63 Gran Turismo Engine cranks over but no spark?????

[Kullan]

Just had it running for the first time in a couple months. As soon as I flipped on the air switch the car shut off. Tried to start it again and that's when I lost spark. I've been through all the wires and fuses. Could it be the coil and/or the points and condenser?
By the way, it is a V8 Firing order 18436572.

[gordr]

Well, you will have to answer that yourself, by doing some basic troubleshooting. First off, get yourself a test light. One of those ice-pick looking thngs that has a light bulb in the clear plastic handle, and a length of wire on it with an alligator clip on the end. Buy a good one; even the good ones are pretty cheap, and a good one will last for years. No reason you can't make your own, if you are handy.

Clamp the alligator clip to a good ground under the hood, and probe the (+) post of the battery. The lamp should light. What you are doing here is ensuring that your test light works, and that the cable has a good ground. It's very frustrating to try and troubleshoot a circuit with a flaky test light!

Now, turn on the ignition to the "run" position, and check for 12 volts at the (+) terminal on the coil. You may see a little less than 12 volts because of the resistor wire, but the test light should come on with either full brightness or half brightness, depending on whether the points are open or closed. If you see no light at all, then either the resistor wire has gone open, or the ignition switch is faulty. Have a helper trun the engine on the starter while continuing to hold the probe on the coil (+) terminal. If the lamp comes on brightly while cranking, you know that boost function in the solenoid is working. Note that if you were to get power at the coil while cranking, but not with the ignition switch in the "run" position, the car would try to run while cranking, but quit as soon as you released the key. Since you don't describe that happening. I doubt the problem is with power to the coil, unless both the crank and run circuits are faulty.

Now, move the probe to the (-) terminal of the coil. If the lamp showed full brightness on the (+) terminal, it should also show full brightness on the (-) terminal, providing the crankshaft hasn't been turned in the meantime. If it showed partial brightness on the (+) terminal, it should now fail to come on at all when connected to the (-) terminal of the coil. If you see a faint dim glow in the test light, expect to find dirty or maladjusted points.

Keeping the test lamp on the coil (-) terminal, have a helper spin the engine over on the starter. You should see the test light flash on and off repeatedly at regular intervals. If it remains on as the engine turns, then your points are not closing at all, or are so badly oxidized that they won't pass current. If the lamp remains off while the engine cranks, or only flashes very weakly, either your points are not opening at all, or the gap is far too small, or you have a shorted condenser. Condensers usually don't fail by shorting; they go leaky or lose capacitance instead. The points are the most likely culprit here, because it's normal for them to wear out of spec.

Try these simple tests, and tell us what you find. It won't take more than 5 minutes, once you identify the proper terminals on the coil, which are marked that way.

[Gunslinger]

Pull the coil wire from the center tower of the distributor and lay it on the engine block. Crank the car and see if a spark jumps from the coil to the block. If you have a bright spark, then the problem lies within the distrubutor...bad or misadjusted points or bad condenser. If no spark, it could be the coil or back to the ignition switch. You should also check to make sure the distributor hold town is tight and the distributor body hasn't rotated.

Don't have your hand close to the coil wire when cranking the engine or you'll get a shock that will make you glow in the dark.

I'm guessing you have a points/condenser problem. You could also have a cracked distributor cap or have carbon tracking inside it. Regardless, it shouldn't take too long to figure it out.

[Kullan]

Thanks Gord and to the guy down below this post. It's funny, I worked in a garage(auto shop) way back and haven't for many years kept up with stuff. I used your advice and did all the necessary diagnostics...I lost all my tools (long story)...had to go buy a new test light.(it failed and I had to take it back twice)...It was a cheap one....anyway, long story short. I replaced the coil and resistor....it wouldn"t start.....cleaned the points and contact points on in the distributer...it fired right up!!!!! I don't think the coil was bad, but I know the resistor was...the spring was broken.....It wouldn't start until I cleaned the points and cap....GO FIGURE! Anyway, thank you very much for at least getting my head straight and back into what I've learned long ago! I might need you on a future problem, which is Steering and brakes!!!!! Thank you!
Kullan