Citroen SM doesnt start

I have tested with other ECU again and also with a Citroen DS ECU, no change....can it be ECU and is there anyone repairing them? (Bosch)
Is the ecu getting pulse from distributor contacts or ignition coil?

Tjena Johan,

well this feature is present in every D-Jetronic ECU. ECU activates fuel pump relay via setting pin 19 to ground in these cases:

1. for 1-2 seconds after ignition is switched ON
2. definitely as long as starter is activated
3. as long as trigger contacts signal a motor rpm of > 250 rpm

So if your ECU does not activate fuel pump relay in cases 1 and 2, it has nothing to do with trigger contacts. Only case 3 is linked to them.

Thanks Volker and Norbert!

I had time now to investigate the system more and with the help of extra hands.
By the knowledge I obtained from you guys and some elbowgrease, we found the problem.
It was Citroen related, a thermofuse that has become weak by time and didnt support the current to the pumprelay.

Im very happy to finaly be one step closer to the summer roads!!

Thank you very much for the help!
Is there some way to contribute to the forum in a modest way?

Regards
Johan Dahl

Hi Johan,

how do you want to contribute? Technical articles are for example very welcome.