Speedo Playing Up

[Guest GrantB]

I've got a VDO electronic speedo, which is obviously getting power to it as the needle periodically spins from 0 - 120mph and then back to 0 again, but apart from that, doesn't work. The numbers on the display appear 'broken'. Does this sound like a problem with the clock, or the pick-up?

 

Everything seems in place around the pick-up.

 

Would the clock just ask for information if the pick-up was damaged?

 

It's all white man's magic to me...

[Joel]

What sort of pick up is it and which part of the car does it read from?

 

For example, Is it a magnetic sensor with a reed switch reading from the propshaft?

 

Is there any possibilty it could have moved slightly?

 

I had similar erractic readings from mine when I was setting it up - the margin of error for the sensor detecting the magnet as it passes is tiny, slightly out either way is the difference between it working or not.

 

Having said that, even when the needle wasn't moving I still had normal reading on the digital display, so perhaps it's your guage.

[Guest GrantB]

Yes, the display playing up makes me think it is the clock.

Not sure about the type of pick-up or switch, but think it gets signal from diff (is that likely?), it's located around that area.

It didn't work when I bought the car, the previous owner said the pick-up had been knocked when it was on ramps, if that's true, it could just be out of alignment I suppose, but, like you said, the display should still be okay shouldn't it?

May try to get some 'setting up' info. Thanks Joel.

[Guest GrantB]

By the way Joel. Is that a 2B you've got there? If so, where did you get that grille?

[Joel]

Grant,

 

My pick-up is pointed at the diff/prop mating plate, so it's quite likely that yours could be there too. If you have a crawl under your car it should be quite obvious if it's broken through contact with a moving part, or simply out of alignment. I originally had mine reading from the propshaft - the prop hit the pick-up on my way to SVA and snapped it in half

 

Instant SVA fail :boohoo: and £30 for a new pick-up. Not impressed :gdit:

 

Anyway, a bit of investigation should eliminate a few possibilites. The only other thing I can suggest is to check you have a steady and constant 12V power feed to the clock and the pick-up.

 

Yes it is a 2B, and my grille is from Demon Tweeks (affectionately known as Demon Thieves in these parts, and for good reason).

 

Product Code: 77777A (JPE 7 nose cone grille), £31.82 +vat

[Guest GrantB]

Thanks for that Joel. Something for the weekend methinks.