924Board.org

lostintheeightys · Joined: 08 Jan 2010 Posts: 10 Location: Iowa

Quick question... Does anyone know if the fuel pump relay is to energize the fuel pump once the key is turned to the run position or if the the pump is activated in the start position? For whatever reason mine is set to activate once the key is in the start position and it takes a few seconds to presurize enough to start. Didnt know if I hooked it up to power the pump on immediately if the pump will shut off once there is pressure against it like newer versions of fuel injected autos. Any help would be appreciated.

avaconirl · Joined: 25 Dec 2009 Posts: 48 Location: Ireland

The fuel pump only works when the engine is turning over. It gets a feed from the negative side of the coil in the case of a 2l n/a.This is to ensure that the pump runs when the engine is running and not when the ignition is on but the engine has stopped.
Hope this helps.

lostintheeightys · Joined: 08 Jan 2010 Posts: 10 Location: Iowa

yes, thank you

!tom · Posted: Tue Mar 02, 2010 6:19 am Post subject:

Actually, this behaviour changed during production of the car. You'll have to state if your car is a turbo or not, and what year the car is before questions like these can be answered accurately.
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78 924 NA
5-lug

rkn · Joined: 01 Apr 2007 Posts: 176 Location: Copenhagen

I think it may have to do with the specific pump relay used?
I could swear that my pump has always pressurized when I turned the key to ON, but after replacing the relay last month, it doesn't run until the starter turns.
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1980 924NA ROW

lostintheeightys · Joined: 08 Jan 2010 Posts: 10 Location: Iowa

Thanks all,

My Porsche is a 1979 924 non turbo