Speedo device ain't working

[niallinireland]

Hey
Has anybody any experience of having problems with there speedometer?? The speed clock is not showing what speed i'm doing, when i'm doing 60mph it shows 40mph, and after about three quarter to an hour of driving the speedometer on the dash will start "waving" all the way down to 0 and stops working all together. Tried changing the dash display after getting one out of a scrap yard, new one did the same thing, so it has to be the measurement device. I know where it is just don't want to take it out and then find i cann't get it back in. Its an electronic device, right?? so i'm wondering is just a seal magnetic unit or something that will just unscrew and be replaced or fixed easily??

Thanks,
Niall in Ireland

[MattMU]

Niall, being your rig a 3.1l 93 model, then I would assume its NOT electric and a plain old cable speedometer. If in doubt, crawl under and disconnect the cable at the rear extension housing in the transfercase. The screw thread drops away and there is a small keyed rod that drives from the tcase and spins the cable.

I pulled mine out the other day because the speedo was starting to bounce. Usually caused by the cable gripping and then letting go etc etc which causes a bouce at the needle.

Cleaned out the casing of the cable, regreased (lightly) the cable and re-inserted back in...good as new!

I doubt very much yours is not cable and if the cable is ok, then the drive off the output shaft must be wornout.

Matt.

[niallinireland]

Oh so the cable is just within the speedo, i figured that cos the dash was all electrical.........

Cheers MattMu!!!!, i'll try that

[Garth]

Hi Niall, I would say yours shoud be electric speedo being a 93. easy way to check is to look at the unit on the side of your gearbox, near the output and see if it is a small round sensor with a wire and plug on it. if this is the case then I assume it is faulty and a new one can be fitted easily.
If is is indeed a cable type then what Matt suggested is correct. cheers

[niallinireland]

Just to finish off this thread (unless somebody else got some pearls of wisedom of course)
Got a replacement, its a cable device, nylon gear connnected to a steel shaft with a hole on the other end with keyway. A black plastic encapsulated pulse generator with shaft and key screws on the housing for the steel shaft and generates a pulse when nylon gear is turned in the gear box. Replaced the black encapsulated pulse generator and problem solved.

cheers all niall