My girlfriend's car (89 244DL) died on her pretty much without warning. It's temporarily a long distance relationship, so I can't look at it myself. She brought it to what seems like a reputable shop (Autoscandia, outside D.C.), and they said that the voltage regulator was bad. This surprised me, so I'm checking with the wisdom of Brickboard. Here's what happened:

Car was running normally on her commute home from work. She pulls into the parking lot at home, and the speedo needle starts jumping around (she said between 40 & 60 MPH or so). All the while the car is idling, and she said she didn't notice anything too abnormal about how it was idling. She shut the car off, and when she tried to restart it it would crank, but not start.

Other details:
-She said she could hear the fuel pump running
-Over the past few months, I occasionally saw a few dash idiot lights flicker all at once, which I took as an indicator that the diodes in the alternator were on their way out.

So, based on her account, I figured it was likely a bad crank sensor, as those have a tendency to go bad and I don't know if/when hers was last replaced. I was surprised at the shop's diagnosis because I would have expected a faulty regulator to just stop the charging system, eventually leading to a dead battery, but not stopping the car in its tracks. Since she said it would crank normally the battery obviously still has a charge.

I should add that the price the shop charged is reasonable, so I don't suspect anything wrong, this is more for my own learning.

Thanks all!