No power to cool fuel pump.
#1
Thread Starter
Registered
Joined: Mar 2007
Posts: 121
Likes: 70
From: SW Florida
Starting a new thread as the other one is 6 years old. 1997 Gen VI 502 mag MPI. It sat for 2 months at the marina and fired up no problem to bring home. On the voyage home, Stbd engine died and I restarted it no problem. Got home and tried to flush it, no power to fuel pump. Things I have tried: swapped fuel pups, fuel relays, ECM's, ignition switches, good voltage, bench tested the fuel pump. In the other thread it mentions a pink wire going to the fuel relay, I unwrapped the wire to the point it makes the bend forward towards the ECU. Im out of ideas. I can hear the relay clicking when I turn the key to ON but no buzz. I can recycle the key and got it to wake up on about the 20th try....then nothing again. Good battery voltage and it cranks fine. Im thinking a short or bad ground. Could it be something stupid like a bad connector to a Tach or Volt gauge? Thanks.
#2
Registered
Joined: Aug 2022
Posts: 91
Likes: 56
Check the cannon plug(main harness plug on motor, usually has hose clamp, or zip tie.)
Had a new tech struggling to diagnose no power to fuel pump.
Told him to wiggle cannon plug. Pump starts. Just a minor amount of corrosion on a pin in plug. Good luck...
Had a new tech struggling to diagnose no power to fuel pump.
Told him to wiggle cannon plug. Pump starts. Just a minor amount of corrosion on a pin in plug. Good luck...
#3
Registered

Joined: Nov 2009
Posts: 4,198
Likes: 500
From: KY
Starting a new thread as the other one is 6 years old. 1997 Gen VI 502 mag MPI. It sat for 2 months at the marina and fired up no problem to bring home. On the voyage home, Stbd engine died and I restarted it no problem. Got home and tried to flush it, no power to fuel pump. Things I have tried: swapped fuel pups, fuel relays, ECM's, ignition switches, good voltage, bench tested the fuel pump. In the other thread it mentions a pink wire going to the fuel relay, I unwrapped the wire to the point it makes the bend forward towards the ECU. Im out of ideas. I can hear the relay clicking when I turn the key to ON but no buzz. I can recycle the key and got it to wake up on about the 20th try....then nothing again. Good battery voltage and it cranks fine. Im thinking a short or bad ground. Could it be something stupid like a bad connector to a Tach or Volt gauge? Thanks.
Key turns ON and MPR (Main Power Relay) energizes, gauges light up - good
The fuel pump turns ON by the ECM applying a ground to the FP relay. My first guess is the ECM is applying a ground but the FP relay is not energizing. You can swap the MPR with the FP relay, and if the FP relay is bad then gauges will not turn ON
#4
Thread Starter
Registered
Joined: Mar 2007
Posts: 121
Likes: 70
From: SW Florida
#5
Thread Starter
Registered
Joined: Mar 2007
Posts: 121
Likes: 70
From: SW Florida
I'm with you with these comments and also one other not mentioned
Key turns ON and MPR (Main Power Relay) energizes, gauges light up - good
The fuel pump turns ON by the ECM applying a ground to the FP relay. My first guess is the ECM is applying a ground but the FP relay is not energizing. You can swap the MPR with the FP relay, and if the FP relay is bad then gauges will not turn ON
Key turns ON and MPR (Main Power Relay) energizes, gauges light up - good
The fuel pump turns ON by the ECM applying a ground to the FP relay. My first guess is the ECM is applying a ground but the FP relay is not energizing. You can swap the MPR with the FP relay, and if the FP relay is bad then gauges will not turn ON
Like Velocity mentioned....I have not pulled the main cannon plug yet.



