Speedometer Problem???

[Crazy]

Bit of a wierd one this but here goes, for some reson when I turn the ignition on in my car the speedometer jumps straight upto 60mph :shock: and then when I start the engine it jumps upto 120mph but then comes back down to 60mph when the engine is fully started :shock:
Was leaving my car to idle and then noticed that the milage was clocking up even though the car was not moving :evil:
When I started to drive the speedometer then comes down to around 50mph but still the milage clocks up even if I am not moving, just dropped my girl off to her moms which is only 2 miles away and my milage has clocked up 19 miles and as soon as I pulled over the clocks go back to 60mph

Any ideas lads as this is putting needless miles on my clocks :?: :evil:

 

[ram5ay]

Could be faulty speedo converter box or dodgy wiring on the connections? Recon you are gonna have to pull the clocks out to see whatever. Might be worth disconnecting the speedo box and joining the wires back to standerd to see if all works ok in km per hour.