Electrical failure

[Simon-n7710]

I’m hoping some clever soul can work this one out!

1993 model so, as far as I know, doesn’t have the two big fuses.

I was driving along, accelerated to overtake a bicycle. Stutter. Then fine. Stopped at a junction and it stalled. Turned the key - nothing. No dash lights, so fuel pump, not so much as a click from the starter motor

Fast forward - replaced all the fuses and relays.

Connect the battery and the only thing firing up is, what sounds like the central locking or maybe the boot release cycling.

However, still no power to anything else at all.

Battery fully charged.

Earth issue??

[magpies]

Are you competent with a multi-meter?

Do you have a basic wiring diagram of the car?

You need to find where the battery volts get to and where they stop.

[Simon-n7710]

I am not at all competent with electrics…!

However the symptoms seem quite specific and with the weather being so nice it’s itching away at me.

I have an auto electrician coming in a week or so but he’s not a TVR specialist.

Edited by Simon-n7710 on Saturday 16th April 20:26

[Belle427]

Check battery cables and negatives first, the pictures here will help with the awkward one!
https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Simon-n7710]

Belle427 said:

Check battery cables and negatives first, the pictures here will help with the awkward one!
https://www.pistonheads.com/gassing/topic.asp?h=0&...

Good shout. Centre console out I assume?

[Belle427]

I seem to remember it being further forward under the side of the dash.

[Simon-n7710]

Well, turns out the live cable to the starter motor was loose. That caused a total power loss.

Confused the electrician as he’s have expected it to be on a separate circuit, rather than the love going to the starter motor and then back into the car to power *everything else*

So the car is running again, and as well as it ever was.

[Polly Grigora]

Simon-n7710 said:

Well, turns out the live cable to the starter motor was loose. That caused a total power loss.

Confused the electrician as he’s have expected it to be on a separate circuit, rather than the love going to the starter motor and then back into the car to power *everything else*

So the car is running again, and as well as it ever was.

Yes, crazy isn't it

To think that sports cars are built for speed and TVR didn't realise that the heavier the car is the slower it will be

You could get rid of those power cables from starter to fusebox and run a cable from battery to fusebox and go faster

[Belle427]

Usually as standard there shouldn’t be a 2nd cable back from starter to fuse box, that doesn’t make much sense to me.
I’d look into this personally as there should be a fused cable from battery to fusebox.

[David Beer]

Belle427 said:

Usually as standard there shouldn’t be a 2nd cable back from starter to fuse box, that doesn’t make much sense to me.
I’d look into this personally as there should be a fused cable from battery to fusebox.

Quite agree !
Penny/ poly whatever, has no clue.

[Simon-n7710]

It is a bit weird isn’t it. We spent 3 hours trying to work out why there was no power only to find tightening up the live to the starter motor was the problem.

[Polly Grigora]

Simon-n7710 said:

It is a bit weird isn’t it. We spent 3 hours trying to work out why there was no power only to find tightening up the live to the starter motor was the problem.

Certainly is weird, perhaps a decision was still to be made about the location of the battery when the looms were being produced, picking up the supply from the starter is bomb proof but.......

Here are the diagrams that may help with fault finding in the future





Found here - https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Simon-n7710]

Ooh thank you! Very useful indeed.

I’ll be getting it re-wired.

It looks original by the way…

[Polly Grigora]

Simon-n7710 said:

Ooh thank you! Very useful indeed.

I’ll be getting it re-wired.

It looks original by the way…

You're welcome

Rewire, interesting, big job but major improvements can be made

Enjoy

[Belle427]

Many choose to upgrade the battery to starter cable anyway as the old one is borderline size wise and gets a hard life with the engine bay heat.
From the factory as far as I know there should be a feed via an 80 amp fuse from battery to fusebox, but who knows what previous owners might have done.

[Simon-n7710]

I believe, as an early model, there is no 80 nor 100amp fuse?

[rigga]

David Beer said:

Belle427 said:

Usually as standard there shouldn’t be a 2nd cable back from starter to fuse box, that doesn’t make much sense to me.
I’d look into this personally as there should be a fused cable from battery to fusebox.

Quite agree !
Penny/ poly whatever, has no clue.

Maybe his /her next identity will improve.

On the plus side, no relays mentioned as a fix.

[Polly Grigora]

Simon-n7710 said:

I believe, as an early model, there is no 80 nor 100amp fuse?

Any battery supply 80 Amp fuse fitted close to the fusebox achieves nothing and there is no possible reason to be found for including one

[Belle427]

Simon-n7710 said:

I believe, as an early model, there is no 80 nor 100amp fuse?

Quite possibly yes.