the distributor centre terminal. Have someone crank over the engine, and there should be a nice blue spark..
How do you know which ignition coil is bad?
Which side of coil goes to points?
This part breaks the current that's going to the coil. The coil's ground side connects to breaker points, which are connected by a lever to a cam in the middle of the distributor. When the lever is pushed by the cam, the coil loses its ground and creates its high-voltage pulse.
How do you check the power of a coil?
Locate the positive or power wire attached to the engine coil. Check for power using a test light. If this wire has no power, then your ignition coil is not receiving current. You should check the wiring from your ignition switch to the coil for breaks in the wire and repair them.
How many volts does a 12 volt coil have?
The coil becomes a transformer, stepping the voltage up. If your car uses a 12 volt battery, the 12 volts you put into the primary side of the coil will exit the secondary side as 30,000 volts!
How do I test my ignition coil power supply?
Should ignition coil have power on both sides?
The power from the ignition switch need to go to the plus side of the coil and the negative goes the the distributor on a 12v system. That should be opposite what it was on a 6v positive ground.
How do you check an ignition coil with a multimeter?
Insert one of the multimeter's probes into the center opening of the coil, contacting the metal terminal inside the coil. Touch the second probe of the meter to the ignition coil's grounding terminal. The meter should read 6,000 to 15,000 ohms. If it does not, the coil's secondary winding is faulty.
How do you check if a coil is good?
The only safe way to test for spark is to use a spark plug tester tool. If a coil problem is suspected, measure the coil's primary and secondary resistance with an ohmmeter. If either is out of specifications, the coil needs to be replaced. A coil can be easily bench tested with a digital 10 megaohm impedance ohmmeter.
Can bad ignition coil cause rough idle?
As the ignition coils are among the ignition system's most vital components, an issue can cause spark to be compromised, which can quickly lead to performance issues. Faulty coils may cause the vehicle to experience misfires, a rough idle, a loss in power and acceleration, and a reduction in gas mileage.
Does my ignition coil need to be grounded?
The simple answer is no, the coil case does not have to be grounded for the ignition to work properly.
Why do I have power to my coil but no spark?
There are a few reasons for no spark, new coil pack could be defective, crank sensor, ignition module or bad wire in primary circuit, faulty ECM/PCM. You may have to have a good technician have a look, diagnose and estimate repair. Second link gives detailed instructions for testing and diagnosing coil pack.