Speedo problem

[David Pickford]

hi everyone,

The speedo on my Atom 2 (2005 car) isn't working properly... The needle start to 'float' under acceleration / braking, sometimes going wildly up and down. It keeps an accurate reading sometimes at a steady speed, but most of the time it doesn't.

The SPA dash is new as of August, so it's definitely not a dash issue.

Any help with what I need to do to sort this out would be much appreciated. 

Thanks,

David

[dc5ian]

check the engine loom, where it goes into the ecu. you might have a poor connection

[Monza]

Check the magnet bonded to the driveshaft and the speedo sensor in particular the wiring on top.

[Steve Gibson]

Does sound like the magnet or the sensor. I had a very similar problem on my 2006 Atom 2.

[dreamscape]

Sorry for being slightly off topic, though I have a similar issue right now, after I have replaced the original SPA miles dash on my AA2 300, with a dash form a AA3 with display of speed in KmH.
Funnily enough the speedo works fine up to 190 KmH, than suddenly the needle goes back to 0 and remains there until the speed drops below 190 KmH again.
However this issue had never occured with the old SPA dash?!
Any advice???

[wasp]

Is it possible that the wire that carries the info from the sensor has got damaged or deteriorated in some way?

Possibly vibration or a slight surge is causing the information from the sensor to be continually interrupted.

Cheers,
Stu