I guess you changed sparkplugs????

You can try another thing, just make the gap of the sparkplugs smaller lets say 0.4 to 0.5mm
you can also change the 2 leads to the coil (123 leads)

I'm very interested in this.... I've heard that the dwelltime (charging time of the coil) is to short with 123, so when your starter engine draines the battery, theres not enough power for a decent spark...

Which coil are you using anyway (only use a black Citroen coil or a yellow Harley coil with 123 even an EVO version)

I'm going to be an expert in 123 these days

Otherwise feel free......

Yup new plugs not tried closing the gap might be a good idea
I made a new supply cable to the 123 and soldered the joint,and remade the earth
New ht leads too
I sit and watch the ammeter as its missing and it's down in the red until the engine picks up,the battery is a new oversize Bosch one as well spins the car over nice and quickly but I think the voltage being low until the regulator kicks in might be causing it as I've read the 123 is not happy at a lower voltage .?

Mattt,
I think you're misunderstanding how the voltage regulator works...
Once the engine's running, the charge rate (amps) is determined by engine speed, with the _voltage_ being controlled by the regulator.
A typical alternator on an A series will put out about 6 amps @ 1,000 rpm ( engine speed) , over 20 amps at 2,500 rpm and so on up to maximum output.

Also, if your car has an alternator, it will have a voltmeter, not an ammeter.
That instrument is heavily damped, so takes some time to reach a steady reading.
It's also 'short scale' so doesn't show much of a reading even with a fully charged battery, which should be 12.7 volts.
If you put a digital voltmeter across the battery terminals, you will find that the voltage rise is faster than shown by the original item.

ken

Am I being thick but I'm sure I read somewhere ages ago that a wider spark plug gap actually helps starting as it promotes a larger spark?

No a smaller gap is easier to overcome, so when power is weak you still have a chance with a small gap a spark is made, with a wider gap you won't get a spark at all....

(you can play with my ignition changing the dwelltime and see what happens), when you make dwelltime smaller (adjusting it over the laptop) this is exactly what happens the engine starts to fail, (mostly first one side or the other) bringing it more down it will starve..


p.s. dwelltime is the loading time of the coil (this is in steps of 0.00001 sec) in my ignition...
and thats why you can set this dwelltime at 12 rpm ranges so at cranking-speed I put it 4 to 5 times higher then at 3000-6000 rpm... because the starter engine is draining the battery, not much is left to load the coil...

Thanks ken for the info I think I meant to type voltmeter lol
I did check the battery when running it was about 12.6 from memory
I've been onto the 123 website and found a thread with the exact symptoms on several cars,all cured by going back to points.
But the reply from the makers was to check for a slightly low supply voltage due to poor wiring
I've checked my ignition switch and all the wires ok,I even ran a spare wire directly from the battery and a separate earth but they made no difference.
Not really sure what to do next as I don't really want to junk it and fit points
They did suggest sending them back to be tested but I can't do that
I guess no one on here has a 123 hey don't use that I could fit to try.?

Idle? What's it read with a few revs on?



Makes sense. A ropy earth and some manky connections can easily introduce a voltage drop. What voltage are you getting between the earth connection and the ignition +ve connection for the 123? If you can get the multimeter's probes onto the actual wire to the 123, rather than the other side of the connectors, that'd be the most useful reading.

I bypassed the 12v supply and ran a cable direct to the battery + terminal.It still chugged away on 1 cylinder so ruled out low voltage.also ran 2 earths again straight to the battery.

I cant remember the idle voltage.rev voltage but i checked and it was fine ( this was about 6 mths ago when i was troubleshooting during the summer )

Worked out which cylnder?

Swop the ht leads around and see if its the same cylnder

James,
swapping HT leads round won't make any difference, as the HT goes through both leads to fire the plugs.
Swapping the plugs might be of interest though, in case one of them is kaput.

Which leads into suggesting a compression check, if one hasn't been done recently...

ken