I had to stop and think a little about your problem.

You said the amps seemed low and the flow was decent from the RETURN LINE?

If the engine is not running the vacuum would be "0". When the engine runs under a high load the vacuum will be low and the amount of fuel returned to the tank will be low...most going to the engines injectors.

Could the regulator be running wild and not holding pressure? Got ME!

With the injectors off the pressure should be at a higher level. About at least 35 psi. ON THE RAIL, engine running. Stopped it could go up to 65+ psi. and there should be bypass valve in the pump that limits it. Plus no rpm signal, shuts down the pump relay. Thats why you don't hear the pump until you crank. It may run only shorty after you stop cranking and before it can start.

Capacity in liters per minute should be at specifications. The specs. are from the pump directly not through the regulator as I recall. BETTER DOUBLE CHECK HOW IT IS WRITTEN. Quantity will be hard to spec. in, through the regulator, because it varies things. Wish I was mre familiar with the 82 year. I have a '78 CIS and '86 LH.

Pressure is important. It has to be there at all times when it is running to make a good spray.

REST pressure is important. 10 psi to 0 as long as the rail stays full.

Pressure requires more work and more amps. to me. Even at low pressure if flow is high work is being done and amps will correspond to the work done. Its just the basic law, to get something, you work for it.

Leaky regulator or check valves, get you on start ups or in your case, pressure. I think? I missed how your car was acting before it died that day. Usually, there are warning signs. Like hard starts, low power, rough idle..rich or lean drivabilty symptoms. Hope you are looking in the right areas first before we blame electronic fuel injection because I have found that its not always the only problem. The computers adjust things so fast that it can compensate for some ignition and air/vacuum problems easliy.

Hope these suggestions and guessing, are helpful to all, good luck!