Date: Tue, 14 Sep 2004 19:11:23 -0400
Reply-To: "Daniel L. Katz" <katzd54@YAHOO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "Daniel L. Katz" <katzd54@YAHOO.COM>
Subject: Re: testing the ignition coil (85 1.9L)
On Tue, 14 Sep 2004 13:19:17 -0500, Aerowolf <aerowolf@GMAIL.COM> wrote:
>Thanks for the help!
>
>Would it work to just ground the old plug's side electrode, instead of
>knocking the electrode off entirely? YES That way, the gap could be kept
>at the 0.028" to 0.031" that the book recommends? Or should the gap
>be a bit wider than the normal plugs to test for actual coil voltage?
>
>(I went a bit overboard and bought a battery ground cable to ground
>the engine to the body under the ignition relay panel -- the old strap
>that had been there wasn't there, and I wanted to ensure I had a good
>ground. so I'm pretty sure that grounding isn't an issue here.)
>
>In the event that the + and - both show a steady voltage, which other
>parts might I have to worry about? How difficult is it to replace a
>Hall Effect Generator inside the distributor, if it comes to it? (or
>should I just give up and buy a new distributor, since that's a lot
>easier to install than rebuilding an old one?) How could I verify
>that it's that, and not the ignition control unit? WORRY ABOUT THIS IF
AND WHEN THE TIME COMES.
>
>Also, here's a part of my lack of training showing through: On the
>crankshaft, if the timing mark is at TDC, does that mean that the #1
>cylinder is at TDC? YES, BUT NOT NECESSARILY 0 DEG - CHECK THAT ROTOR IS
POINTED AT #1 TERMINAL ON DISTRIBUTOR. Or does it have a multiplier such
that it could
>be one of 2 or 4 cylinders at TDC? In the latter case, how would I
>tell when it's on #1? (please forgive my ignorance here -- I'm asking
>because if I have to replace the distributor, I need it to be at TDC
>cylinder 1.)
>
>-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
>>
>>
>>
>> On Mon, 13 Sep 2004 09:40:54 -0500, Aerowolf <aerowolf@GMAIL.COM> wrote:
>>
>> >Heya, in my continued travails of getting Morgan running again (it
>> >lost spark on the highway), I have found that people seem to suggest
>> >that there's only a few pieces that can fail, with the coil being the
>> >most likely. One of my friends has suggested that putting a test
>> >light on the coil contacts would be a good idea, to make sure that the
>> >ignition control unit is doing its proper job. (his suggestion is
>> >that if the light flashes while I'm cranking it, the ICU's doing its
>> >job, and the coil isn't.)
>> >
>> >My question is, "where would I put the test light contacts?" There
>> >are three contacts on the coil, one of which is the
>> >high-voltage-to-the-distributor, one is two-green-wires (marked "-1"),
>> >and the other is three individual black and black/white wires (marked
>> >"15+").
>> >
>> >Assuming I'm reading this right, the 15 terminal would be where I push
>> >the probe, and I would connect the clip to ground? I don't want to
>> >damage my ignition system, and since I'm not the best electrician on
>> >the planet, I'd like to make sure that my assumptions are correct.
>> >
>> >Any suggestions? Thanks!
>> >
>> >-Kyle
>>
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