Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Speedo 4/4 2011 model

My vehicle has only covered 7000km in 12 years. On starting the engine I noticed that the digital speedo is registering 110 kph and the distance travelled has jumped to 22000km. Has anyone experienced this? Have always considered speedos to be indestructible. Is it the speedo or is it somethings else?

The speedo around that time works on electrical pulses as far as I know. My 2005 gets the twitches sometimes, and on an odd occasion at high revs the tacho spins fully round and bounces off the stop.

When my battery failed and I jump started off a battery pack, the speedo was all over the place standing still. A new battery fixed it. So check battery condition first. Make sure its fully charged, because the speedo is clearly voltage sensitive.

The only other likely culprit is a bit of damp, which should clear over summer.

Iain, I assume when starting you have paused after the first “click” and let everything reset (tachometer vibrates etc) before engaging the starter second/ third click. When I 1st got my car. New the speedo had to be changed as it was reading 130 at 30. So if the reset doesn’t work you may be in for a new/ repaired one.

A bit strange the odometer changing. There is a calibration a procedure on the Caerbont website, that is for the speedo speed reading. You need accurately check how far you travel with one rev of the road wheel. I would check that the probe is still secure in it mounting hole (mine's in the front offside wheel). Ensure the when you rotate the road wheel the very small and dim LED on the back of the illuminates once per rev if I remember correctly, or was it 5 times per rev, instructions will clarify

My 2011 4/4 the speedo pick up is on the prop shaft near the g/box. You can see the sensor etc (not sure what you call the rotating bit that the sensor picks up)

Reluctor?

Thanks Richard. New word for me.

Iain, You say that it does this on starting. Does it then stay like that whilst the engine is running, or does it revert to normal either after a few minutes or when you drive off?
Two possibilities come to mind: These instruments can be a bit voltage sensitive and as the car isn’t used much, could it be that battery volts are down, exacerbated by the electrical current consumed from starting?
Another thing I would try is to drop the dash board and check connection of all the wiring plugs, which can sometimes become loose, especially if they were not originally put on properly at the factory. (my loom behind the dash was an absolute mess!)