really fed up

[240]

as some may knwo my speedo has packed up, have had it to the auto lec who rewired the sensor which didnt work, then i tried 4 different instrument panels and still it didnt work, today i have spent hours getting the old sensor out and replacing it with another hoping this was the cause but still nothing, i am fed up with the damn thing now.

speaking to braydon they say its the instrument panel or sensor but speaking to my local volvo indie guy he says its the drum in the diff but to have it checked the diff has to come off etc etc and thats a bill for £150 upwards but braydon say that they have never heard of one go in 30 years.

i know that one of the instrument panels works fine as it came tested from mike.

we connected a meter to the speedo wires and when driving the meter reading rises so the wires are ok, when reconeecting the instrument panel the needle just flicks up and down a couple of millimetres so it must be getting some sort of power/signal

so do i spend the money with the volvo indie who wants to take the diff off on the off chance or do i listen to braydon and buy a brand new sensor for around £130?

right now im sick of throwing money at it with experts and its still not working

im not driving around using a sat nav all the time or as somebody else sugessted using the other traffic as a gauge!!!

if i dont get it sorted then its going which would be a shame as its had just over £1000 spent on it and everything has been done, seals clutch brakes etc.........

thanks

does anybody have any ideas as to what it could be?

[Clan]

They dont need to take the differential apart! they are just guessing .. the signal needs to be properly diagnosed with an oscilloscope at the terminal on the speedo that will tell you ( or him!) whether it is a speedo or a sender/wiring problem ... Its a very simple system , any electricaly minded person could fathom it out ..

[Paul240480]

I seem to recall reading an article in the old 'technical' . IIRC the earth for the dash is behind the clock. Follow the earth wire from the clock & you should find it. Check there for breaks & cleanliness. A bit of muck there can cause a variety of faults, one of which is a duff speedo or erratic speedo. I think the 'fix' was to take the wires to another point to make the earth. Was it a Paul Clifton article? Thought it worth mentioning

Anyone else recall it or am I from another planet? No need to answer that lol.

[Clan]

yes i recall it too , there is a black wire going to a big 3 pin plug on the tacho , if you connect a black wire to this and connect to the body somewhere it cured the Tachometer not working , maybe it will help the speedo too .

[240]

everything else on the panel works apart from the speedo, would it still be worth checking the earth?

as far as i know the auto lec has tested the system and he says it is getting continuity to the instrument panel is that what you mean?

thanks

[240]

Originally Posted by Clan

yes i recall it too , there is a black wire going to a big 3 pin plug on the tacho , if you connect a black wire to this and connect to the body somewhere it cured the Tachometer not working , maybe it will help the speedo too .

worth a go!!! ill try it tomorrow when its lighter

[Clifford Pope]

Try swapping the 2 wires over from the sender. I swapped a working sender from a 93 into a 92 and it didn't work. Close inspection showed the wire colours were reversed between the two years.
Or perhaps as a trial first, see if the speedo reads when you go backwards.

[240]

hi clifford

i saw your thread and have tried that but no joy, i didnt have as much trouble getting the sensor out as you did the only trouble i had was removing the outer metal ring!! but thanks anyway for the tip

[Clan]

Originally Posted by 240

everything else on the panel works apart from the speedo, would it still be worth checking the earth?

as far as i know the auto lec has tested the system and he says it is getting continuity to the instrument panel is that what you mean?

thanks

well there are only 3 wires , a 12v feed , an earth and a pulsed signal which is best viewed with an oscilloscope .. if all 3 are there , then you have to assume the speedo itself is faulty .. unless it is the sugnal weak or not there ..

are there shims under the sender to bring it closer to the toothed wheel in the axle ? What model year is yours? some have shims to adjust the working gap . there are about 6 shims of different thickness listed for a 1991 model .

[240]

when we removed the old sensor it had one shim on which we put onto the replacement sensor,

we tested the wires using this method......my sensor is the same as the one in the photo

http://vol240.blogspot.com/2007_04_01_archive.html

the link says if the meter rises then the instrument panel is at fault however the panel i got from mike was tested and worked fine before sending it to me and we have tried 4 different units none worked.

we don't know how the auto lec tested it but i have since found that he has replaced around 8 inches of wires from the loom to the sensor but this hasn't had any effect.

one thing we tried was to plug the replacement sensor into the loom and used a piece of metal and moved it quite fast past the sensor and the needle just flicked much the same as its still doing now its been fitted.