Speedo problems

[CoronaC]

Well my speedo on my corona hasnt been working and i only just had a look at it today (fuckin rain), it seams that the cable is alright, the cog on the end wasnt chewed up at all so i thought id stick my finger in the hole of the gearbox and see if i could feel the other cog, i dont know if it was me but i couldnt feel the other cog anywhere, maybe i wasnt sticking my finger in far enough.

Thing with the speedo, on rare occasians it flicks around a little bit jumping up to 10 to almost 40 then back down to 0 withing 1/2 a second but only seams to be at higher speeds, 80+.

So im wondering if the problem would be in the gearbox or the speedo itself? Can eliminate the cable, i just dont want to spend more money on the wrong part again, so is there anything i can do to test it out to see which one needs to be fixed/replaced?

Cheers
Chris

[Cuzzo]

You could try pulling out the cable assembly altogether and give it a good lube up with something, im thinking water proof grease or oil?

[EldarO]

find a way to spin the cable.

maybe something knocked up with a drill or something?

that way, you can keep the cable at the same (stable) speed, and if it still jumps, then its the speedo, or the cable connection on the speedo side.

also, switching in parts that you know work properly helps too.

Elmo.

[JBs]

I used a battery drill to spin mine. Just make sure you do it in both directions to see if the needle jumps.
Cheers

Edit: Mine jumped to about 40kmh so it's fairly obvious.

[sideshow]

unplug cable from spedo end
leave gbox end attached

now roll or drive car a tiny bit with yr finger on the end of cable where it goes into speedometer

it should spin
if it doesnt then work your way back towards gbox

[rob1]

Sometimes oil works its way up the speedo line and into the speedo. My ke55 did this. It will make the speedo flail around and eventually stop working. A new o ring down at the box end can fix it.

[Robbos_Toyotas]

also, if its intermittent, the cable could be broken somewhere half way up too. My first guess would be its come loose bwehind the dash, as this happened to my MA61 also...same problem.

[CoronaC]

unplug cable from spedo end
leave gbox end attached

now roll or drive car a tiny bit with yr finger on the end of cable where it goes into speedometer

it should spin
if it doesnt then work your way back towards gbox

I just tried that one a short while ago, didnt work so i can rule out the speedo, and im still pretty sure i can rule out the cable also it seamed to work fine when i took it out and tested it and wasnt stiff to turn either. So i guess that leaves me with the gbox end, this is gona be fun, guess im going back to the wreckers on monday to get some more parts.

Thanks for the suggestions

Cheers
Chris

[DeftAnesthetik]

forgive me if i am wrong but aren't speedo's electronically driven? the odometer is what is driven by the cable.

[TA-022]

Depends on the car.

[rob1]

i assume it's an older style corona? my money is on the oil. the speedo if it's like the corolla ones uses a magnet style thing in the speedo and if you get any viscous fluid in it it will do exactly what you have said happened to yours

[JBs]

forgive me if i am wrong but aren't speedo's electronically driven? the odometer is what is driven by the cable.

In most cars the cable does both ie: Speed : Km's done ratio. With the cable attached to the gearbox.

[rob1]

the difference is where it is converted.

on older style vehicles the drive is converted at the speedo and the drive spins up at the end of the cable near the speedo. i have a w series box where there are wires that come straight out of the sender at the box.