How to test coilpacks?

[sluis05]

Hey everyone, I am wondering what the best way to test my coilpacks will be? They only misfire after the motor is warm and above 5 rpm.. I've been going though them one by one on the side of the road but I'm getting no where. Any quicker ways?

[leeaspin]

Check your plugs re gap them or get new ones

[gtrjon]

just unplug them one at a time and listen for a change in the sound of the motor. if the motor starts misisng or running on one less cylinder you can assume the coilpack that you unplugged is still good.

[drew6]

Some times I wonder why people even bother replying..

The proper way to do it is to use a multimeter and measure the resistance between the + and - terminals on the coil. It should be between 0.6 and 0.9. Mine are currently around 1.2-1.4 and while using the stock gap (1.1mm) it was misfiring to point where the car wasn't even driveable. I dropped the gap to just under .8mm and now the misfiring is gone untill around 8500rpm. If you find the coils are on the way out try dropping the gap on the plug as a "band aid" fix untill your new coils come in.

Best of luck.

[evilgtr]

drew6 do those numbers apply for after market coils to ? what would you say the limit is to maybe replace them ? anything over 0.9 ?

[M13]

Also, a lot of ppl may have 'decent' coils, but have crispy, decrepit and shorted coil wire looms.

Coils can't do much good if their wires are shorting out all the time.


OEM loom can be sourced via sponsors and guaranteed to last 15 years, hell it did in your car before it crapped out right?

[caliber676]

Some times I wonder why people even bother replying..

The proper way to do it is to use a multimeter and measure the resistance between the + and - terminals on the coil. It should be between 0.6 and 0.9. Mine are currently around 1.2-1.4 and while using the stock gap (1.1mm) it was misfiring to point where the car wasn't even driveable. I dropped the gap to just under .8mm and now the misfiring is gone untill around 8500rpm. If you find the coils are on the way out try dropping the gap on the plug as a "band aid" fix untill your new coils come in.

Best of luck.

You named one test, what happens if the secondary field windings are faulty? That test is only testing the primary windings. This is not the only test that can be done to check, nor should it be your only test. Realistically you should use a labscope and coilpack adaptor to view its pattern, but not everyone has a labscope. A good test is to run a length of vacuum or fuel hose between the pack and plug that with fit snug over the coilpack end (with rubber boot removed) and the spark plug. Then connect a test light to battery ground and touch the end of it to the rubber line and you can observe the sparks with the light. idle should drop slightly, sounds strange but it works. Its a more preferred method to unplugging.
A resistance test is a good test to be done, but if your relying solely on that, you may overlook components that test fine for resistance but have another problem. This is especially true when working with ignition components or any voltage inducing component that contains more than one set of wires.