> I am putting an electric fuel pump into an older car & want to use a fuel
> pump relay that will sense when the engine quits and shut off the pump. I
> know that many vehicles had this type of relay.
>
> I'll probably get something out of a wrecking yard - I would prefer to get a
> relay AND socket. Any suggestions as to what vehicles to steal this from?
> Reliability & availability are the two obvious issues that come to mind.

Late 80s early 90s GM or Ford truck
> Again, I'm not looking for a normal relay, but a "fuel pump relay" that
> remains active only as long as it is receiving pulses from the ignition
> tachometer line.

Are you building a relay control circuit that responds to the tach pulses or do you think that a relay can literally be run from the coil negative? The latter isn't going to work. Running thru an oil pressure switch would work much better.