[s-cars] coil diagnosing

[Adam Cramer]

I am also having difficulty testing my coils. From the write-up 
procedure....."Disconnect the coils that aren't being tested" How do you 
disconnect the coils? 
 And ditto on the "short plug wire" question.

 On 7/14/05, pkrasusky at ups.com <pkrasusky at ups.com> wrote: 
> 
> 
> Thanks Chris. Exactly the write up I was looking for, I recall reading
> that awhile back. Will give the autozone tester a try. Yes, my wire
> insulation all looked great, much better than that on many others I've
> seen certainly. Oh well.
> 
> Question: "use a short plug wire"... like any old spark plug wire I
> have laying around?
> 
> -Paul
> 
> 
> -----Original Message-----
> From: chris chambers [mailto:fastscirocco_2000 at yahoo.com]
> Sent: Thursday, July 14, 2005 10:20 AM
> To: Krasusky Paul (WQQ2PXK); s-car-list at audifans.com
> Subject: Re: [s-cars] coil diagnosing
> 
> 
> I will assume you already checked the coil wires for breaks, this is a
> known problem. Others have "fixed" their coils by simply wrapping the
> break in electrical tape.
> 
> I have a bad coil and while searching fouond the following test
> procedure.
> 
> 
> "Here is hopefully a quick and inexpensive test for your suspect coil.
> Go buy an adjustable spark tester. Try to get one with the thumb screw
> that you can manually adjust the gap with. Cost is usually around $9.00
> 
> Lay the coil packs on the valve cover.
> Disconnect the coils that aren't being tested.
> Use a short plug wire and connect one end to the coil to be tested and
> the other end to the spark tester. Adjust the spark tester to, I'll say
> start with the 0.020 gap size. This will probably equate to about 1/4
> inch on the tester. Get someone to crank the engine while observing
> spark. There should be a nice blue, crisp sounding spark. Proceed to
> test all coils to get a baseline as to the spark quality. Then proceed
> to adjust the spark tester to a bigger gap while observing the quality
> of the spark After some time and patience you will notice that the
> spark will turn yellow and will not have that crisp sound as the
> others. Obviously this will be the bad coil. On a side note you may
> also want to disconnect the injectors so as not to load the converter
> up with raw petrol.
> 
> I use this test all the time it never fails. The reason the tester is
> so effective is because you're dynamically testing the coil. As you
> know when the spark plug is in the cylinder ,the spark "has to under
> extreme pressure try and ionize the gap.This puts extreme loads on the
> igniton coil secondary circuit when your are under load/boost. This
> tester will simulate this condition every time. "
> 
> 
> Searching the net I found a pic of an adjustable spark tester here:
> http://www.drivewerks.com/catalog/images/tools2003/THE-404.jpg
> 
> And have since found the tester available at Auto zone.
> 
> 
> 
> HTH
> Chris
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