30 replies to this topic

[minisilverbullet]

Battery is one year old, though has be discharged a couple of times over the winter, when the car wasn't used. 

 

Fan belt tight and not slipping. 

 

On start up the battery light doesn't light up, should it (I cant remember)?

 

The car is wired for daylight running lights, these do not come on at start up, unless the engine is revved. 

 

Ideas?

[Alex_B]

The charging light should come on with ignition and go out when engine is running, check the voltage at the battery when the engine is running i think it needs to be above 13.8v to charge the battery and should be about 14.5v that should highlight if it's a battery or charging issue

[sonikk4]

Check the bulb first to see if that is the issue, then check the output of the alternator, me i do this at the alternator. Could be something as simple as loose plug on the back of the instrument cluster.

[KernowCooper]

Here is the write up about ignition warning lights http://www.theminifo...g-how-it-works/

And checking the charging system http://www.theminifo...ng-basic-tests/

 

Both of those if followed correctly should pin point the problem

[minisilverbullet]

Thanks for the advice guys. 

 

Kernowcooper I followed you guide on the charging system. 

 

Battery on full charge and the indicator (on the battery) light says it is healthy

 

Results where 12.8v at each of the big pins on the alternator. 0.3v on the small pin when ignition on or engine running.  Still now ignition light on the dash. I tried the trick of a wire on the the small pin and then to an earth and still no ignition light. 

 

Also when the car is off i get around 12.8v across the battery, when the car is running and when the revs are increased i still get around 12.8v

 

I guess this points to a bad alternator.....

[KernowCooper]

Read No6 again on the alternator test

 

with the 6.3mm lucar in the small plug and the ignition on and touch the end of the lead in the small plug to a good earth point the LIGHT SHOULD COME ON If it does not come on then the wire is broken or the bulb is gone, Bulb blown no exciter voltage to start the alternator charging.

 

Check the bulb first, then check with a multimeter the wiring.between bulb and alternator

[minisilverbullet]

Read No6 again on the alternator test

 

with the 6.3mm lucar in the small plug and the ignition on and touch the end of the lead in the small plug to a good earth point the LIGHT SHOULD COME ON If it does not come on then the wire is broken or the bulb is gone, Bulb blown no exciter voltage to start the alternator charging.

 

Check the bulb first, then check with a multimeter the wiring.between bulb and alternator

Aha i see! 

 

I just assumed that since there was no voltage it was the alternator at fault. 

 

I check the bulb/wiring  and report back 

 

Thanks Again

[minisilverbullet]

So bulb works fine (would have been great if it were that). 

 

As for checking the wiring I am getting my self a bit lost. 

 

So running from the small pin on the alternator is a bout a 5cm length of wire (brown and yellow), this then connects to a green connector whih has a thicker black wire running out of it. Chasing this wire down it is joined by a red wire which runs to the starter ( i think) both wires run together to a black box (some sort of relay). The wires appear to be un damaged. 

 

Could the issue be the "black box"? 

 

Inside the car, behind the dash, I think the ignition warning lamp wiring is the same brown and yellow as that which runs form the alternator. This too seems fine, though I am not really sure how I would test it. 

 

The car is an SPI

 

I think the problem with the ignition light may have started after i tightened the fan belt, I allowed my spanner to somehow spark on the connectors of the alternator. 

 

I should say that the car runs and starts as normal. 

 

Many thanks again!

[spaulwill]

I am not familiar with SPi however if you look at a carb model like 1000cc wiring diagram, there are 3 wires off the alternator,

 

Brown - Directly to solenoid

Brown/Blue - Directly to solenoid

Brown / Yellow - directly to ignition light.

 

So you could try the following if you do not have a alternator tester. A simple test lamp applied to all above should give an output except B/Y which will obviously go out. You just need to check is the alternator producing voltage, does sound from your sparking accident that perhaps the rectifier has been damaged. This wil need to go to a specialist for repair. But check the basics first

[minisilverbullet]

I am not familiar with SPi however if you look at a carb model like 1000cc wiring diagram, there are 3 wires off the alternator,

 

Brown - Directly to solenoid

Brown/Blue - Directly to solenoid

Brown / Yellow - directly to ignition light.

 

So you could try the following if you do not have a alternator tester. A simple test lamp applied to all above should give an output except B/Y which will obviously go out. You just need to check is the alternator producing voltage, does sound from your sparking accident that perhaps the rectifier has been damaged. This wil need to go to a specialist for repair. But check the basics first

Yes I have battery voltage from both the larger tow connectors, nothing form the smaller. 

[KernowCooper]

Then there is a break in the wiring from the bulb to the alternator somewhere.

[minisilverbullet]

Ok, which wire should i chase after the wire from the alternator goes into the "black box" I refer to in the post above. 

[minisilverbullet]

Can anyone tell me the name of the "black box" i am referring too.......

 

Its tough to search for it when i dont know what it is called 

[KernowCooper]

Where is the blackbox? size location ?

[bmcecosse]

At 12.8 volts with engine running at decent revs - it's not charging.   Possibly needs brushes in the alternator.  Don't know about 'black boxes' - I suspect someone has been messing with the wiring......rather confirmed by your 'running lights' comment.  Your shorting out with a spanner may have damaged the diodes in the alternator - although really it shouldn't !   You should NEVER let a battery run down - either fit a solar charger to keep it up over winter - or top-up charge it every few weeks.