Is there a way to test an ignition coil to see if it's good without having to hook it up in a car?

 

What coil, from what car?

 

I assume you mean checking it on the bench. You use an Ohm meter. I can't remember the exact procedure, but I am sure if you do a search you will be able to find out the specs (resistance) and how to do it. There are high voltage specs, and low voltage specs that have specific peramiters (sp?). If it falls outside of either set of paramiters, it is defective. Hope this helps.

 

I bought a used DelTeq ignition for my 94. There are 12 coils in the box. I only need 4 of them. Each has 2 terminals that go to the spark plugs. Was told 1 or more may be bad.

 

I know on some of the small engines, a coil can test as a good one. But still be defective. Not sure if car ones are the same, but I imagine they could be.

 

Here's the short story:
In the field, with an ohmmeter, you can do some tests that will show the coil is definitely bad.
But, you won't be able to do tests to show the coil is definitely good.


Here's the long story:
That's true of all coils, rather it is in the injectors or your ignition coils.

As an example, if you had a coil that had 2 thousand turns of wire with 2/10th of an ohm per turn, it would measure 400 ohms when good.
And, if one turn got shorted, it would measure 399.8 ohms when it is bad.
The resistance in your connections when you connect the ohmmeter clips could cause it to vary that much. So, it is very doubtful that you could determine a problem.

There is equipment available to test coils, but I doubt you will have it in the field.
So, coil substitution is probably the best bet.

However, if the coil was burnt open, the ohmmeter would show infinite resistance and would be one check that would be valid.
In addition, the coils used in a "waste spark" ignition system, like the Delteq, have secondaries that are floating -- that means they are not normally tied to ground on the secondary side -- so, neither of the secondary (high voltage) towers should show continuity to ground with an ohmmeter -- so, this is another good test for them.
As a side note, the LTCC is NOT a "waste spark" system -- it has one coil per plug.

Tom Piper

 

An ohmeter will only find gross coil failures. An impedance bridge which measures inductance and coil Q can find a defective coil, but the easiest way that anyone can test a spark coil is to pulse the primary with 12v while you have connected a .05 Mfd to 0.1 Mfd capacitor across the primary. If you have a capacitor from an old points type distributor, use that. When you pulse the primary, you will get very high voltage off the secondary wire to ground and you should hold a ground wire within 1/2 inch of the secondary and a good coil will be able to produce a nice snappy spark.

 

http://www.autozone.com/servlet/UiBr...a2.jsp#hd1-1-1

 

Thanks for the input. I will see what I can find out this week-end.