Question87 Alfa Graduate Fuel Pump
No voltage is getting to the main fuel pump. When 12v jumped to pump car runs. I am an engineer but the shop manual is totally confusing
and not comparable to a basic EE schematic diagram. The resistance of both main fuel pump wires when disconnected from the pump is zero to each other and zero to ground. I am left with the following choices. Either get a meaningful schematic and try to troubleshoot. From a previous post http://experts.about.com/q/804/546689.htm the wiring sounds bizarre;or get a generic 12v relay
wire the primary to ignition switch and switch the higher current from the battery to the pump
with an in line fuse. Would appreciate your help. There are at least two relays behind seat.
The large relay is clicking and replacement did not work.
AnswerThe fuel pump relay must receive a signal from the coil to operate. All grounds need to be cleaned. The ECU ground terminals are 5,16,17. The ground for the fuel pump relay is through terminal 28 on the ECU. This circuit is shared with the other relay which provides positive for the injectors.
Make sure all relays have surge protection between terminals
86 (+) and 85 (-). This does not apply to the fuel pump relay as it is proprietary and always has that protection.
The clicking is probably because the connection from the coil needs to be cleaned up. However, clean all ground connections as they always corrode.
(The fuel pump relay has one more connection than the injector relay).
