Hello Björn,

I think the fuel pressure regulator needs to be replaced. Here is a link to my friend's webpage with the instructions on how to change it out:
http://www.geocities.com/cobramsri/Regulator.html

Make sure to unplug the fuse for the fuel pump and then try to start the car; this will remove the fuel pressure and keep the gasoline out of your eyes when you remove the part. Don't ask me why I know this

I hope this helps.

Regards,

- Jeremy

1990 V8Q Zyclam Portland, Oregon (USA) http://www.MyV8Q.com/ Fun, Fun, Fun auf der Autobahn