Fuel pump noise

Lincoln Mark VII

  1. Elessee

    Elessee Well-Known LVC Member

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    1988 Mk7 LSC. My fuel gauge has been a problem so I keep the tank filled. Recently I take a 300 mile round trip every week, over the mountains, filling it before I leave.
    At 20 MPG, the car's range should be around 400 miles, but I stop for gas and fill it on the return trip, just to be sure. One time I didn't stop, and made it home alright.

    Then something weird happened. I was carrying extra cargo, and running fast up the hills. On a steep incline it sputtered, slowed, and felt just like it's out of gas. I carry a 2 1/2 gallon spare tank.

    I pulled over. Car is idling at the side of a quiet road. I get the spare tank out of the trunk. Standing out there, I hear like a whining or grinding coming from the back of the car. I start to pour gas into the tank, and the whine stops. It's the fuel pump? It's running dry?

    Cutting to the chase, I find someone willing to give me 5 gallons of gas at a tiny town general store... nice people! I drove a good 40 miles of steep mountain (12 MPG) on that 5 gallons plus my 2 1/2 gallons.

    Here's the kicker. I filled it up today. Today, there should be about 4 or 5 gallons left in the tank. I should be able to put over 15 gallons into my tank. But it doesn't accept that much. It's filled after 10 gallons. The 22 gallon tank had maybe 10 gallons already in it.

    According to that, I didn't run out of gas in the mountains. Can the fuel pump run dry when climbing hills? Do they get old and tired?
     
  2. OldSchool1

    OldSchool1 Dedicated LVC Member

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    The sound is normal but what you PROBABLY heard was the sound of unused fuel being pumped BACK into the tank through a red rubber anti-siphon valve.
    DSCF3999.jpg
    Low? Yes, hence the sputter or feeling of lack-of-power.
    Dry? No :) Engines don't run when tanks run dry :)
    Yes BUT, our Lincoln Mark VIIs will start to suck air while driving DOWNHILL before they suck air driving UPHILL.
    Everything eventually gets old and tired my Friend.
    "When in doubt, change it out."
     
  3. Elessee

    Elessee Well-Known LVC Member

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    Strange noise. Since it stopped immediately when I put a little gas in, I attribute it to the fuel system. If the noise didn't stop, I might write it off as an exhaust rattle.
    ...need to study this fuel system before doing anything. Maybe a filter, or injectors? Maybe the computer sensed something was wrong going up the hill, and it executed some weird code..?

    I'm certain there was a few gallons of gas still in the tank. All the dashboard electronics seem to be operating properly now. The tach works with the headlights on. Lighting is fine.

    When I jumped in the car to get gas yesterday, the gauge read a little less than half full. (?) That usually means about 7 or 8 gallons is in the tank (the gauge moves beyond the "full", so half a tank is 8 or 9.)
    I'm thinking, there's no way I can have anything close to 8 gallons. Fuel gauge must still be broken..
     
  4. OldSchool1

    OldSchool1 Dedicated LVC Member

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    LVC is a fantastic resource for all things Lincoln and Cadillac.
    For specific information concerning STOCK Lincoln Mark VII Fuel Systems, see The Lincoln Mark VII Club.
    The Lincoln Mark VII Club - Home
     
  5. Elessee

    Elessee Well-Known LVC Member

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    Far as i know it's stock.
    Elevation varied from 7 to 8,000 feet on the stretch of road, so it happened high up there. I'm flying uphill, and there's a few hundred pounds of cargo.
    The engine control is gonna lean the mixture up there. Combine that with something like a clogged fuel filter, and perhaps bad O2 sensors or other sensors.. pressure regulator...might it not starve for fuel?

    I'm working on the premise that it is fuel starvation. Tomorrow I'll plug in the code reader for the first time in a long time.
     
    Last edited: Nov 8, 2019
  6. OldSchool1

    OldSchool1 Dedicated LVC Member

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    Any testing is a step in the right direction.
    If you get to it before snow arrives, let us know.
    John "It's-November-In-Pennsylvania" Dancy
     
  7. Elessee

    Elessee Well-Known LVC Member

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    Nothing of interests came up in codes. EGR valve may not be functioning correctly. That could be an old one, from years ago.
    There's a stretch of about 50 miles where the Message Center says fuel economy is around 8 MPG. It's basically uphill at speed.... A lot of fuel is being delivered. This is where (twice) it "ran out of gas". A clogged filter could mess things up.
    I've never changed this fuel filter. They cost around $12. Autozone has it in stock. It's an easy installation. Youtube has a video. I think I'll do that, just for kicks.

    You ever hear of anyone pressure-testing a filter, to see if it needs to be replaced?
     

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