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    351 VV hesitation on acceleration

    I'm having an intermittent hesitation problem with my '89 Crown Vic (variable venturi carb). Sometimes when I start out from a stoplight it hesitates and almost dies. It seems like a bad accelerator pump, but it only does it part of the time. Other times it works just fine, and I can go out under the hood with the car shut off, and when I pump it I can see gas squirting out into the bores.

    Is it normal for an accelerator pump to go bad intermittently, or do I just have a speck of dirt in it somewhere?

    Thanks in advance,

    Nathan in MN (now in MI for college)

    2001 Ford Crown Victoria P71 - "The Fire Engine"
    1985 Lincoln Town Car Signature Series
    But God demonstrates his own love for us in this: While we were still sinners, Christ died for us. Romans 5:8

    #2
    I'd check ignition/timing first, that sounds more the culprit. Its squirting so you should be fine. Might not squirt the right amount, but its squirting.
    Chris - A 20th Century Man \m/ ^.^ \m/

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      #3
      Do you have the throttle more than 70% down when this occurs? Mine does the same thing at over 70% throttle froma dead stop, but then it clears up. In my case, I think the mixture gets too rich and bogs the engine out. I've heard of similar problems with heavy, auto transmission cars with highway gears equipped with a carb.

      Accelerator pumps do go bad from time to time, especially if you used ethanol fuels.
      1990 Country Squire - weekend cruiser, next project
      1988 Crown Vic LTD Wagon - waiting in the wings

      GMN Box Panther History
      Box Panther Horsepower and Torque Ratings
      Box Panther Production Numbers

      Comment


        #4
        No, I'm just trying to start out at a normal pace in traffic. I know it doesn't like it when I floor it from a dead stop. That, as you point out, is to be expected. However, it shouldn't be happening at 1/4 throttle.

        As for the ethanol gas, I always just put in regular unleaded (87 octane). I think that does have a small amount of ethanol in it, though, doesn't it? I suppose that could conceivably harm things.

        Thanks for the advice.

        2001 Ford Crown Victoria P71 - "The Fire Engine"
        1985 Lincoln Town Car Signature Series
        But God demonstrates his own love for us in this: While we were still sinners, Christ died for us. Romans 5:8

        Comment


          #5
          E10 (the ethanol 10% gasoline mix that most states are using now) shouldn't hurt anything.
          Builder/Owner of Badass Panther Wagons

          Busy maintaining a fleet of Fords

          Comment


            #6
            It wouldn't be a bad idea to read you plugs to see if they are rich or lean.

            Have you completed a tune up on the car yet? A new O2 sensor could help, 7200 VV cars generally run rich when there is a problem with the O2 sensor or MCU.

            Does it rev fine parked, is it smooth running on the road?

            BTW, for GMN's entertainment for the day, someone on CVN suggested raditator leaks might be causing the issue...
            1990 Country Squire - weekend cruiser, next project
            1988 Crown Vic LTD Wagon - waiting in the wings

            GMN Box Panther History
            Box Panther Horsepower and Torque Ratings
            Box Panther Production Numbers

            Comment


              #7
              When was the last time the fuel filter was changed?
              86 Lincoln Town Car (Galactica).
              5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

              91 Lincoln Mark VII LSC grandpa spec white and cranberry

              1984 Lincoln Continental TurboDiesel - rolls coal

              Originally posted by phayzer5
              I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

              Comment


                #8
                Tiggie--I haven't done a tune up on it, but the guy that I bought it from replaced oil/filter, spark plugs, air filter, and he may have done cap, rotor and wires too. I can't remember. As for the O2 sensor, is there a way to tell if it's bad (i.e., a computer code or something)? I remember pricing one at the auto parts store and it was pretty expensive, so I'm not eager to replace it if I don't absolutely have to.

                It revs fine when parked and under cruising conditions it's perfectly smooth. It's only under initial acceleration that it makes the problem, and then only intermittently.

                Gadget73--I don't know about the fuel filter. The VV cars have the filter inside the carb, is that right? If so, is it difficult to change or is it something I can do in a few minutes?

                Thanks,
                Nathan

                2001 Ford Crown Victoria P71 - "The Fire Engine"
                1985 Lincoln Town Car Signature Series
                But God demonstrates his own love for us in this: While we were still sinners, Christ died for us. Romans 5:8

                Comment


                  #9
                  Fairly sure the filter threads on the side of the carb where the fuel line attaches. Should just need a couple line wrenches to pull it off and swap it. I don't know if they have a filter back on the frame rail where an EFI car has, but if its there, its on the passenger side right about at the back door. A quick look underneath will tell you.
                  86 Lincoln Town Car (Galactica).
                  5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                  91 Lincoln Mark VII LSC grandpa spec white and cranberry

                  1984 Lincoln Continental TurboDiesel - rolls coal

                  Originally posted by phayzer5
                  I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                  Comment


                    #10
                    My friend had a problem with his O2 sensor on his Crown Vic. He just unplugged it and turned the car on to see if it was bad. Just make sure you check the other sensor (the name of it escapes me at this point) before buying a new O2 sensor.
                    1982 Crown Vic LTD.
                    Pwr Windows
                    Shag carpeting
                    Pristine Vinyl
                    wood dash
                    5.0 302
                    Creme colour
                    Foreign Hub caps
                    Lots o' Rust!

                    Comment


                      #11
                      What kind of "other sensor" are you talking about? I know you said you couldn't think of the name of it, but I was hoping maybe it came to you.

                      If I unplug the O2 sensor, how will it affect the way the car runs if it's bad or good?

                      Thanks,
                      Nathan

                      2001 Ford Crown Victoria P71 - "The Fire Engine"
                      1985 Lincoln Town Car Signature Series
                      But God demonstrates his own love for us in this: While we were still sinners, Christ died for us. Romans 5:8

                      Comment


                        #12
                        It will probably start overloading fuel. The MCU unit tends to go super rich when there is a problem.
                        1990 Country Squire - weekend cruiser, next project
                        1988 Crown Vic LTD Wagon - waiting in the wings

                        GMN Box Panther History
                        Box Panther Horsepower and Torque Ratings
                        Box Panther Production Numbers

                        Comment


                          #13
                          Update!!!
                          I had trouble getting it to start this morning, so I took the air cleaner off and pumped it a few times, and not a single drop of gas came out. Looks like it is accelerator pump after all. Probably just a little dirt in there.

                          Looks like I'm gonna have to spend the afternoon with a bucket of carb cleaner. My dorm room should smell very interesting for awhile...

                          Thanks to all who offered their advice!

                          Nathan

                          2001 Ford Crown Victoria P71 - "The Fire Engine"
                          1985 Lincoln Town Car Signature Series
                          But God demonstrates his own love for us in this: While we were still sinners, Christ died for us. Romans 5:8

                          Comment

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