Testing 12volt Ford Ignition Coil

I did some testing on my Ford tractor ignition coil put a multimeter on both wire terminal and did not get 3ohms just went to 1 like an open circuit is present does this mean the coil is possibly bad?[/list]

(quoted from post at 22:36:22 09/02/16) I did some testing on my Ford tractor ignition coil put a multimeter on both wire terminal and did not get 3ohms just went to 1 like an open circuit is present does this mean the coil is possibly bad?[/list]

Click to expand...

Ohm is closer to zero than 3 Ohms, so not an open, actually closer to a short or simply a 6v coil.

often low Ohm 6v coils are used in series with a resistor to lower current to a proper level when running on 12v. When you suspect a coil the number one thing to do is, look elsewhere for the problem and the number two thing to do is try a different coil. Save heart burn.

So I'm assuming from what your telling me the coil has short it is a 12volt ignition coil showing just 1ohm instead 3 ohms that would explain lack of spark. Also noticed feeling coolant inside of coil sloshing inside I don't remember them doing this ether maybe my memory is wrong.

So I'm assuming from what your telling me the coil has short it is a 12volt ignition coil showing just 1ohm instead 3 ohms that would explain lack of spark. Also noticed feeling coolant inside of coil sloshing inside I don't remember them doing this ether maybe my memory is wrong.[/quote]ee above post

"on both wire terminal"

So a round can, automotive style coil.
Not the front mount, square, early N style coil. Correct?
If so, probably a 6V coil with a series resistor or simply
a limitation of the meter not being able to actually tell
the difference between 1 and 3 in an inductive coil.

So I'm assuming from what your telling me the coil has short it is a 12volt ignition coil showing just 1ohm instead 3 ohms

Click to expand...

How do you know it is a 12 volt coil? Does it say so on the body of the coil? If so does it also say "external resistor required?

(quoted from post at 05:12:31 09/03/16)

So I'm assuming from what your telling me the coil has short it is a 12volt ignition coil showing just 1ohm instead 3 ohms

Click to expand...

How do you know it is a 12 volt coil? Does it say so on the body of the coil? If so does it also say "external resistor required?

Click to expand...

The coil does say 12 volts and no external resistor required on the side of the coil put there by the manufacture.

(quoted from post at 08:48:13 09/03/16)

(quoted from post at 05:12:31 09/03/16)

So I'm assuming from what your telling me the coil has short it is a 12volt ignition coil showing just 1ohm instead 3 ohms

Click to expand...

How do you know it is a 12 volt coil? Does it say so on the body of the coil? If so does it also say "external resistor required?

Click to expand...

The coil does say 12 volts and no external resistor required on the side of the coil put there by the manufacture.

Click to expand...

hen it is likely bad because it is virtually unheard of to have a measurement error indicating less resistance than is actually present. Measurement errors are to the high side of actual. This is where you have zeroed meter with probes shorted together prior to measurement. It could be a1 Ohm coil for 12v if it was for some high end electronic system, such as MSD or similar, but not for a points system.

(quoted from post at 09:13:16 09/03/16)

(quoted from post at 08:48:13 09/03/16)

(quoted from post at 05:12:31 09/03/16)

So I'm assuming from what your telling me the coil has short it is a 12volt ignition coil showing just 1ohm instead 3 ohms

Click to expand...

How do you know it is a 12 volt coil? Does it say so on the body of the coil? If so does it also say "external resistor required?

Click to expand...

The coil does say 12 volts and no external resistor required on the side of the coil put there by the manufacture.

Click to expand...

hen it is likely bad because it is virtually unheard of to have a measurement error indicating less resistance than is actually present. Measurement errors are to the high side of actual. This is where you have zeroed meter with probes shorted together prior to measurement. It could be a1 Ohm coil for 12v if it was for some high end electronic system, such as MSD or similar, but not for a points system.

Click to expand...

To make sure, disconnect one of the wires from the small post it is connected to (doesn't matter which one as either should isolate the primary) and measure the resistance again.

One easy way to test a coil and it takes not special things like a Volt/ohm meter to do it is have the points closed. Then unhook the ignition side of the coil. Turn the ignition on then touch the wire back to the coil. When you do that you should get a spark at that wire and then pull the wire back off holding the wire going to the distributor cap a 1/4 inch form the block. You should get a good blue/white spark when you do that and it should jump a 1/4 inc gap or more. But if you get no spark it could also be a set of points that are bad. To prove it is the points ground the distributor side of the coil and try the wire on the ignition again. If you have spark then your points are bad or the condenser is bad or the insulator going in the side of the distributor is shorted out