

| Subject: | Re: testing the ignition coil (85 1.9L) |
| From: | Aerowolf |
| Date: | Thu, 16 Sep 2004 18:17:21 -0500 |
I just re-read this, and I realized... there's a mention of "test coil without a meter". What do you do to test the coil WITH a meter? What meter? Does it have to be analog or digital or something else? -Kyle On Mon, 13 Sep 2004 19:26:51 -0400, Daniel L. Katz <katzd54@yahoo.com> wrote: > kyle: > > a bad coil is truly rare. > > first get an old spark plug and break off the side electrode to make a > tester. then pull off one spark plug wire at the plug and insert tester, > with the center electrode a few mm from a convenient ground (engine or > body). have an assistant crank and look for a spark. if no spark, pull off > coil wire at distributor and again crank and look for a spark a few mm to > ground. if no spark, and assuming coil wire is ok, then go on to the coil. > your test light should have a wire with an allegator clip, which you clip > to any clean unpainted ground (body or engine) to complete the circuit. > with an assistant cranking, test light should turn on more or less steady > when touching coil (+); if not, no voltage at coil (+), which has nothing > to do with the coil. assuming voltage at coil (+), light should flicker > when touching coil (-) while cranking; if no light, coil primary is open > (bad coil); if steady light, other ignition parts at fault. while > cranking, voltage at coil (-) normally spikes to about -300 V, which will > really bite if you close the circuit with your body. if tests at coil +/- > check out ok, then, since no spark, coil secondary probably shorted (bad > coil). > > it is hard on ignition module to make spark jump more than a few mm, or > worse, leave high tension side open, so either re-attach plug and coil > wires or ground them once you've tested for a spark. > > it is possible to have spark voltage on coil wire but no spark at plug > because of moisture inside cap. > > this is pretty brief, but outlines what to do to test coil without a > meter. > > as i said, almost all coil replacements are unnecessary - due to a > mistaken diagnosis, or just plain wrong guessing. > > dan
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