There is much written on the Forum about this issue but I have a new clue, at least for my situation.
The vehicle is the one year only '91 940 SE and starting about 6 mths ago the illusive non-start or random stalling scenario began occurring. It has always restarted, sometimes immediately, sometime after much cranking. I'm familiar with the possibilities of; crank position sensor, fuel pump relay (both the one inside by the fuse panel & the larger one under the hood), and the ignition module on the LF fender by the battery. I'm sure it is electrical because it occured in the driveway one time and I immediatly connected my timing light which showed no spark for several engine revolutions, then showed spark & the car started immediately.

Question is, which component would most likely be failing thus intermittently interrupting the primary voltage to the coil. I suspect that's what happening? Any wise heads out there? There are few things more worrisome than knowing your wife might be suddenly stranded anyplace!! TD

 

Have you inspected the distributor for any damage or signs of excessive wear?

 

I would check the crank position sensor. It's located on the top of the bell housing where the engine & transmission meet. It has a fat coax cable that runs to a connector on the firewall. Inspect it. If the insulation is cracked and flaking it definitely needs replacement. More than likely it is the source of your stalling.

 

I would also check here first, and CPS is a relatively cheap fix

 

My car did exactly that and it was the CPS, even though the cable looked ok from the outside. Once I had it out I opened it up and the wiring was crumbling in some spots.

 

Well I did both things since they were both in the same area, replaced crank-position-sensor, and cap rotor, plugs, points, & condenser, wait a minute, no points or condensers since my 122s & 140s!! I realized that it's been 7 yrs since I replaced the plugs thus they were a real bugger to get out! So far the car is performing great but how can I be sure that was the problem? Stripped the CPS wire down & no evidence of cracking. Is there a resistance spec for the CPS so I can know if it's bad? TD