V8S and 290S speedometer

[rupertrr]

Good afternoon.

I have a 1992 V8S and the speedometer has packed in. Neither the speed nor the distance are working.

I have enquired about getting it mended but was told that parts are no longer available and it will not be possible to sort it out.

Can anyone here please advise if the speedometer from a S3 290 will work in the V8S. Obviously the gearboxes of the two cars are totally different but the speedometers look the same and the wiring plug into the back of the unit etc appear identical. I am thinking that maybe the pulse from the gearbox sender thingies will be different, so that even if it works in the V8S the indicated speed will be totally wrong.

Can anyone help, please?

As an alternative, has anyone tried using a GPS speedometer in their car. It would be totally independent of the gearbox sender and might be an alternative worth trying if I can't get my original one sorted.

Many thanks to you.

[rupertrr]

Hello - OP here again.

Many thanks for all the helpful suggestions that everyone has made.

The speedometer that I have fitted was originally recording speed perfectly well but the odometer bit wasn't working. It was stuck on ----99.9 miles I tried tapping it as I drove along, as suggested in other threads, but it didn't make the odometer work so I took the speedometer out and had a look inside - then decided it was beyond my abilities to fiddle with it so I contacted Cluster Repairs in Waltham Abbey (who are not that far away from me) and they advised a lack of spare parts to repair the odometer. They were very helpful (I have used them before to replace the failing LED readout on my early Range Rover L322. They did a perfect job of it and their repair has lasted much longer than the original that Land Rover/BMW did) so I tried them for my TVR speedometer but to no avail.

I put the speedometer back in the car deciding that I could live without knowing the mileage as long as I knew the speed only to find the speedometer side of things didn't work either. I assume I messed something up when I had a look inside.

I was experiencing the engine cutting out when I came to a halt although it would start again immediately but I have fitted a new ignition amplifier and a new coolant temperature sender (the ECU one rather than the temperature gauge one) and that problem has now been resolved I am pleased to say.

I think my course of action for now will be to take it out again and recheck the connections and earth. If that doesn't work I will have a look underneath to see if the speed sender cable is OK. I may be able to borrow a speedometer out of a 290S (which is what prompted my original question) so may try that as a last resort just to eliminate everything else. Failing all that it sounds like a call to Speedy Cables and apparently a long wait, or more likely to Ryan Linley Restorations, although I am still considering the GPS idea.

Thank you everyone. An excellent example of Pistonheads at its best.

Edited to add a bit more waffle.

Edited by rupertrr on Sunday 17th March 09:03

Edited by rupertrr on Sunday 17th March 09:37

[rupertrr]

Thank you to V8s4me and Mentall for the latest posts.

I've got the dash board and instruments out this afternoon and checked the wiring at the speedo end and all appears OK. I'm going to get the car up on ramps during the week and have a look at the wiring down below. I'll keep the dash off until I've checked everything.

Wish me luck.

Thank you again, everyone.

[rupertrr]

Thank you, Fefeu52 - that's a cracking idea. I'll give it a go once I've traced back to it.

[rupertrr]

Hello - OP here again.

Thank you to hillclimbmanic (above post) - yes it is the LT77 gearbox. Good info on the different senders. Thank you.

So far I have been underneath my car and found the sender unit in the gearbox. I have traced the wiring from it and that all seems fine. There is no point at which it has been trapped of chafed on anything that I can see, even with an inspection mirror and one of those little camera things that you can poke down holes to look inside engines. Without taking the exhaust off I can't reach the sender unit to remove it and I haven't had time to do so yet.

However - I have got hold of a speedo from a 290S and tried it on my car. It works, showing speed and the miles are clocking over. Unfortunately though it is wildly inaccurate, the speed reads a lot higher than reality (checked against my sat-nav) and the miles are clocking up at about twice the true distance. I am assuming from this that the sender is sending a signal and that it is the different gearing of the V8S and 290S that is making the difference. I am more than happy to be corrected on this.

I have emailed Ryan Linley about my V8S speedo and getting it looked at but have not heard back from him yet. In the meantime I am leaving the 290S speedo in my car - to fill the hole up in the dashboard as much as anything - and have ordered a cheap GPS speedo to use until I can get the original speedo fixed.

Thank you again, everyone.