electrical issues

[smckeown]

My car has had starting issues for a while, and only starts recently when being jump started. Having ruled out a flat battery, I assume the other cause can be poor earthing.

I've been plumbing in a new dash and now it doesn't even turn over and makes wierd buzzing noises when you put the ignition switch on.

Another sympton is when I turn the fia switch on my indicatiors work fine and get 12v to the dash. When I turn the ignition switch on it only gets around 6v. Would this also indicate an earthing problem or something different ?

[Steve_D]

I think you've screwed something bigtime.
Any chance of going back to the wiring you had before and start again.

Other than that we have little or no chance helping you without knowing the circuits involved and what you have changed.

Steve

[smckeown]

I havent actually disconnected many wires. I'd say just one isnt connected as before..I can pop that back on easily enough. I've just wired in new indicator slights so far so nothing serious.

I've done more etsting and here's a better explanation of the situation.

FIA switch on
ignition switch off
indicators dash light work normally, receiving ~8 volts

when I switch the ignition switch on, then
indicator dash lights receive ~5 volts, then over a few seconds the voltage goes down to 0

[GreenV8S]

smckeown said:

indicators dash light work normally, receiving ~8 volts

when I switch the ignition switch on, then
indicator dash lights receive ~5 volts, then over a few seconds the voltage goes down to 0

If your battery is OK then you should get 12V or nothing. So confirm the battery voltage is OK and then trace forwards to find where your voltage is being lost. Poor earths would be an obvious candidate. It's worth being careful because in some situations if the main engine earth fails it can end up trying to earth the starter current via the engine loom, throttle cable etc which can do a lot of damage.

[smckeown]

thanks for that.

I tested my wife's car battery and it game 12.6 volts. Then tried my race battery and it was 10.2 volts. And i recently charged it up.

I also tried jump leads from the wife's car to mine and it still game the same symptoms as I was getting originally

[GreenV8S]

smckeown said:

tried my race battery and it was 10.2 volts. And i recently charged it up.

If that's nominally a 12V battery then either it's flat, or you've got a duff cell.

[smckeown]

thanks for your help

solved - flat battery....how it went flat so quick i'll never know!

[GreenV8S]

smckeown said:

thanks for your help

solved - flat battery....how it went flat so quick i'll never know!

Some of the gel batteries won't put up with being deep discharged, so if it's anything fancy you might want to ensure that doesn't happen again.