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Fuel pump operation

D

dobber13

Member
Joined
Nov 16, 2002
Location
elgin s.c. 29045
Why didn't Volvo make the fuel pumps come on when key is in the start position instead of the on position? I would think that priming the fuel system before starting would make for quicker starts. Can this be changed on a 85 B21ft?
 
1 don't mess with things that work
2 think twice when you are confident you are going to outdo the Volvo engineers
3 better is the enemy of good
4 how do you get the key to start without going through "on"?
 
It's a safety thing - you don't want the fuel pump running when the engine is stopped. For instance, after an accident you don't want to pump extra fuel onto any fire, or puddle on the ground.

K-Jet uses the distributor (actually the coil) to detect cranking/running. This energizes the fuel pump relay as long as the cranking/running continues.
 
dobber13 said:
Why didn't Volvo make the fuel pumps come on when key is in the start position instead of the on position? I would think that priming the fuel system before starting would make for quicker starts. Can this be changed on a 85 B21ft?
Click to expand...

What position is "start"?
 
After installing a Deplhi main pump, I now notice a distinct "whine" of the pump (as it pressurizes the system I ass-u-me)anytime time the key is turned to ignition position(Christmas lights on dash).

1992 240
 
Otto Mattik said:
After installing a Deplhi main pump, I now notice a distinct "whine" of the pump (as it pressurizes the system I ass-u-me)anytime time the key is turned to ignition position(Christmas lights on dash).

1992 240
Click to expand...

Ahhh the whiny Delphi pump. I have one. You'll know when it stops working.
 
Thanks for all your replies,I don't plain on changing it I just was interested in knowing why Volvo ran it that why.You got to love Volvo safety.
 
bobxyz said:
It's a safety thing - you don't want the fuel pump running when the engine is stopped. For instance, after an accident you don't want to pump extra fuel onto any fire, or puddle on the ground.

K-Jet uses the distributor (actually the coil) to detect cranking/running. This energizes the fuel pump relay as long as the cranking/running continues.
Click to expand...

Which is why the cars have a rollover sensor.
 
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