Hello all, this update on my no/hard starting 940. I have a '91 940, with 190k.
About a year ago it started to give me problems on not starting right away. It got to be more frequent this summer. It would not start but after setting a while it would start. I knew it was not ignition, and narrowed it down to fuel delivery. Changed fuel pump, filter, injectors, relays etc. Still the problem persisted. I finally found it was the radio suppression relay that was defective. This relay and the fan start relay are identical and I even switched them at one point to see if one was bad..both were bad! I found that when I gave the relay good rap, suddenly the engine started. Unfortunlately I discovered this about two hours before the UPS man came with my new relays. This problem has been very frustrating in that it would not show up all the time and was hard to isolate. I pass this along for anyone else who might experience this very hair pulling problem. It always feels good to finally nail the problem and have your car running again like it should.
Good luck to all