Trigger Point Conumdrum

Hi,
Thank you - sorry to be so difficult but I really appreciate your help. And not to be even more difficult than I already am but am I correct in that this issue with pin 18 is an external issue and not to do with a problem with the ECU? I guess what I want to know do I look for an issue with the ECU or at an issue with the starter circuit???
Again
I am sorry for being so slow
Peter

Hi Peter,

it is an external signal from starter that the ECU reacts to. Some immediately with start enrichment, some like yours with after start enrichment. But all do start the injectors no matter what trigger points say. That signal is also used for thermo time switch and cold start valve.

I was looking at your site that listed MB part numbers for a throttle switch (1973 slc 450) but I couldn't find mine listed. On the PCB it is 1288 310 023 Is this just the PCB #. And if you were going to replace one would a Bosch 0280120029 fit? I think this is off a 280 sl/c m110. But it states it will fit a 450????
Regards Peter

Hi Peter,

that is just the PCB. The Bosch no is engraved of the back of the T.C.

Hi Just a little update. I got the Throttle switch working and tested the pin 18. At the top relay I am getting over 12 V and at the other relay (directly below) I am getting about 9.5V and this is the same reading I am getting at the ECU.
The spark plugs seem wet.
There seems to be a spark (jumps about 13 mm on Spark plug Tester)
I hear clicking of the injectors when it turns over.
The engine is at TDC (bunny ears poking up) and gap is just over .3 mm (Ive tried slightly both sides).
Ive sprayed fuel and starter fluid into carby and cylinder but still if doesn't fire???
It is a conumdrum

Hi Volker,
I have just had a thought. The diagram of the trigger points that you posted (with the oscilloscope). Are these in chronological order of firing (don't worry about a starting point) and do the colours match the wiring colours.
Eg;
White
Blue
Red
Green

Thanks
Peter