Full pump runs continuously

Jim Whiting

Recruit
Joined
Jul 22, 2021
Messages
2
I gave a 1998 volvo penta 5.7 when you turn key on the fuel pump starts pumping as if at full throttle. It does not start pumping. Changed relays but problem continues. Any suggestions
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
43,383
Don't know which 5.7 motor but will assume it has a carb
VP uses 2 diodes (Dumb IMO) which allows power to energize the relay when cranking and ones started, power comes from the alternator to keep it energized. The most likely issue is the ALT diode has shorted.

Put a meter on pin 85 of the relay and see if it has power as soon as key is turned ON

GL fuel pump wiring.jpg
 
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