No power to electric fuel pump

F

fisherpeakhippie

Recruit
Joined
Jul 3, 2026
Messages
2
I have a 2005 Yamaha F90 TLRD that is not getting power to the electric pump in the vst tank. I have replaced the pump and it is working but I can't seem to get power to it. The fuses are good and I have power to turn the starter. I can't see any damage to the wiring but I have not dissected them and don't want to. I'm leaning toward the ecu but don't know. Any suggestions would be greatly appreciated. Thanks
 
9

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,283
I believe the pump gets power at key on, but the ecu tells it when to rim by completing the negative side.
so, are you getting 12V + at key on?
 
F

fisherpeakhippie

Recruit
Joined
Jul 3, 2026
Messages
2
No, used a test light on the connector and got nothing when I turned the key on. Used a battery and jump wires to know the pump is working.
 
B

boscoe99

Commander
Joined
Aug 22, 2013
Messages
2,308
The ECU does not provide battery power to the electric fuel pump. Battery power is from the fuel pump relay.
 
J

Jeff J

Chief Petty Officer
Joined
Jun 23, 2021
Messages
576
What tells the pump to pump? It should cycle when the key is turned on and I would assume constantly while the engine is running but I don’t know what controls it. I can’t remember if I can turn it on with the YDS.
 
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