speedo sensors

[JonyTVR]

I know this gets brought up quite often but I cant find any threads regarding moving it to somewhere else at all.

basicly I have a 430 with the SD1 box, now the bible says it should be located at the gearbox end of the prop but after getting it up on the ramps at TVR POWER I find its right at the back behind the exhaust/chassis/diff and is impossible to see the gap between the sensor and the toothed wheel.

now has anyone ever moved it to somewhere abit more accessible? and what's the best way for testing to see if the sensor is actually duff or not as it was only replaced a year and half a go by Track V Road and has barely done 1000miles since. I bought it not working so I don't know how it failed whether it was gradual or all of a sudden.

any help appreciated!

[JonyTVR]

anyone?

[TV8]

I had mine changed recently and apart from adjustment, I think it either works or it doesn't. The labour was more than the part from recollection.

[Tyre Tread]

As far as I know, all of the speedo sensors run off the diff cogged wheel.

It's not possible to test the sensor (transducer) without specialist equipment (Oscilloscope).

It's possible that th transducer has been killed by coming into contact with the toothed wheel. Take it off and look at surfca e and se if here are any signs of damage

For the price of a transducer you can buy Steve Heath's speedo kit which has several advantages.

It has a much more sensitive sensor, which means it can be positioned further from the trigger wheel, with a built in LED so you can see if its working.

The kit comes with a short loom that plugs in behind the speedo and incorporates a test box with switch which produces a test signal to the speedo head so you can be sure that is working.

Mine failed and I was about to buy the replacement transducer. I'm glad I didn't because it turned out (afer diagnosis using Steve's kit) that the Speedo head unit is kaput and I sent it off to (not so) Speedy Cables at the weekend.

[TJC46]

If it has been knocked out of position at all it wont work. I stripped mine off its mounting during a bodyoff refurb.When i came to replace it i measured the gap between sensor and teeth on the diff,as per bible, tried it and it didnt work. Frustrated i put the car on axle stands and tried various positions [neare in. further away.] each time actually running the car to see if it was working. Eventually i found the correct gap [whatever that is] and the speedo now works fine.Yours may be broke but even with a new one you have to mess around a bit to find the optimum gap. Try the above first before you spend £60 plus on a new sensor.