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John T
01-16-2003 09:52:35
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Re: schematic in reply to joel, 01-16-2003 06:50:44
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Joel, sorry I dont have a schematic, but can tell you somethign about the coil assuming its a battery powered external coil distributor system. First, when you turn on the ignition switch, a test lamp or a voltmeter should show voltage present at the coil primarys (1 of the 2 small terminals) high (non distributor) side. Then, a test lamp on the low (distributor) side terminal is normally off, since its usually grounded there through the points in the distributor, but should illuminate when the points are open like at high cam ready to fire a piston at TDC on its compression power stroke. With the ignition on and cranking the engine slowly, if the high side isnt always on and the low side flashing on and off, theres a problem like maybe the points (not closing or opening or shorted out or bad) etc and its never gonna spark. With the ignition on, if you remove the distributor cap and use a screwdriver (but dont short it out, a piece of plastic or wood may be better) to open the points (have it on low cam not opening points where they are closed) , the coil should fire a spark. Test that by pulling the coil wire out the top of the dist (leave other end in coil) and placing its metal output end 1/8 inch away from frame, and with ignition on when you open the points, it should fire a spark. Its usually a problem in the points (burned, carboned, pitted, shorted, not adjusted or not closing) or condensor instead of the coil. The points need to be gapped properly and open and close and make good electrical contact wehn closed and the condensor not bad or shorted out for the coil to ever work. You can run a simple continuity check on the coil with an ohmmeter or continuity tester, it needs to have a closed circuit between the 2 little terminal primary leads or else its bad. However, even if it passes simple low voltage continuity tests, it can still be bad and breaking down at high voltage. If you want, e mail me and I can send you a copy of two articles I wrote for Green Magazine which tells more than you ever wanna know about the theory and troubleshooting of coil ignition systems, or check last August and Decembers issues. Good Luck, Ol John T Nordhoff in Indiana
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