Strange Problem 280 SL Starting Running

[blowersix]

Dear guys,
Hopefully one off you can help me with this challenge.

It's a 280 automatic sl with a strange problem.(k-jetronic)
Car has spent 6 years without starting.

New fuel distribution unit installed+filter+cold start valve+relays.
With fuel pump connected car won't start.If you just let the pump work(switch on for 15 seconds )to pressurize the system  then remove one wire from the fuel pump,
car will  start, idle rough and rich for like 3 or 4 minutes.
When  you connect the loose wire back to the fuel pump car will stall imediately.
I suspect a bad wire or ignition switch.Any ideas
Thank for your help ,keep up the great work.
Richard

[Jonny B]

Just to clarify a bit, when you type about k-jetronic. Is this a 107 body (450 SL, 380 SL etc of the 1972-1989) or a 113 (230 SL, 250 SL, 280 SL of 1963 through 1971)? This forum is for the early cars 1963 through 1971. There is a 107 forum for the later cars.

[blowersix]

Thanks Johnny for your reply.
My car is a 280 Sl from 1983.
I will check with the other forum.
Have a good day,Rich