2005 5.0MPI fuel pump not powering on

Regal_2250

Cadet
Joined
Jul 7, 2022
Messages
24
2005 Regal 2250 Hull
Mercruiser 5.0 MPI 305 hrs

Turn on the key and fuel pump will not power on. Leave key on and fuel pump will randomly start up after 10 or so minutes.
Removed relay checked pins all good. Swapped relays no avail. Jumped power to relay fuel pump is powering on perfectly. Run and kill switch tested and working appropriately. Green wire to relay socket for ground seems to be not getting ground. Put a Jumper wire to a ground on the engine to the green wire and relay is clicking. I don't have the wiring diagram for 2005 only 2004. Does any one have a possible solution to this issue or perhaps a link to an appropriate wiring diagram for this engine. It appears that the 2004 manual is only showing 1 relay and the engine in fact has 2.

Also can anyone tell me how many fuel pumps are on this engine.

Thanks
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
42,619
Most have just one, but could have 2 but will need motor serial number to verify. Probably has a 555 ECM

The FP relay is powered ON by the ECM applying a ground to one side of the relay. The other side is powered on by the Main Power Relay (MPR).
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,348
2005 Regal 2250 Hull
Mercruiser 5.0 MPI 305 hrs

Turn on the key and fuel pump will not power on. Leave key on and fuel pump will randomly start up after 10 or so minutes.
Removed relay checked pins all good. Swapped relays no avail. Jumped power to relay fuel pump is powering on perfectly. Run and kill switch tested and working appropriately. Green wire to relay socket for ground seems to be not getting ground. Put a Jumper wire to a ground on the engine to the green wire and relay is clicking. I don't have the wiring diagram for 2005 only 2004. Does any one have a possible solution to this issue or perhaps a link to an appropriate wiring diagram for this engine. It appears that the 2004 manual is only showing 1 relay and the engine in fact has 2.

Also can anyone tell me how many fuel pumps are on this engine.

Thanks
Have you tried testing the kill switch circuit exactly at the time the fuel pump doesn’t function when key turned ?
 

Regal_2250

Cadet
Joined
Jul 7, 2022
Messages
24
Most have just one, but could have 2 but will need motor serial number to verify. Probably has a 555 ECM

The FP relay is powered ON by the ECM applying a ground to one side of the relay. The other side is powered on by the Main Power Relay (MPR).
I will have to check on the serial number, I'm on shift for the next number of days. Thank you for your reply I will get back as soon as I can
 
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