road speed sensor

[Milk Tray]

I need a road speed sensor for the early sd1 type gear box, does any one know where I can source this? I have been looking for ages but can not find one

[Geoff38]

Hi , i have been searching too with no luck , there is one on ebay now but how do you tell if it is the 8 pulse type ? wrong plug on it as well. I may go down the route of trying a 4 pulse one as they are still available from rimmer bros and putting a correction circuit. I have just brought this and need to build it and get the transducer to try it out.

http://www.jaycarelectronics.co.uk/productView.asp...

[Barreti]

Have you seen this thread?
Clicky

[Geoff38]

Hi , yes I think that was where I found out about the correction circuit. I would rather not replace the speedo as I like the "upside down " one. If My route does not solve the problem then I am going to do a complete chassis swap sometime in the near future as Mine is rotten and the rolling chassis I managed to get has the later BTR diff with the sensor on the drive shaft so will use that and then sort out which speedo I neeed to use ( or get mine made to suit the new style sensor )
Cheers
Geoff

[Milk Tray]

I have spent an age searching but no luck as yet. It is a shame because the sensor itself is fine, its just the wires have broken off at the base of the sensor so I can not fix it.

[Geoff38]

all you need to do is remove the plastic around the wires to give enough free to solder them wires back together , seen a thread about this somewhere in my search , might be V8owners forum , will try and find it again.

Ian , in the other thread You mention that You tested the sensor on and off the car , please can You explain how. I had go at this with an oscillascope and could see a 12v dc appear when the ignition was turned on but no pulses when spinning the plastic gear. We took it out and put a dvm on it to measure continuity and saw that when slowly turning the gear there were 4 distinct "open/closed" changes . We know the sensor is the wrong style as the wires had been cut and new sensor soldered on to the plug.( wires don't match - plug has brown and yellow/black whereas the sensor has brown and yellow )

edited to add link to fixing sensor , yes it is a real link , ignore the fact it has vintage airplane in it

http://www.vintagemodelairplane.com/pages/Snippets...

Edited by Geoff38 on Sunday 29th July 10:10

Edited by Geoff38 on Sunday 29th July 10:14

[Barreti]

Yes, as Geoff says, there is a "how to" on replacing wires.
I'll see if I can find it.

I tested mine with it re-connected underneath the car.
It was much easier with it removed from the gearbox, I just had the sender in my hands and spun the end. It quickly showed up to 30mph on the speedo which Mrs B was sat watching for me.

Testing with it reattached to the gearbox was harder.

The back of the car was jacked so both wheels were off the floor (all usual caveats about jacking safety apply obviously) and with Mrs B stood outside the car watching the speedo I spun the back wheels by hand. It was difficult to register even 5mph but it looked OK.

I haven't had a problem since refitting mine yet.

Edited by Barreti on Sunday 29th July 10:17

[Barreti]

Got it
Here

[Geoff38]

just edited my post to add the link too

[Milk Tray]

This info is much appreciated, I hope I can fix the sensor it is worth a go.

[Geoff38]

Thanks for the testing info Ian , mine would not register on the speedo or the ecu reader ( says "stopped" in the relevant reading )
I have emailed Caerbont Automotive Instruments Ltd. as they were mentioned in the other thread , may come to nothing but got to try>

Cheers.

[Barreti]

Is your transducer the same type as mine Geoff?
TES 2805 / 2001

I'll help search if it is, because if I find one I wouldn't mind one as a spare.

[Geoff38]

Mine has no marking stamped on it at all and it has never worked , previous owner/owners had been trying to get it working and they had swapped the sensor to this 4 pulse one , possibly not knowing that there were two styles.

[davep]

I've also been after a LT77 speed sensor but the closest replacement I've found is this Stewart Warner one:

http://www.summitracing.com/parts/SWW-82623B/?rtyp...

Might be worth asking CAI/Speedy if they can re-con sensors or convert 4 pulse to 8, it's only a simple Hall effect and transistor pulse generator.

The Jay speedo corrector self-build circuit is a useful bit of kit as it also allows for the accurate setting up of the speedometer after changes in rear wheel/tyre sizes.