do i have to fill gasolin in the fuelpump before i start the engine?

Hi J.

I used to work for a company that manufactured fuel pump parts for Delphi (GM) and Visteon/Ford. I asked their engineers the same question about air (oxygen) in the fuel pump. Some of them had not even thought about it before I asked.

Whatever the explanation, I guess it is not a problem, because you would certainly be hearing about it on the news if cars were exploding whenever a fuel pump were replaced.

I can't imagine being the first engineer to propose to management that "We ought to start building electric fuel pumps with the motor brushes and commutator actually in the fuel". I can't imagine a legal department ever taking that risk - no matter how many tests the engineers did to prove that it was impossible for it to explode.

What year and model of vehicle are you asking about for buying just the pump without the housing? I assume by "housing", you mean the sending unit?

I just read the shop manual for the LH cars (300M, Intrepid, Concorde, LHS) on replacing the fuel pump - it gives no precautions or procedures for ensuring it is filled with fuel before installing and powering up. Also, the parts listings do not indicate a listing for just the pump.

Be careful buying Chinese aftermarket stuff, and off of ebay in general.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

Hah! No. The brushes and brush holders are exactly what I designed and that we manufactured for the fuel pumps. Believe me - they are brush motors. Brushless motors are too expensive for a normal automotive fuel pump.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

They probably build these pumps with brushless motors.

Why don't they make sparks? Or is the motor in a sealed enclosure so it doesn't matter?

Filling the tank with fuel makes it much safer. Fuel vapors displace so much air that it becomes unable to support combustion. I would recommend that you put some fuel in, but it does not have to be totally full to become safe.

No - the brushes "live" in the fuel - are bathed in the fuel as it passes thru the pump.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')