Speedo has gone erratic

[michaelc291]

On my 1994 XJ RHD my speedo has sometimes started jumping up to 80kmh irrespective of what speed I am doing. (It came with KM/H rather than MPH). Sometimes it is fine.
If I continue to drive with it stuck at 80 it may suddenly start to give the right reading. The needle is steady and does not flap about like the old cable driven ones did sometimes.

To be honest I am not sure if it is mechanical or electronic, though my bet is electronic.

Has anyone had this problem and what can be done to sort it?

If I have to find a second hand head, how can I clock it to match the car's original mileage? The mileometer (odometer) is mechanical.

I'm looking forwards to your suggestions. Thanks all. Mike.

 

[JPNinPA]

Have you ever replaced the speedo gear? If the gear is not seated or clocked right in the housing you could end up with chipped or mushed teeth.


Regards,
JPNinPA

Sent using TapTalk

 

[mark sr]

I don't know for sure but I'd be inclined to think your speedo is cable driven. You have to disassemble the speedo to reset the odometer. I've done it before but it's been a long time ..... and technically it's illegal.

 

[michaelc291]

Thank you for the suggestions. I looked at gears on the net and there seem to be dozens to choose from. Why are there so many?
I think I'll get underneath and see if it has a cable or a sender attached. I agree about clocking the clock but is just from my convenience and to keep it right on the test cert. (just don't tell anyone).

 

[JPNinPA]

So many? : to cover/correct all gear tire size combinations that result in different speed and odometer readings.

Oh and being you told only me on an open forum. I’ll keep it just between us.

Sent from my iPhone using Jeepz.com mobile app

 

[JPNinPA]

Just another thought. Dash board connector behind the dash. It Often loosens causing various errors.


Sent from my iPhone using Jeepz.com mobile app

 

[michaelc291]

Thanks again for the suggestions. As the weekend is coming I'll get the screwdrivers out. If I need a replacement head has anyone got one they would part with (for a small fee)?

 

[JPNinPA]

Verify what engine you have. You might also post in the swap meet area with an appropriate title. Click bait


Regards,
JPNinPA

Sent using TapTalk

 

[michaelc291]

Things have taken a turn for the worse. After my last post things went back to normal so all was good. The other day I pressed the trip reset button and it stuck partly reset. I pressed it a few more times but did not manage to get it to reset. What has happened now is the the main mileometer (odometer in American) has also stopped working.
My thoughts are that there is some sort of mechanical failure in the cogs that rotate the thing. The actual speedo part still works but sometimes still sticks at 80.
I think I will definitely need a new speedo head now.
Are there any suggestions that could be useful?

 

[TerryMason]

If the odometer is broken, then I'd start looking on ebay for one that has about the same mileage as yours

They appear to be relatively cheap:


https://www.ebay.com/sch/i.html?_fr...+1994&LH_ItemCondition=4&rt=nc&LH_TitleDesc=0