2000 5.7 gsi fuel pump relay problem

[SD2600]

hi gang, I have a 2000 5.7 gsi that is having issues with the fuel pump relay...A few weeks ago i brought the boat home to clean it up for this years fishing adventures... I ran the boat on the muffs with no issue.

Today Im finishing up a few details and I attempt to start it on the muffs and my problem arises.
Typically i turn the key to the run position and I can hear the fuel pumps run for 2-3 sec... this time nothing..

when cranking the engine the pumps will not start.

Running jumpers from the battery to both the high and low pump they both run

with the key in the on position I have swapped relays that are located on top of the low pressure pump... facing the crank the rely on the right or port side has a positive click when inserted.. the relay on the left or starboard has no click

Any suggestions on where to start my trouble shooting?

Thanks

 

[dubs283]

Check for 12 + volts at lead #30 at the receptacle for the fuel pump relay

Check if there is a fuse for that lead that may have failed

 

[SD2600]

i will check the volts at #30 in the am.. it has a resettable breaker i believe 20 amp mounted right next to it that i will also look at... not sure how to text those though......

 

[alldodge]

What's your serial number?

 

[SD2600]

5.7gsi pwtr
4110195278
2868947

 

[alldodge]

Her is your main and FP relays
Ones the Main (item 14) turns everything ON, the ECM will apply a ground from J1-23 for a couple seconds to turn FP (item 1)

 

[SD2600]

i have 12v on both #30 pins...when i turn the key to the run position i can hear one of the relays click

 

[alldodge]

i have 12v on both #30 pins...when i turn the key to the run position i can hear one of the relays click

Measure voltage on pin 86 of the FP relay, it should show 12V and then go to zero for a couple seconds when ECM applies a ground, then go back to 12V

 

[SD2600]

 

[SD2600]

based on the pic above. pin 30 is on the left and pin 86 is on the bottom,,

the rely on the top has constant 12.28v on pin 30. pin86 has 0v with the key off 12.28 with key on

the rely on the bottom pin 30 has 12.28v and pin 86 has 12.28v with the key on or off

 

[alldodge]

I should clarify, was looking for power with replay installed, this way 12V on one side of the relay coil will show up on the other when a ground is not applied by ECM

With having 12V on 64 of the FP relay this means that pin 85 goes to ECM pin J1-23 instead of 86. It will work the same.

 

[SD2600]

Ok my numbering in the above pic is incorrect. 30 on the left or 9 o’clock position 85 on the bottom or 6 o’clock. And 86 on top.

Based on that, the relay on top is #14
And the relay on the bottom is #1 which is the fuel pump

 

[SD2600]

So if pin 86 on the fuel pump relay does not lose voltage for a few seconds when the key is turned on. My problem is the ground on relay #14?

 

[alldodge]

No, looking at 1 FP relay.
The coil inside the relay needs 12V and a ground to energize and pass current thru pins 30 and 87. If 12V is on one side of the coil but no ground on the other it will not energize. The ECM controls the ground to turn it ON. So with no ground supplied by ECM you should see 12V on either side of the coil. If 12V is not seen on both sides with Key ON, then relay coil is bad of fuse is blown

Relay 14 is Main power relay and it has a constant ground on Pin 86. When key is turned ON it supplies 12V to Pin 85 energizing the relay. The MP relay then turns the ECM and and everything else via the purple wire. The MP relay stays ON until key is turned OFF

 

[SD2600]

So my problem is the ecm is not supplying the ground to the fp relay…. Correct?

 

[alldodge]

So my problem is the ecm is not supplying the ground to the fp relay…. Correct?

Could be but need to verify first.
If it turns out no ground is being applied check the wire from ECM to relay

 

[SD2600]

The wire from fp relay pin 86 has good resistance to j1-23

 

[alldodge]

Are you seeing 12V on coil sides of the coil when ON?

 

[SD2600]

Yes

 

[SD2600]

With the fp relay slightly pulled out I’m gettin 12v on 85 and 86