Hi i had now 2 times an explosion in the exhaust lately when putting the car on contact. So not starting but just by putting it on contact. A loud bang and a big black smoke or soot cloud coming of the tailpipe. For the rest nothing strange starts always good. I have a 123 ignition. Any ideas?

Could it be because you haven't been going directly to 'start' mode?
Once a 123 has been powered up, it will switch off the feed to the coil within several seconds if it does not detect any rotation of the camshaft.
That 'shutdown' will result in an HT spark being produced and if there's a combustible mixture in a cylinder, it will make a bit of a bang...

If this is true then 123 is even worse as I already thought.. Why for god sake would you feed the coil when you turn on the ignition... A simple piece of code could avoid this.. Charge the coil only from the 2. pulse of the trigger... (as I do).. Thats the 1-2 in my ignition...

But you are probably right again Ken.... roll: roll:

Why do'nt you have Geo's ignition in your car ?
Supplier lives around the corner !

there wasn't an "geo ignition" at that time i put it in...
And the bang came instandly as i turned the key... and the explosive mixture must then have been in the engine overnight.

6 Corners to be exactly Geert... (when the roadworks are finnaly finished in our town)

No problem for a good engine to keep an explosive mixture overnight..

So Ken is right about that the coil gets charged (probably when the pickup is right above the sensor) when you turn on the the ignition. There will be a safety mechanism in 123 that after some time (half a second or so) the coil is stopped from charging when your engine doesn.t turn (as in my ignition) and that ignits your mixture then..

and it can so easely be fixed... oh dear oh dear...

well it'has a great Laurel & Hardy effect on people passing by...

Could be a useful starter ??
https://en.wikipedia.org/wiki/Coffman_engine_starter
BobH

Hey, Geo's back!