Jinma 284 tachometer ground wire

Forum Forums Tractor Troubleshooting Jinma 284 tachometer ground wire

Viewing 9 reply threads
  • Author
    Posts
    • #48351
      DavidPrivett
      Participant
        • Offline

        I think your best bet is to contact a dealer and see if they can help you out. They work on these everyday or close anyway. The only suggestion I have is to take a ohm meter and ground one lead  and with the other lead search for a zero or very close ohm reading and then trace it back to confirm that it is a real ground source. There is a possibility that the base of whatever you are looking at is grounded thru the chassis and all that is in the dash is the hot side , not requiring a ground there. But there will be a ground for the dash lights maybe you can figure it out from there. good luck

      • #48352
        Bob Rooks
        Participant
          • Offline

          A picture of the back of your tach would be extremely helpful.

          Your reluctor consists of a coil of wire around an iron core. Nothing magic inside at all. All it does is measure the difference in the magnetic flux field as a flywheel tooth passes by, and this difference is seen as a sine wave. The reluctor has two leads, it doesn’t matter which one is grounded. If the reluctor has one lead, then the body is grounded

          Account deleted.

        • #48358
          Raymond Hatfield
          Participant
            • Offline

            Both are good points and pretty much what I figured. I am not sure why some of my pics load and others don’t as they all come from my phone. The gauges are separate & not in a unit assembly. And they are all installed in the fiberglass body so they are not body grounded. There has to be a ground connection at some point. Also, the needle is not on zero and affordable said the tach needs power to reset it to zero but that does not tell me where the power comes from or goes to. Common sense would dictate the hour meter power source, but again you still need a ground for a complete circuit. The sensor is 2 wires which would give a voltage across the wires and the one side could be grounded.

            Attachments:
            You must be logged in to view attached files.
          • #48360
            Raymond Hatfield
            Participant
              • Offline

              Ok, I know that is not the best pic of the tach but it at least posted. Now I will try the schematic.

              Attachments:
              You must be logged in to view attached files.
            • #48362
              Bob Rooks
              Participant
                • Offline

                You are correct. The bottom right terminal post (K) is for the light.

                The center post (G) is for all ground connections. This must also be grounded to the engine/chassis.

                The left post (S) is for one of the leads from the reluctor, the other connects to the ground. These two wires are probably siamezed in a sheath. There should only be one lead connected to the (S) post.

                The red lead is the 12v+ feed from the fuse block and it also powers all the other gauges. It is fed from the key switch.

                Account deleted.

              • #48363
                Bob Rooks
                Participant
                  • Offline

                  When you turn on the key switch you should have power at the red wire. If you don’t then you have a blown fuse. This is assuming all the ground connections are good and clean.

                  Account deleted.

                • #48365
                  Arthur Ordoyne
                  Participant
                    • Offline

                    Thanks guys I hope this works

                  • #48366
                    Raymond Hatfield
                    Participant
                      • Offline

                      That’s where I stand on it. Hopefully I can look into next weekend. I swapped out the switch, and I changed the wiring to add in a relay for the glow plugs and bypassed the faulty clutch switch, so I will have to trace wires again. I got my Chinese photo tach for a comparison when I get the tractor tach going.

                    • #48368
                      Raymond Hatfield
                      Participant
                        • Offline

                        Tachometer is working, at least it’s reading and probably pretty close. It was the red +12V wire, that had no power.   One by one it’s coming together.

                      • #48371
                        Bob Rooks
                        Participant
                          • Offline

                          The middle terminal post must also have a ground wire to the chassis or another good ground source.

                          Account deleted.

                      Viewing 9 reply threads
                      • You must be logged in to reply to this topic.