Scottish Elises

This morning on the way to work my speedo started jumping about it didnt matter what speed I was doing (went through the full range just to be sure:P) it seems to drop 20mph and then back up.

Idea's ?

Try cleaning the senor plugs contacts first then if thats no use replace the sensor. I have my old sensor here if you need to try it (not used on the honda).

Where is the sensor, rear wheel somewhere ?????

Does it return to zero when you're stationary?

Does it do the little <0 rattle off the end stop when you first turn the ignition on?

Does it ever read more than you're doing, or always less. If always less, even at speeds > TDC on the clock then I would say wheel speed sensor or wiring for sure.

If it reads more sometimes, especially at > TDC on the clock then the needle itself may no longer be properly connected to the spindle of the stepper motor.

Speed sensor is on left rear wheel - on S1 it routes straight to the dash from there; S2 goes via the ECU.

Cheers,
Robin

robin wrote:Does it return to zero when you're stationary?

Does it do the little <0 rattle off the end stop when you first turn the ignition on?

Yes

robin wrote: Does it ever read more than you're doing, or always less. If always less, even at speeds > TDC on the clock then I would say wheel speed sensor or wiring for sure.

If it reads more sometimes, especially at > TDC on the clock then the needle itself may no longer be properly connected to the spindle of the stepper motor.

It just jumps down then back up then back down etc.

robin wrote: Speed sensor is on left rear wheel - on S1 it routes straight to the dash from there; S2 goes via the ECU.

Cheers,
Robin

and Does it get you off any speeding fines ?

Sounds very much like a loose wire or dodgy sensor then.

Speeding fines? You would have to be speeding first Oh, and no, it makes your problem worse:

"How fast were you travelling, sir?"

"I don't know"

"(sharp intake of breath) That's going to cost you, ..."

Cheers,
Robin

na thats when you say "I was kind of hoping you knew"

BiggestNizzy wrote:na thats when you say "I was kind of hoping you knew"

LOL - or "If you don't know, I'm certainly not telling you!".

Speedo is working okay now, just spend the last 2 hours reconditioning the conector that goes into the sensor, as the wire broke just as it enters the connector

Ended up having to strip the connector apart prise open the crimped end reconect the wire and solder it together

Oh and blowtorches do not make good soldering irons

so where do I get a new connector for the wheel speed sensor ? I'm guessing its a standard off the shelf part

Try:

http://www.vehicle-wiring-products.eu/V ... mepage.php

Or:

http://www.simtekuk.co.uk/10271/info.php?p=6&pno=0

A lot of the connectors used on these cars aren't freely available, unfortunately.

Cheers,
Robin