1991 740 NA Regina FI.

The car has been hard to start for about 2 weeks. Finally stopped and will not start.

I have replaced the MAP and FPR.

I checked and the fuel pressure is about 40 psi. Plenty of volume. So I suppose we can rule out the fuel pump and fuel pump relay.

I put a spark plug tester in line and seem to be getting a good spark. I cranked it a bit and checked #1 spark plug which was dry.

After searching a bit, I suspect the radio suppression relay or the crankshaft position sensor.

There are two relays cliped to a bracket on the doolant reservoir. Which of these is the RSR? (BTW, I understand that the other is a "cooling fan relay". WHat cooling fan is this? The car has a fan on the water pump.) I switched the relays, still no start. I pulled the left relay (closeest to the engine) and took it apart. It looks fine.

I haven't looked at the CPS.

Are the CPS and the RSR available from car parts stores, or just the dealer?

Thanks,

Steve