Fuel pumps not running, no spark either

shempest

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May 6, 2020
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1998 7.4GiPBYCCE Ser no. 4110158142
Had boat idling the other day and engine stopped. Attempted to restart and noticed fuel pumps not running.
Have bench tested as good both ignition and fuel pump relays.
Checked for power on fuel pump socket pins 30 and 86. Both had power.
Checked power on ignition relay socket pin 30 had power.
Jumped pin 30 to 87 on fuel pump relay socket and pumps both run.
Replaced relays and bumped ignition; fuel pumps did not run.
Removed relays and checked ignition relay pin 86 with ignition on had power.
Curiously, rechecked other pins, had power at fuel pump relay pin 30, but no power at pin 86, also now no power at ignition relay pin 30. Still had power at ignition pin 86 with ignition on.

There is power on both sides of all three engine circuit breakers by main plug (50, 12.5, and 50 amps) and fuel pump circuit breaker.

Engine safety kill switch appears operative; check that switch functioned open/closed at the harness connector under dash.

Thoughts for next step? Not sure what would interrupt power to fuel pump pin 86 and ignition pin 30.
 

alldodge

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Fuel pump relay 30 and 86 are jumped together. Loosing power on one of them is either corrosion, broken connection, or voltmeter connectivity issue

Fuel pump relay pin 85 goes to ECM to apply ground which energizes relay

Ignition relay pin 85 goes to ground

Have you checked grounds?
 

shempest

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I'll check the grounds for continuity.
Pretty certain that the voltmeter connectivity is not an issue...
I can jump fuel pump 30 to 86 to see if I can bypass that problem, where does ignition pin30 get power from? Is it reasonable to jump it from fuel pump 30 as well?

Thanks for posting wiring diagrams on the 5.7 Gsi not starting, no fuel pump startup?​​​​​​​ ​​​​​​​ thread from May 2016; very useful stuff. [h=2][/h] [h=1][/h]
 

alldodge

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I would post more pics here but the site is messed up currently. I have to go find where I posted previous then link pic to new thread

Main power to all the relays come from the motor 50amp breaker. The Red/Purple will feed all fuses, then fuse to relay pin 30

Yes if you jump 30 to 86 this will send power to FP
 

shempest

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Thanks for all the advice. It was corrosion at the 12.5 amp ignition CB, where the pink wire that runs to pin 30 of the ignition relay attaches. Now to replace the frozen sea water pump!
 
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