[s-cars] spark plugs

James Murray (QB/EMC) james.murray at ericsson.com
Fri Jul 2 12:39:08 EDT 2004

Bad coil... it ruined two plugs on me. I haven't tried this but it's a great way to check your spark (posted by a Candian lister Craig Cook):

A quick and inexpensive test for your suspect coil. Buy a adjustable spark tester. The one with the thumb screw that you can manually adjust the gap with... 

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 something like 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.

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.

Cheers, /JaMu.

-----Original Message-----
From: s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com]On Behalf Of
Elijahallen92 at aol.com
Sent: Friday, July 02, 2004 12:33 PM
To: s-car-list at audifans.com
Subject: [s-cars] spark plugs

Hi, just checking to make sure I have the right plugs. F5DP0R right? I have 
had plugs fail three times in a couple months. What could be causing this?

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