19 replies to this topic

[purple_fly06]

Hi tmf, I'm hoping that someone can give me some sound advice.

 

This all goes back to around 2 months ago when i was driving my mini (1275 GT) and all of the sudden it completely died, not even the hazards worked. 

 

Since that i have been quite busy and i managed to get around to looking at it today, I have:

- Charged the battery

- Checked the fuse box connections

- Checked the fuses

- Checked the starter solenoid connections

- Checked the earth in the boot and in the engine bay

 

I put the keys in and turned the ignition on only for the ignition light to have the faintest of glows and then die around 1 second later. I tried a second time and this time nothing happened. Even with the ignition on none of the electrical items work, the hazards, flasher, horn etc... all dead.

 

As a last resort i used an insulated screwdriver to bridge the terminals on the starter motor. There was the tiniest spark (in the past when i have done this its pretty obvious if it has power there or not) it was so small that i could hardly make it out.

 

My question is what is the most likely reason for this sudden fault, faulty battery? Starter solenoid? any other reasons?

 

Cheers,

Josh

[cal844]

Try a known good battery first, sounds to me like there could be a faulty connection at the starter.

[cal844]

Try a known good battery first, sounds to me like there could be a faulty connection at the starter.

[WillCarter]

Swap the battery and then check if the alternator has died

[ukcooper]

have you checked the main power cable round the subframe , boot for breaks ??

[Thelowrider]

Check voltage at the battery terminals? Then move to the front of the vehicle and measure the voltage at different points for example the fuse box (permanent feed wise), starter solenoid, @ the starter itself (depending on if you have pre engaged or inertia) make sure they correspond to the reading on the battery. If the light is only coming up dimly it points towards a wiring issue always check your earth connections aswell they quite easily get overlooked when looking for wiring problems.

Another thing to check is measure voltage of the ignition off and check it when you flick ignition on if it drops dramatically the battery is goosed.

[Sask_Mini]

I think everyone else is on the right track.  To rule out a bad ground or bad battery cable you could take the battery and some booster cables (jumper leads), take the battery to the front of the car, hook the negative terminal to the ground in the engine bay and then jump the positive terminal to the positive terminal on the starter solenoid.  Try starting the car and see what happens.   

[purple_fly06]

Thanks for the ideas guys!

 

Try a known good battery first, sounds to me like there could be a faulty connection at the starter.

 

Tried a good battery at first, still completely dead.

 

Swap the battery and then check if the alternator has died

 

Swapped the battery but I'm unsure how to check if the alternator has died?

 

have you checked the main power cable round the subframe , boot for breaks ??

 

I can visually inspect it that easily as it is currently in a stable and i don't have access to a ramp at the moment. But i first suspected this may have been at fault.

 

Check voltage at the battery terminals? Then move to the front of the vehicle and measure the voltage at different points for example the fuse box (permanent feed wise), starter solenoid, @ the starter itself (depending on if you have pre engaged or inertia) make sure they correspond to the reading on the battery. If the light is only coming up dimly it points towards a wiring issue always check your earth connections aswell they quite easily get overlooked when looking for wiring problems.

Another thing to check is measure voltage of the ignition off and check it when you flick ignition on if it drops dramatically the battery is goosed.

 

I used the multi-meter and have checked various points on the vehicle as you suggested. The battery was reading 12v and when i checked the main power cable to the solenoid it was flickering between 4-6v which suggests to me that this cable may be damaged or has degraded?

 

I think everyone else is on the right track.  To rule out a bad ground or bad battery cable you could take the battery and some booster cables (jumper leads), take the battery to the front of the car, hook the negative terminal to the ground in the engine bay and then jump the positive terminal to the positive terminal on the starter solenoid.  Try starting the car and see what happens.   

 

After seeing the reading on the multi-meter above i then tried this method (essentially bypassing the main power cable to the solenoid...) unfortunately this did nothing either so i am no even more stumped?

 

Am I missing something really obvious, if it helps the diagnosis the hours leading up to this it was running extremely lumpy and misfiring. i had the intention of looking at it when i got back home but i didn't make it 

[WillCarter]

If you've swapped the battery and this new one also dies, it's likely that the alternator isn't working.

 

Try this: http://www.todayifou...car-alternator/

[purple_fly06]

Okay cool, i cant test the alternator by the looks as step 3 requires me to start the engine but ill take your word for it.

 

Is it possible for the car to cut out completely if the alternator stops working whilst the engine is running? I'd have thought it would have continued to run until the ignition was turned back off, then it wouldn't have started... or could it be that once there is a break in the circuit it looses electrical power?

[WillCarter]

Okay cool, i cant test the alternator by the looks as step 3 requires me to start the engine but ill take your word for it.

 

Is it possible for the car to cut out completely if the alternator stops working whilst the engine is running? I'd have thought it would have continued to run until the ignition was turned back off, then it wouldn't have started... or could it be that once there is a break in the circuit it looses electrical power?

The alternator won't affect the engine, except for when the battery is dead and won't start the engine. Only the electrics will be affected by the alternator not working. But it will mean that it isn't charging the battery and therefore none of the electrics will work once the battery has died. 

 

If your battery is fully charged, even if the alternator isn't working, the electrics should all still work until the battery is dead, meaning that the fault may be the main wires from the battery 

Edited by WillCarter, 03 June 2018 - 12:10 PM.

[purple_fly06]

Okay, i have tried two batteries on it now and still no power so that would make it less likely that the alternator is at fault?

It has a pre engaged starter motor, is there anything that may have gone wrong with that? It was replaced around 8 months ago.

[WillCarter]

Okay, i have tried two batteries on it now and still no power so that would make it less likely that the alternator is at fault?

It has a pre engaged starter motor, is there anything that may have gone wrong with that? It was replaced around 8 months ago.

Have the batteries both been fully charged and the electrics still haven't worked? If they're fully charged then the alternator won't be the problem. 

 

I don't think that the starter motor would have anything to do with the other electrics whilst the ignition is on. However, if there's a problem starting the car then you can work backwards from the starter motor. 

 

I'm afraid I don't know much about starter motors but have a look at this: http://www.theminifo...t-not-cranking/

[purple_fly06]

Both batteries are fully charged, im tempted to get it on a ramp and replace the main power cable to the front of the car (and the started solenoid for the sake of £6).

Im not electrically minded at all but if I’m getting 12v at the battery and then where the power cable goes to the starter solenoid im only getting 6v-ish i dont think thats enough power to power any of the electrical items... im hoping thats the case anyway. That may also explain why i had the faint glow on the ignition light only for it to go out.

[WillCarter]

Both batteries are fully charged, im tempted to get it on a ramp and replace the main power cable to the front of the car (and the started solenoid for the sake of £6).

Im not electrically minded at all but if I’m getting 12v at the battery and then where the power cable goes to the starter solenoid im only getting 6v-ish i dont think thats enough power to power any of the electrical items... im hoping thats the case anyway. That may also explain why i had the faint glow on the ignition light only for it to go out.

 

I'd imagine it's the power cable then, there's no way that you should be losing 6v between the battery and the starter. Replacing both would likely see it fixed. 

Edited by WillCarter, 03 June 2018 - 12:45 PM.