New S3C owner

[party7]

After much deliberation I have finally taken the plunge and I am now the lucky?? owner of a storm grey S3c.
Mechanically fairly well sorted but requires some cosmetic TLC and a growing list of niggles sorting.
I have found posts on the forum to a few of the issues i.e. slow electric windows, erratic fuel gauge etc., but I wonder if anybody can help with the following:-
I have noticed that my speedo seems to be over reading by about 20 mph i.e. actual road speed = 50 mph, speedo reads 70 mph. Whats the most likely culprit a faulty sender or a duff speedo?

[wizzer]

Hi welcome to the trials and tribulations of TVR ownership, Oh I forgot the huge amount of fun. As for the erratic speedo that I afraid is pretty much par for the course. Some owners have uprated it, but not cheap. Just except its a tiv and enjoy. This is a great forum with a huge amount of help any problems you have will have been encounter before and somebody will have a fix. Enjoy!

[mycroft]

I know its not sorting the problem but if you have a smart phone just use a speedo app with a screen mount , they are very good .
Dale

[party7]

Thanks for the answers guys, much appreciated.
I really can't believe that it’s normal for the speedo to be 20 mph out.
I'm considering trailing some rope with knots in it behind me, seemed to work OK on ships and probably just as accurate!

[S2Andy]

Strange, mine is absolutely accurate when compared to Tom Tom. Have the tyres been changed to a different profile from 205/60/15, or perhaps the diff ratio has been changed?

[techbotics]

hmm strange mine only does this with the lights on its ok the rest of the time.. Lols and welcome..

Damian S3

[phillpot]

party7 said:

I really can't believe that it’s normal for the speedo to be 20 mph out.

Other gauges are a bit hit 'n miss but speedo should be fairly accurate. Mine reads about 4mph high at 70 (compared to sat nav) don't know what but somethings wrong

[tvrgit]

techbotics said:

hmm strange mine only does this with the lights on its ok the rest of the time.. Lols and welcome..

Damian S3

I have had mine for 9 years and it's exactly like that! OK until you put the lights on, then vround 20mph too high.

I can't remember now whether I've fixed it or not... I just got used to it.

[techbotics]

tvrgit said:

techbotics said:

hmm strange mine only does this with the lights on its ok the rest of the time.. Lols and welcome..

Damian S3

I have had mine for 9 years and it's exactly like that! OK until you put the lights on, then vround 20mph too high.

I can't remember now whether I've fixed it or not... I just got used to it.

crazy I knew I wasn't alone.. Got to be earth related surly? If you do realise its fixed and remember how please let me know.. I am too scared to dismantle the dash..

cheers

Damian S3

[Bobhon]

I had the same issue with my old S2 and fixed it by changing the speedo sensor drive gear in the gearbox. It was the small gear which just lifts out of the gearbox, not the one on the main drive shaft.

On mine the gearbox had been changed for a recon one and they hadn't moved the speedo drive gear over to the new gearbox. Has yours had a recon box fitted?

The bad news is that you can't buy the correct drive gear as it appears to have been a special ratio for TVR. I had to buy a cable type speedo drive gear from my local Ford dealer and get it machined out and a new drive insert made up.

I guess that you've really got to want to fix this one.

End result was a totally accurate speedo within 1 mph of a GPS speedo.

I thought that I put up a post about it but I can't find it in the search.

Bob

[glenrobbo]

I haven't the faintest idea whether my S1's speedo is accurate or not
because beyond 35mph the gauge is hidden by the steering wheel.
It sounds fast though!

[party7]

Wow I'm impressed by all the responses its good to know that there's such a helpful bunch of folks out there.
Looks like a bit of detective work is required - wheels are std dia and fitted with 206/60/15 but I can't vouch for the gearbox not having been changed before I got the car.
Sounds like the sensor is the starting point.