Announcement

Collapse
No announcement yet.

Speedometer holds speed when slowing down

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Speedometer holds speed when slowing down

    Like the title says, as I'm slowing down the speedometer stays at the speed I was travelling for a while before starting to move down. I have verified it is not the vss as it does respond to changes in speed instantly. I'm thinking something with the motor that drives the speedo head. Anything I can do to fix this?
    This is in my 92 Grand Marquis.

    #2
    There should be a return spring in that thing, IIRC, and the motor fights it (it's not very strong, either of them)... so you may have a busted spring... or need to lube stuff.

    Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
    rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)

    Originally posted by gadget73
    ... and it should all work like magic and unicorns and stuff.

    Originally posted by dmccaig
    Overhead, some poor bastards are flying in airplanes.

    Comment


      #3
      where is the spring? I don't recall it fighting a spring because the needle goes wherever when not powered.

      Comment


        #4
        i think its actually magnetic coupled, no return spring on the electro speedo. Sounds more like lube issues if you ask me.
        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


          #5
          Originally posted by 86VickyLX View Post
          where is the spring? I don't recall it fighting a spring because the needle goes wherever when not powered.
          Like gadget said, no spring, it is electromagnetically controlled as far as I can tell which is why it behaves as you've seen when not powered.

          Could it possibly be the little power board at the bottom right of the cluster not reacting to the change as quickly as expected?
          I believe that board is responsible for controlling the speedometer.
          Click image for larger version

Name:	Crown-Vic-Speedometer.jpg
Views:	1
Size:	38.2 KB
ID:	1276680
          Vic

          ~ 1989 MGM LS Colony Park - Large Marge
          ~ 1998 MGM LS - new DD
          ~ 1991 MGM LS "The Scab"
          ~ 1991 MGM GS "The Ice Car"

          Comment


            #6
            I believe the board you described is for the gas gauge. WagonMan
            89 Colony Park
            90 Colony Park
            70 HEMI Daytona Convertible

            Comment


              #7
              Originally posted by WagonMan View Post
              I believe the board you described is for the gas gauge. WagonMan
              Looking at it some more...
              http://unitedpantherownersassociatio...22176#pid22176

              It looks like you are correct, that board may have nothing to do with the speedometer.
              Vic

              ~ 1989 MGM LS Colony Park - Large Marge
              ~ 1998 MGM LS - new DD
              ~ 1991 MGM LS "The Scab"
              ~ 1991 MGM GS "The Ice Car"

              Comment


                #8
                Its the anti-slosh module and the instrument power supply if I'm not mistaken. It powers the gas and temperature gauges. The older ones used a flukey mechanical make/break regulator, newer ones moved from the 1930s to the 1970s in terms of technology for voltage regulation.
                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


                  #9
                  Has anyone disassembled one of these? I don't see how it comes apart so I can get at the motor to lube it. I'm afraid to pull the needle off, because of the alignment of it as well. I had a bitch of a time doing it with my 86.

                  Comment


                    #10
                    you need to pull the needle off, but it's a BITCH to get off. my 93 was a royal PITA to pull off and it required using a pair of needle nose as a pickle fork to do it. Did that when I fixed the damn odo gears the first time. The real bitch of it all was finding zero again. The 93 vic speedo motor can actually be accessed from the back side if you're not removing it by removing the odometer stuff (again... PITA) and using a needle type of lube (or straw type spray) to get the lube where it needs to go. The second time I had to jack with that shit I just put in the digital speedo and said f#$% it!

                    Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
                    rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)

                    Originally posted by gadget73
                    ... and it should all work like magic and unicorns and stuff.

                    Originally posted by dmccaig
                    Overhead, some poor bastards are flying in airplanes.

                    Comment


                      #11
                      Originally posted by sly View Post
                      you need to pull the needle off, but it's a BITCH to get off. my 93 was a royal PITA to pull off and it required using a pair of needle nose as a pickle fork to do it. Did that when I fixed the damn odo gears the first time. The real bitch of it all was finding zero again. The 93 vic speedo motor can actually be accessed from the back side if you're not removing it by removing the odometer stuff (again... PITA) and using a needle type of lube (or straw type spray) to get the lube where it needs to go. The second time I had to jack with that shit I just put in the digital speedo and said f#$% it!
                      Do you have any pictures of where the lube needs to go? And also what type of lube do you recommend?

                      Comment


                        #12
                        I'd probably be using clock oil for something like that.
                        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


                          #13
                          I tried lubing it with oil for small motors like model oil. It didn't change. When not energized the needle moves fine. No issues. When energized and I move the needle the magnet promptly pulls the needle back when I let go of it. I'm wondering if the electronics that control the speedo head are to blame?

                          Comment


                            #14
                            starting to sound like it.

                            Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
                            rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)

                            Originally posted by gadget73
                            ... and it should all work like magic and unicorns and stuff.

                            Originally posted by dmccaig
                            Overhead, some poor bastards are flying in airplanes.

                            Comment


                              #15
                              Apparently not. The motor was a little dicked. Spin it by hand and it was making some pretty icky noises. Thain swapped the motor onto the 140 speedo board and we clocked the needle pretty much spot on. It now responds as it should. Thanks Thain!

                              Comment

                              Working...
                              X