Speedometer not working

[_ali]

Hi,

Since the weekend my speedometer has stopped working correctly - when the car is cold it reads 0mph until around 30-35mph, above which it is fine. Once the car warms up it improves, working from 15mph upwards. (Car is an S2 with sinclaire honda conversion if that's relevant)

Presumably this is an issue either with the wheel speed sensor or the connection to/from the ECU? Are there any common issues that I should check myself before sending it off to SLS?

Thanks
ali

[robin]

Sounds like a rear wheel bearing

On the S2 the ECU drives the speedo, so even when they do the conversions I think they leave the old ECU in to do this (and drive the temperature display).

It's worth checking that the ECU connector has remained water proof (not sure where they put the Honda ECU, and whether or not that effects the positioning of the original ECU rain shield).

Assuming it all looks OK you check continuity of the wiring easily enough by removing pax side wheel, ECU plug and checking the path from the sensor to the ECU (it's a VR sensor so there are two wires plus a shield, which is not connected to anything at the sensor end, but should be connected to earth at the ECU end).

In your case, either the signal is too noisy or the signal is too small. The latter sounds more probable given the symptoms, and if it isn't a corroded connector attenuating the signal, then it's probably just that the sensor gap is wrong. But I don't think the sensor gap is adjustable on an S2 as the sensor is an integral part of the rear bearing pack. Hence my conclusion that it's a rear wheel bearing

Cheers,
Robin

[Gourlay83]

As Robin Said, on S2 Honda Conversions the original ECU must be kept to drive the Speedo & Temp Display. You only connect up a few wires so its not too difficult to check. If your Temperature Display is working then there's a good chance its all ok.

I had a little trouble with my Speedo (S1 Honda) when i converted my car, caused by the Gap in between the Sensor and Pulse Ring. I removed ithe sensor, cleaned all the crap of all the surfaces and its worked fine ever since. There is a tolerence for the Gap in the manual (can't remember of the top of my head).

but if it can't be adjusted

Best of Luck
Alan

[_ali]

Thanks Robin and Alan.

The rev counter and stack temp display are working fine, so presumably that means the problem is either at the wheel bearing/sensor or between there and the rover ecu?

cheers
ali

[robin]

Yes, but it's a Lotus ECU not a Rover one on the S2's. Also the rev counter is driven by the Honda ECU not the Lotus one.

Cheers,
Robin