E30 Zone

Hi. Can anyone suggest a cure? I'm trying to purchase an '89 325is, but it's over 1000miles away. The car transporter guy wants it driveable.
It will start and run for a few seconds and then stops and won't restart or even fire for another hour or two.
The seller said it sounds like a carby car that empties a fuel bowl.
He has tried removing the fuel pump and giving it a tap in-case it was lazy contacts.
It's in a small country town and the local (only) mechanic is "away" until next week.
Any suggestions? Thanks.

I came across an E30 with similar symptoms once, and it was the fuel pump. It would run under full battery voltage, but quit under cranking voltage, and not restart.

And quite correct you are too. New fuel pump - now works! Thanks.