How to test a coil ?

Jan 31, 2009 11 Replies

Hi all



I have this Kia Pride car and no HT current coming out of the coil, hence the car is not starting. There are two wires coming into the coil, one shows 12v current the other one is zero.



I do not know whether it is the coil or electronic contact breaker in the distributor which is not working.



My question is how to test these two in isolation before buying either or both units ?



Thanks for your thoughts.


The Kia Pride is not serviceable, and should be replaced if it fails.

Three, actually: the coil, the sensor in the distributor, and the amplifier/control unit.

Well, to test a coil, you can use a 4 ohm reistor and a switch. Connect a spark plug to the coil HV terminal, grounding the body of the spark plug, Ground one of the low-voltage terminals, and connect the other terminal through the 4 ohm resistor to the battery (+) for a second, then disconnect. On disconnect, the plug should spark.

And, of course, all the wiring that interconnects these items can benefit from connector-jiggling and inspection for rodent toothmarks.

A dwell function found on some DVMs will show if the coil is getting the correct signal from the sensor. Connect between coil negative and ground.

*Why is it that most nudists are people you don\'t want to see naked?* Dave Plowman dave@davenoise.co.uk London SW To e-mail, change noise into sound.

On 2/1/2009 3:39 AM Dave Plowman (News) spake thus:

But that requires that the car is running, doesn't it?

Made From Pears: Pretty good chance that the product is at least mostly pears. Made With Pears: Pretty good chance that pears will be detectable in the product. Contains Pears: One pear seed per multiple tons of product. (with apologies to Dorothy L. Sayers)

No - it should read when cranking. Although an allowance will need to be made from a running reading. Assuming you can find out what the dwell should be. Somewhere around 30 degrees is a good starting point.

*Some people are only alive because it is illegal to kill. Dave Plowman dave@davenoise.co.uk London SW To e-mail, change noise into sound.

On 2/1/2009 4:14 PM Dave Plowman (News) spake thus:

Ah, so.

Personally, I like Vista, but I probably won\'t use it. I like it because it generates considerable business for me in consulting and upgrades. As long as there is hardware and software out there that doesn\'t work, I stay in business. Incidentally, my company motto is "If this stuff worked, you wouldn\'t need me". - lifted from sci.electronics.repair

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Maybe so, but maybe not. There are lots of electronic ignition modules that hit the coil with 300V at the instant a spark is wanted, and leave the coil unpowered otherwise. I have no idea what this Kia model uses...

Indeed. If the coil were grounded with the ignition on but the engine not running it could overheat and possibly fail - as well as drawing current not needed. This could happen with points ignition - hence warnings about not doing this. Most electronic systems prevent this happening.

*See no evil, Hear no evil, Date no evil. Dave Plowman dave@davenoise.co.uk London SW To e-mail, change noise into sound.

Haha. So thats why the hood comes welded shut.

"Michael Kennedy" wrote in news: snipped-for-privacy@giganews.com:

check the Ground side of the coil's primary to see if it actually is getting switched to ground. If the "igniter"(Honda term) is not working,the coil never gets switched to ground,so no current charges the coil,and no HT output;you would get a steady 12V reading at the GND side coil terminal.

If there's a Kia newsgroup,perhaps try "alt.autos.kia" or "rec.autos.kia",they would be a good place to ask questions and get some useful specific help for your problem.

You'll want to include info like model,year,mileage in your query. Some problems occur after "X" miles/years on a car,or under hot outside temps,or cold temps,so mention any unusual conditions or odd behavior of your vehicle.

you guys were really helpful. (not!)

Jim Yanik jyanik at kua.net

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