No start.

[Ray White]

Hi John. Please forgive my ignorance but I am not good at electrics. I also tend to get confused easily these days. I will need guidance.

[Chris KC]

I've never used a voltmeter to get an A7 started.
Just work systematically through the ignition components, one by one, and check they are in place and correctly connected and any contacts are clean. 
If that gets you nowhere, replace components one by one with other (hopefully new or sound) parts. If you still have your old coil which was working, put it back again.
Think about what you have changed since the car last ran, and look at that first.
My top picks are
(1) dirty or mal-adjusted points
(2) broken LT lead
(3) poor connections, anywhere
(4) carbon brush in distributor cap fallen out
(5) sheared distributor drive pin
I never take the car anywhere without a selection of ignition parts, usually in multiples, stashed in the boot. If I have space I carry a fully assembled distributor or at least the base plate ready to swap.
Best of luck...

[Ray White]

I have always used a multi meter. It is just another tool in the box. Like most things, however, if you haven't needed to use one in years, you forget what to do with it. ...or at least I do.

[Duncan Grimmond]

FWIW ...
I start with the plugs out , ignition on, press or pull starter... sparks at plugs?
If not, distributor cap off, turn engine, are points opening? Is there a gap?
If not, ascertain why : adjust points, check carbon brush is still in the cap.
Remove coil and replace with a known or new item and try again. Did I get the wires onto the correct coil terminals?
If it fails at this point I usually swear a lot and fit a hot wire directly to the coil to avoid any breaks in the switch/starter circuit.
If it still will not spark I swear again and call a friend to help identify my stupid error as my experience tells me that most faults in the electrical department are usually traceable to operator malfunction...

[Ray White]

Everyone says substitute the coil for a known good one.  I did this but it was a new unused spare coil with correct resistance readings but I am still not getting a spark.  Is it possible that this new coil is also faulty despite the readings?  I will probably buy another new coil anyway.


I have tried cleaning the points with fine sand paper.  They look O.K. with no pitting and still plenty of material on them.  I will try running an earth wire from the distributor body to see if it makes any difference.

As to operator malfunction.....tell me about it.

[Duncan Grimmond]

With the dizzy cap off and the ignition on, can you make the points spark by opening them using an insulated screwdriver?

[Ray White]

Yes, I am getting a spark at the points.


Where do you put the ammeter probes to get a reading?

[andrew34ruby]

Yes, I am getting a spark at the points.


Where do you put the ammeter probes to get a reading?

To measure the current (amps) through the ignition system connect the ammeter probes across the ignition points (closed). Then as you open the points you should see the current on the meter.

But........ I have never ever measured that current, why would you?

Using a test lamp can be easy

https://www.amazon.co.uk/Draper-36583-Au...d_source=1

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  test lamp.jpg (Size: 21.39 KB / Downloads: 110)

These are easier to use than a meter. It is just a simple light, but one with a tungsten light (not LED) is like measuring the voltage by how bright it lights.

The AA issued me with one of these over 40 years ago, and at the roadside I diagnosed and fixed thousands of points ignition problems. I always carried a meter of my own as well as the light, but that simple light is very useful.

[Malcolm Parker]

In the almost 50 years that I have had Austin 7's, I've only ever used a test light like the one above.  I  take the distributor cap off and remove the centre HT lead from the coil (leave it in the coil of course).   Ignition on I open the points with my finger nail whilst holding the HT lead from the coil about 1/4" from the cylinder head.  You should get a spark from the HT lead accompanied by a crack.   If the spark is so weak that it won't jump 1/4" I would be concerned.  In my experience if there is no spark at all the problem usually lies in the distributor, normally to do with the base plate.  It is very easy to get a short or bad earthing with the Lucas DK4 (Ruby) type distributor.   I keep an early type manual advance/retard distributor in the car purely to use for fault finding and also as an emergency get me home measure.   I also try to use old coils, condensers and points rather than modern replacements.

[Ray White]

What I am trying to establish is why the coil won't produce high tension.  Apparently I need 4 amps at the points for this to happen.  At the moment , doing what you suggest,  I am getting 3.5 amps across the Lucas points.