Intermittent Speedometer

[AD77]

My speedometer was working and failing intermittently, often working more when under throttle perhaps (maybe I imagined that). It then stopped working altogether along with the mileage counter.

I replaced the speedometer cable as the cable connecting dial to gearbox sensor had snapped. This has brought the milometer back to life but the speedo has only gone as far as being intermittent again... Any ideas? Is it a dash removal job?

[ukdj]

Sounds like a possible speedo transducer issue?

[phazed]

Mine only starts working at about 30mph, very strange.

Without hijacking, could that be a transducer fault?

[quattrophenia]

Mine was very intermittent after replacing the diff bushes. A single turn on the speedo sender on the diff sorted it. If you have not disturbed the diff at all then maybe the sender unit/speedo is on its way out.

[ukdj]

phazed said:

Mine only starts working at about 30mph, very strange.

Without hijacking, could that be a transducer fault?

Have you checked the gap, from memory I believe it should be 10 Thou or less

[storm grey]

mine has just started to play up doesn't work till about 30 mph to

[phazed]

Funnily enough, mine started playing up after I replaced my diff.

I am sure I left a minimum gap, maybe I should increase it a tad?

[jojackson4]

And another for the 20mph + speedo

[phazed]

It's going up on the lift tomorrow so I will adjust a bigger gap as I am sure that it is minimal.

[AD77]

quattrophenia said:

Mine was very intermittent after replacing the diff bushes. A single turn on the speedo sender on the diff sorted it. If you have not disturbed the diff at all then maybe the sender unit/speedo is on its way out.

If this is the issue how big a job is it to sort? Does the dash need to come out?

[ukdj]

AD77 said:

If this is the issue how big a job is it to sort? Does the dash need to come out?

Speedo Transducer is mounted on the diff and is awkward to get at but not difficult to do, so dash doesn't need to be disturbed

[AD77]

I replaced the transducer at the same time as the cable with the below... So if it's not that what else could it be?!


http://www.racetechdirect.co.uk/m0631-tvr-car-part...

[ukdj]

AD77 said:

I replaced the transducer at the same time as the cable with the below... So if it's not that what else could it be?!


http://www.racetechdirect.co.uk/m0631-tvr-car-part...

assuming the transducer is not faulty, this only leaves :-

1. adjustment of the transducer/gap to trigger wheel
2. cabling from transducer to black box behind the dash [adapts speed signal for the ecu]
3. black box behind the dash/connections to/from this box
4. the speedo unit itself/connections to it