ignition system voltage question

[Lazy JW]

I would get the engine running with the points first and then convert to the Duraspark later. You said that you have already replaced the points. Are they set at the correct gap? The points simply act as a switch to connect and disconnect the coil to ground. Did you check for continuity through the points to ground? When you know that there is continuity through the points to ground, do the test again with the spark plug in the coil wire to ground. If this test shows good, then try it again with everything hooked up.
But first, you need to get the starter working. The starter may not be bad, the clicking that you describe is often a result of poor connections, or a discharged battery. Clean the battery connections by removing the cables and scraping them clean. One of those battery post cleaners that is made for the purpose works best, they only cost a few bucks, but a pocket knife will get you by, or a wire brush. This means BOTH ends of the cable, including the end that grounds to the block and the terminals at the solenoid. Also the one on the battery. Measure the voltage at the battery, it should read about 12.5 volts. If it is less than 12 volts, it won't do much, so get it charged up. If that still gives no results, then jump the starter straight to the battery. The solenoid is really just a switch to remotely turn on the starter, so you can remove the cable from the starter side of the solenoid and touch it to the battery side. If the starter doesn't run then, the starter is probably bad (assuming that all of the connections are good). If the starter does run by jumping it, then the solenoid is probably bad. This should keep you busy for a while, let us know how it works.
Joe

 

[Lazy JW]

If the coil has enough continuity (low enough resistance) to give a spark at the negative terminal when you jump it to ground, I *THINK* that may mean his coil is bad.

quote]


These coils typically draw somewhere between 2-4 amps at 12 volts. There will definitely be a visible spark at that level of current when you break the connection. In the early days of the gasoline engine before the high tension ignition system was developed, there was a system known as the "make and break" ignition. This used a set of breaker points INSIDE the combustion chamber that used low voltage and the spark that occured when the points opened was used to ignite the air/fuel mixture. As you may imagine, it wasn't very reliable.
Joe

 

[Anonymous]

Ok, I know I am screwing this up checking for continuity. The lowest setting for ohms on the multimeter is 200. I touch the positive lead of the multimeter to the wire from the negative terminal of the coil where it is connected to the points and touch the ground lead to the engine block with the iginition off. The multimeter reads 1, which (according to the meter's instructions) means it is out of range. I increase the setting but it still reads one. I then touch the positive lead to the the ground wire of the points and it indicates 8.5 on the 200 ohm setting. These are both done with the points closed (the points contacts are touching). Thanks for the help.

Mike

 

[Lazy JW]

Since I don't know what your skill level is, please do not take offense but I must ask if you are using the meter correctly? Always check the meter for the "zero" adjustment before testing anything. This is done by touching the two meter leads together, the meter should read zero resistance. If not there should be an adjustment on the meter to accomplish this. Repeat this test any time that you change to a different range. When you can get a reliable "zero" adjustment on your meter, then you can continue with the continuity testing. It should read near zero from the negative terminal of the coil, through the points and on to ground. Hang in there, you'll get this thing figured out yet.
Joe

 

[61Futura]

See if you get the 8.5, or anything other than the 1 out of range reading, when you read from ground to the condenser wire. If you still get a 1, the points are bad or not closed or the condenser isn't wired to the points properly. With good closed points, the meter should read the same as when you touch the 2 meter leads together, ideally zero. If you have a low reading at the condenser and not at the negative coil terminal, the wire from the coil negative isn't attached to the points & condenser, or the wire is open (bad). Have you got the points wired properly? The wire from the coil and the wire from the condenser go to the nuts on the points, and the ground wire goes from the points mounting screw to the distributor body (it's a short wire or braided wire).

And Joe wins the prize for most accurate electronic knowledge in the above posts.

Steve

 

[Anonymous]

maramse;

The ohms reading (ignition off) or volts reading (ignition on) at the points (where the wire is connected) should be nearly identical to the reading at the (-) terminal of the coil, because that wire is only about 12" long.

If the ignition is off, and the points are closed, the ohms reading from the (-) terminal of the coil should be almost 0.0 ohms when the meter is connected to the engine block (black) and the points or coil (-) terminal (red). If you have more than 2.0 ohms at the points, there is a problem with the points themselves, or with the gap in the points. If you have different readings at the points and the (-) terminal of the coil, then you have a bad wire between them. That wire goes straight from the (-) coil terminal to the points, and it is not a resistance wire, just normal wire. This wire can corrode and cause this kind of problem. It can also be loosely connected.

You can check the system for points operation like this:
1. Connect the coil's spark wire (from the center of the distributor) to an old sparkplug and lay the plug on the block, so it's grounded.
2. Turn on the ignition and, with the distributor open, try opening and closing the points with a small, plastic-handled screwdriver. Each time you short the points to ground, it charges the coil. Each time you open the circuit, it should spark.

That's all there is to it!


The advanced part of this class is:
Some Fords have 2 circuits feeding the (+) side of the coil: one comes from the ignition key, thru a resistance wire, to the (+) terminal. The other usually comes from the starter solenoid to that same (+) terminal, but the splice might be buried somewhere inside the wrapped-up wiring harness. It works like this: when starting, it supplies a full 12 volts to the coil to help start. When the starter is released, the voltage drops down to about 8 volts or so for normal running, so the coil doesn't overheat.

 

[80broncoman]

Is your engine grounded to the chassis good? Yes I heard that is cranks,
but that doesent mean it has a proper ground for running.

 

[Anonymous]

Actually it isn't cranking right now. The solenoid justs rapid clicks using a remote starter. It is a new solenoid, but to be sure, I replaced it and got the same result. I replaced the starter, even though the starter was engaging when tested at the parts store, but it was sounding bad. I tried to crank again, no go. I changed the cable from the solenoid to the starter. Still nothing. I've charged the battery and checked the volts (12.01). I've bypassed the solenoid and touched the starter cable to the positive post to the battery. All that happens is the voltage regulator clicks. How and where does the engine ground to the chassis and what other possiblities can I check? Thanks.


Mike

 

[Lazy JW]

If your ground cable from the battery to the engine block is good, then your starter is bad. Pull the starter and get it tested, but it doesn't sound good to me. Bypassing the solenoid like you did is a pretty good test, the only things left are the cables and ground. Where does your ground cable attach?
Joe

 

[Anonymous]

You might also check to see what your voltage is doing while cranking. I forget the limit, but if it drops below 8 or 10 volts, you may not have enough cranking power in the battery. You might also take off dissassemble and clean the starter up if it is old. The plunger inside can get sticky.