Speedo stopped working…

[Riff Raff]

After some advice. On the way to a local garage to have the oil and filter changed I noticed the speedo wasn’t working. It had been working the day before. When it was in the garage and up on the ramp I asked them to check over the wiring for the sensor at the diff. The wiring looks OK.

So, the question is what to do now? Is it worth pulling the dash top off to check the wiring behind the gauge? Do the instruments themselves ever fail?

Or do I just take the sensor at the diff out and give it a clean?

Suggestions for the quickest and cheapest way forward welcomed.

[Riff Raff]

Steve_D said:

Do you have RoverGauge? If so plug it in and go for a drive. It will not show the true speed and will probably read about 35mph.
If you do get a reading then the sensor is working. That leaves the speedo itself or the connection between the speedo and TVRs 'black box'. Or the black box itself which is less likely.
The speed signal from the sensor is not compatible with the ECU so TVR fitted the black box. It just reads the signal and just tells the ECU 'we are stopped' or 'we are moving (35mph)'. I doubt the 'box is an issue as the signal goes straight through.

Steve

Thanks Steve. Unfortunately Rover Gauge won’t do me any good, as the car has one of Dom Tricket’s MBE ECUs. Maybe I should give him a call, as the car is partially rewired as part of the conversion process, and I’m not even sure it still has the black box.

Blitz’s suggestion looks like a quick way to tell if the sensor is shagged. I’ll see if I can give it a go getting at it on axle stands.

[Riff Raff]

So, thinking about the MBE, it has an OBD port. I should be able to see a speed signal on that. If I can get hold of a reader!