Crazy speedo

[jesse]

Hi all!
I have a strange problem with my Giulietta, -84, 2 liter. The moment I turn on the ignition the speedo goes crazy and runs all the way to max speed- The odometer ticks over accordingly. What might be the problem? Checked the wiring attached to the gearbox and it seems to be OK.

Cheers
Jesse

[Colin Edwards]

Probably the sender screwed into the gearcase.  Disconneect it and see what happens. 

Early transaxle cars used a rotary / mechanical pulse generator.  Later cars a hall effect based device. 

The sender has an internal oscillator.  Something has caused the sender to output high frequency impulses not proportional to road speed.  Try another sender and see what happens.

[carlo rossi]

short circuit in speedo
need to get it checked
mine starting to go same way

[Citroënbender]

Sure it's not a damaged earth?

[jesse]

OK, thanks fellows!
I`ll check the things you`ve mentioned. A new sender seems hard to come by, btw.