fuel pump question.

[Isabo]

Beloved offspring's boyfriend ran her Boxter low on fuel, filled up and then the car stopped ten yards later. He had it towed and it's in the shop now. I'm guessing some kind of vapour lock. The shop hasn't had a chance to check it out yet. I phoned the previous owner who said the same thing had happened and they had to replace the pump. They were advised to not let the tank go below half! I think that sounds like rubbish on any car, never mind a Porsche. Any thoughts?

[Wayne 962]

Well, yes and no. You should be able to run the pump down to an empty tank and it won't harm anything - if the tank doesn't have a lot of crap in it. What happens in reality is that contaminants that would not normally be picked up by the pump start to get sucked in when the tank gets really low. So, when you run the car low on fuel, then the stuff tends to get sucked into the pump, which can cause it to fail. This happened to me in Vegas with a BMW 3-Series - we had to change the fuel pump out in the parking lot of the hotel with a full tank of gas!

Boxster fuel pump replacement article here: Pelican Technical Article: Fuel Pump Replacement - 986 Boxster (1997-04) - 987 Boxster (2005-08)

-Wayne

[Isabo]

Thanks Wayne,
and especially for the link to the article. I've no intention of doing the job myself (this time) but I love following through on what's being done on our cars so I can understand. The Boxster book is going on my shopping list today. I understand about rubbish in the bottom of fuel tanks, I just couldn't believe the advice the po was given about not letting the tank go below half.
The housewife in me asks if its sensible to hoover out the tank while the pump is out or if it's a matter of tolerating it and eventually replacing the tank?

[Wayne 962]

Originally Posted by Isabo

Thanks Wayne,
and especially for the link to the article. I've no intention of doing the job myself (this time) but I love following through on what's being done on our cars so I can understand. The Boxster book is going on my shopping list today. I understand about rubbish in the bottom of fuel tanks, I just couldn't believe the advice the po was given about not letting the tank go below half.
The housewife in me asks if its sensible to hoover out the tank while the pump is out or if it's a matter of tolerating it and eventually replacing the tank?

When I replaced the pump in my car, I reached in there and cleaned it all out with some windex or some type of mostly-harmless cleaner.

The 1/2 full rule is a good rule of thumb. No one will ever do that, so the 1/2 full rule then becomes the "fill at 1/4 tank" rule. It's good practice not to let the fuel tank run down low. That said, I do it all of the time, even having already paid the price in Vegas (funny, that usually means something else when talking about Vegas).

-Wayne