Intermittent fuel pump on mpi
#1
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Join Date: May 2017
Location: Harrison Twp Michigan
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Intermittent fuel pump on mpi
My port engine is not firing the fuel pump when I turn on the ignition intermittently. The engine cranks but won’t start when this happens. When it does fire the pump, it starts and runs fine. Anyone here have a similar experience? Wondering what the fix might be- relay or new pump? Any tips would be appreciated it’s an 02 454 mag Mercruiser. Thanks!
#5
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pull the fuel pump relay and look at the spade lugs of the connector,,see if they are over heated,also look at the bottom of the relay.merc went from thin pins to wider pins.
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I just had this issue on my 502 MPI. Marina replaced the main power relay ($40 - easy to get to on top of the motor). Thought that fixed it until I took it out - hit a good sized cruiser wake and motor shut off. Turns out if was a 10 or 15 amp fuse (forget which) that had a fractional break in it (fuse was in the same area as the main power relay). Both items are super easy to check.
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Fuse
I just had this issue on my 502 MPI. Marina replaced the main power relay ($40 - easy to get to on top of the motor). Thought that fixed it until I took it out - hit a good sized cruiser wake and motor shut off. Turns out if was a 10 or 15 amp fuse (forget which) that had a fractional break in it (fuse was in the same area as the main power relay). Both items are super easy to check.
#8
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Check fuse holder also for corrosion and tightness of the fuse itself in the holder. Also check the power wires into the VST if you have one as well as the harness connector for it. If it winds up being the fuel pump in the VST, sourcing one here is much less expensive than OE the last time I looked ($80) https://speedncustommarine.com/