Speedometer Stopped Working!

Zoetoes

Help!

I was driving home yesterday and my speedometer stopped working, is it fixable?

ts_aly2000

Good question. Is it a car? How old is it?

If it's a 1988 Fiesta then yes, a few quid. But if it's a 2001 Audi TT, wellll, let's call it a grand.

Zoetoes

Yes it's a car, 1997 Fiesta lol

ts_aly2000

zoeleigh wrote:

Yes it's a car, 1997 Fiesta lol

Oh that'll be cheap then. Might even be a cable.

There's two ways they do it. The original and older way is to have a solid rotating cable (bit like a bicycle brake cable) go into the back of the speedo. A rotating arm sits inside a disc thing and centrofugal force causes the needle to go up. Or something a bit like that..

In newer cars. They have a magnet on the flywheel, and a hall effect sensor (a coil of wire) which is energised each time the magnet goes past. These 'pulses' are fed to a computer in the car, and gfuhslrjghlgsh, somewhere along the lines you end up with your speedo telling you how fast you're going. This approach also enables all these mpg calculators and alike since it's all so computerised.

So then, if it's a 1997 Fiesta then you should be fine The later computerised speedos are an absolute nightmare to diagnose and fix, since nobody actually really knows how they work, apart from an engineer in Germany called Herman. Ask any garage, or anyone that's had these kind of problems. Herman was no where to be found, and the garage management keep on insisting they've met him and that he passed on his knowledge last time he was there.

pianeet

you could always buy a cheap gps speed camera detector like the original road angels as these give you your speed should get one for about £30 on ebay

Mikeyorks

Only time that's ever happened to me - the little flat drive shaft had come out of the recess at the back of the speedo. Owing to the nut holding the cable end in place, having loosened. So, hopefully, it might just be a cable - or, even better - just tightening the nut again.

ts_aly2000

pianeet wrote:

you could always buy a cheap gps speed camera detector like the original road angels as these give you your speed should get one for about £30 on ebay

It'll fail an MOT without a working speedo. If the equipment is fitted it has to be functional.

pianeet

ts_aly2000 wrote:

It'll fail an MOT without a working speedo. If the equipment is fitted it has to be functional.

they do not check your speedo for an mot,your car never leaves the garage
i have mot,d two cars in the past with broken speedos,and both have passed

tomstickland

The car is run on rollers to do the braking test during an MOT.

Anyway, should be simple to fix. If it's mechanical drive then either cable is knackered, or it's fallen off the back of the speedo. If it's electrical will be bad connection or knackered wire probably.

ts_aly2000

pianeet wrote:

they do not check your speedo for an mot,your car never leaves the garage
i have mot,d two cars in the past with broken speedos,and both have passed

I think you should tell that to these people. This appears to centre more around the milage being recorded than the speed being reported. There's many more examples all over the net if you look;

http://www.motester.co.uk/motquiz.html

5. Your odometer failed when it registered 45063 miles, which was just after the last MOT. Would that result in an MOT failure?

a) No, because the odometer is not part of the MOT.

b) Yes, because the odometer must be working to record the accurate mileage for the MOT.

c) Yes, because the odometer is connected to the speedometer, which must be working for the MOT.

Zoetoes

Thanks for the replies, got someone having a look at it today, it is a cable.

I've got a sat nav with a speed camera detector in so I could have used that in the meantime.