speedo working then not working?

[marcus1970]

Hello all,

My speedo has been playing up recently and then today it just stopped working. No indication of speed at all and the mileage froze and the trip meter isn't moving either. Then I gave it some beans and it sprang back into life - but only for a short while.

It's basically been like this the rest of the day - working, not working, sticking st 30 then flipping up to 50 and then back to nothing.

I'm suspicious of my alternator for other reasons recently, could it be attributed to this?

MB

[touching cloth]

Hows your rev counter? Obvious check would be big fuse but (IME) rev counters goes bonkers first if it's the fuse, worth checking/replacing anyway just to rule out (that's if you haven't already).

[marcus1970]

touching cloth said:

Hows your rev counter? Obvious check would be big fuse but (IME) rev counters goes bonkers first if it's the fuse, worth checking/replacing anyway just to rule out (that's if you haven't already).

Rev counter is fine, but it doesn't work at idle until the car has warmed up a bit?

MB

[Gaffer]

Speedo transducer. Thats whats happened to both my Chim and Sag.

You can get a new one from TVR Power. Not sure how hard they are to fit though, but they are underneath the car at the back on the diff.

Claire

[RUSSELLM]

Both of the above

One for the rev counter, one for the speedo.

[Mad Mark]

The speed transducer is easy enough to fit.
Clever Trevor have the for £67.69

[DonnyMac]

Sure you’re not falling asleep at the wheel and only opening your eyes at 30, 50 and stationary?

Seriously though, I’ve not had the speedo issue but did have the rev counter not showing until the car was warmed up and sometimes erratic on lift off, no transducer change, got it back from an APM service (where I think he changed the big fuse) – all speedo issues fixed.

[grass widow]

We had a speedo that didn't work, turned out to be the ribbon. New ribbon everythings fine.

When the speedo doesn't work you have to look out for the drivers door opening whilst on the move, as the car thinks your stationary so doesn't lock it shut. Its a tad unnerving trying to drive and close the door at the same time

[marcus1970]

Mad Mark said:

The speed transducer is easy enough to fit.
Clever Trevor have the for £67.69

Where abouts is it on the car?

Cheers

MB

[Buffoon]

marcus1970 said:

Mad Mark said:

The speed transducer is easy enough to fit.
Clever Trevor have the for £67.69

Where abouts is it on the car?

Cheers

MB

On the Dif.

Needs to be properly gapped. Test it while jacked up and wheels off the ground if you can do it safely.

[marcus1970]

Buffoon said:

marcus1970 said:

Mad Mark said:

The speed transducer is easy enough to fit.
Clever Trevor have the for £67.69

Where abouts is it on the car?

Cheers

MB

On the Dif.

Needs to be properly gapped. Test it while jacked up and wheels off the ground if you can do it safely.

When you say properly gapped, is there a measurement?

Cheers

MB

[Mad Mark]

I would say as close as poss but with a gap!! sure its only some sort of magnetic switch.
I could be totally wrong though!!!

[HarryW]

Mad Mark said:

I would say as close as poss but with a gap!! sure its only some sort of magnetic switch.
I could be totally wrong though!!!

I'm sure 1mm rings a bell, so make that 0.1mm -0+1mm to be sure

[Gaffer]

Hold a sheet of A4 paper betwen the two - thats the gap ie tiny

Claire

[marcus1970]

Im lying under the diff with my head nearest the rear of the car - where the blazing squad is the transducer.

I can see lots of muck and chasssis and diff, what am I looking for?

Cheers

MB

[Brummmie]

Look for a toothed ring on the drive shaft next to the diff, you will see a bracket holding the sensor. You wont see it unless you get right underneath the diff housing.

[central]

Dunno if these help ?




From when mine gave up about a year ago.

[marcus1970]

Thanks guys.

I take it the sensor is detecing the movement of the toothed cog/ring on the driveshaft?

MB

[marcus1970]

Gaffer said:

Hold a sheet of A4 paper betwen the two - thats the gap ie tiny

Claire

Found the transducer and all looks ok, but one thing...

When you put the new one in how do you know if it's too close or not close enough - is there a thread stop or something that it butts up to?

[central]

marcus1970 said:

Gaffer said:

Hold a sheet of A4 paper betwen the two - thats the gap ie tiny

Claire

Found the transducer and all looks ok, but one thing...

When you put the new one in how do you know if it's too close or not close enough - is there a thread stop or something that it butts up to?

Feeler gauge. Can't remember what the gap is though...