LT77 speedo sensor

[FFMan]

As my speedo stopped working a while ago I finally got round to dropping the exhaust so i could remove the sensor/drive.

With a meter i could find no continuity or output from the sensor at all. On the car wiring side I found +12v and a 0.3v signal when the ignition is on. Spinning the drive with a drill with the ignition on, connected to the car produced no reaction from the speedo - i think the drive/sensor is duff.

The drive cog of the sensor is orange and has 20 teeth, Rimmer have something listed but not sure if they have stock. Anyone know of any other sources ?

thanks


Edit - i see TVR-parts have one for £105 but any other sources ?

Edited by FFMan on Tuesday 27th December 20:25

[FFMan]

Sadly Rimmer have no stock of the sensor.

I note that there are 4 pulse and 8 pulse versions, i think even if you have the same number of teeth on the cog.

Is there a way to know/tell which I have - there doesn't appear to be any part number on my part at all.

[Hoover.]

The cost of the speedo sensor may seem high, if you want you could look at the transducer (the metal box at the end of the cable)and see if there is a part number on there and get just that from a LR dealers (I'm guessing would be circa £60)

Quick scout the round the internet shows that the orange 20 tooth drive is not easily available.... when I had an LT77 box you could not source them unless you were in the business........ your 20 tooth drive is now approaching 25 years old, how much longer will that bit of plastic/nylon last ? I'd garb it while you can but that's just me

[griffdude]

Yes but on the plus side, it keeps the mileage down

[FFMan]

Have emailed my mate at Unipart - might be some secret stock...

[Hoover.]

I'd take a punt on 4 pulse option, as this is what TVR car parts are selling

[griffdude]

Just taken my dash out today to fit one a newly laminated item- found all sorts of horrors. But it might be of interest to the OP I found the speedo earth wire was barely connected. Just a thought.

[Barreti]

I remember this being discussed a few years ago now so I looked for an orange toothed sender to keep as a spare but couldn't even find one.
If anyone does find one at a decent price then grab it.
If you find a few let me know!

[FFMan]

Having pulled the sensor from my car it was unclear if mine was 4 pulse or 8 pulse, so I dismantled it, and from the internals it looks like 4 pulse.

In doing so, i discovered lack of continuity in the yellow wire to the PCB, so i repaired this and araldited up the cable entry/exit point and will test it on the car tonight once it has all set fully.

I saw a post elsewhere with a similar fix effected without full dismantle, seems like a commonish problem area.

[FFMan]

so my repair to the broken wire seem ok on a test with a drill under the car.

Will refit and road test ASAP.