No power to fuel pump on 1994 4.3L V6 Mercruiser

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Beachnutts

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Oct 3, 2008
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Re: No power to fuel pump on 1994 4.3L V6 Mercruiser

Don,
Thinking about when I started to listen to the pump, I remember now that this pump is slightly newer than OEM. The original pump failed when the boat was about 2 years old. The dealer replaced it under warranty, probably in '97. I had forgotten all about that. Didn't the 4.3L have an EFI option by then? Perhaps the dealer used a pump for an EFI system as my replacement? I'll have to look at the part number on the pump and look it up.
-Mike-
 

Don S

Honorary Moderator Emeritus
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Re: No power to fuel pump on 1994 4.3L V6 Mercruiser

The EFI pump and/or a carbed pump ONLY comes on when something puts power to it. It does not have a mind of it's own. The ECM on an EFI engine runs the pump for 2 seconds to build fuel rail pressure to the injectors. The ECM controls that. There is absolutely nothing that will run that pump for 2 seconds in a carbed system. Your system is identical to the wiring diagram I posted earlier.
 

drrm123

Petty Officer 2nd Class
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Oct 12, 2007
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135
Re: No power to fuel pump on 1994 4.3L V6 Mercruiser

maybe noise your were hearing is when fuel line was empty and once full pump would quiet down. you said purple-yellow wire went into harness it has to come out somewhere. you can still look under dash for fuse panel and see if you see puprle-yellow wire, i'd check all fuses both sides, like you said if dealer could have done anything, i'd check purple wire on back of alternator or at solenoid for voltage. if you can use your DVM to check ohm from both ends of p-y wire you can find. other than that you could get a test light and probe wire till it wont light and that's where trouble is at, i'd do that as a last resort.
 

Lexylomio

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May 8, 2013
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Re: No power to fuel pump on 1994 4.3L V6 Mercruiser

My mechanic just changed the starter on my 4.3lx alpha1 and now he says the fuel pump its not working or it won't turn on, on your post you asked the guy with the same problem if he changed the starter lately, what could be the problem with that?
 

Don S

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Re: No power to fuel pump on 1994 4.3L V6 Mercruiser

Welcome to iboat Lex, you need to start a new thread with your question as noted by the red warning bar at the bottom of this thread suggested.
 

WrenchNhammer

Seaman
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Jul 11, 2021
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Running into the same issue. I’ve definitely heard it run with key on. Mine no longer is, and when engine revs up past 2k it bogs down. It pumps for sure with engine running,but is it enough?
 
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