Intermittent fuel pump problem - not electrics?

[Brian28]

Has anybody had a problem with the fuel pump working for 15-20 minutes then cutting out when it still has a power supply? I sold one on ebay (drove the car for over two hours continuous myself and no issues with fuel) , the guy reckons that it only runs for 15-20 minutes then stops. If he substitutes another pump there is no problem, he has done a two hour test with another pump. In my experience the fuel pumps are either working or not working, I've not had one that works for a while then gives up unless there is a power supply problem. Is the pump fault likely (before I give the guy his money back or tell him to go fk himself)?
Cheers
Brian

[daimlerman]

I had an issue similar to this about a year back.

Went to my touring,it started fine in the garage,backed it onto the street,switched off whilst I locked up the garage and it failed to re-start.I few basic checks established that the fuel pump did not run.
So I stripped out the rear seat area to access the pump,put an independent battery on it,and the little bugger ran.Re-connected and the car ran briefly.Thumped the pump,car ran briefly...swapped in my spare,car has been fine ever since....

[Brianmoooore]

I've come to the conclusion that E30 fuel pumps don't like being stored dry. I've had several that were removed from fully working cars, but then gave trouble when installed in a new home.
I always treat them to a few drops of thin oil up the pick up tube when I store them these days, but can't really say if it helps.

[Brian28]

Ok thanks both. Only been off the car for a week or so, works from starting every time no problem but cuts out after 15-20 minutes running. Will give him the benefit of the doubt (and trust it isn't the usual ebay scam merchant sending me back his knackered old pump and keeping the decent one he bought from me!)