22 replies to this topic

[SlamDunc]

Hi Folks,

I'm after some advice please?

I took 'Frodo' for a spin this morning as he has been sat for 10 days whilst I was in hospital. It was only a few miles and he seemed fine, started fine etc. I stopped off at a newsagent to get a copy of Mini World and the little sod refused to start again.

I managed to bump start him and he cut out again shortly after and refused to start. I had power in the interior electrics, stereo, cb lights etc but still he refused to start. My volt gauge was reading about 11.5 volts which i think upset the immobiliser and it wouldn't turn off - hence no attempt to start.

I got a charge from a local garage opposite, reset the key fob for the immobiliser and he started on the button but as soon as the stereo kicked back before i could turn it off, on he instantly splutterd and died.

Having resorted to calling the RAC and jump starting Frodo again we found that the alternator was putting out 14.4 volts but the battery was only at 12.25volts.

Is this likely to be the alternator on its way out or do I have some sort of electrical fault that I didn't know about and if so does anyone have any suggestions? I've only had Frodo about 2 months or so and having been hospitalised am still getting to now him!

Any help would ge gratefully received!

[lrostoke]

you don't say what year,but if alternator is putting out over 14v then problem is that voltage isn't getting to the battery.

 

You really need to check along the route it takes.

 

check the voltage at the starter motor battery terminal...if over 14v there, then you are losing it somewhere along the main battery feed cable

 

also check earth connections at the battery

[KernowCooper]

Have a read of the article here http://www.theminifo...ng-basic-tests/

 

  which will help you identify the problem, you will need a voltmeter though

[SlamDunc]

Sorry, should of said. He is a 1995 spi cooper. I think that the RAC chap took a reading off the positive starter motor terminal and it was reading 12.25v. I'll work my way through that link and see what I come up with. I have a horrible feeling I may be calling an auto electrician!

[lrostoke]

If that's the case try tightening the earth cables and also tighten the connection for the battery cable on the starter.

 

If theres over 14v at the alternator and only 12.25v at the starter more than likely a bad connection, its not a very long run from alternator to starter and that's where the cable goes from the alternator to the starter motor

 

Is it the bolt on fixing for the cable at the alternator or the 3 pin plug type.

 

If the bolt make sure tight connection, if the plug pop the back off sometimes they corrode and make a bad connection

Edited by lrostoke, 18 June 2013 - 05:21 PM.

[Captain Mainwaring]

There isn't really much to go wrong !! You've got a battery live to the starter then a cable straight off to the alternator - only one connection apart from the earths.....

Check that the battery to shell earth is good, the engine earth strap is good (if necessary use a jump lead to make a temporary one) and that the alternator is picking up a good ground off it's bracket (almost 100% not that) - after that, you've only got a couple of possible loose connection possibilities.

 

My money is on a duff battery that's gone soft while you left it standing.

[lrostoke]

I'm not so sure about it being battery...If over 14v at alternator and just over 12v at starter motor thats only a run of what 18" of cable shouldn't drop that much

[Captain Mainwaring]

I'm not so sure about it being battery...If over 14v at alternator and just over 12v at starter motor thats only a run of what 18" of cable shouldn't drop that much

 

 

Agreed, which is why I thought he must be talking about running and stopped conditions - 1.75Volts drop will be causing a bit of heat somewhere under charging conditions - I suppose it's possible that funny fused link thing failed - I think SPi's all have them built in as part of the cable from the alternator to the starter lug.

[lrostoke]

Think you could have hit nail on head there Captain, a blown fused link would certainly explain the conditions he's getting

 

Basically battery voltage at starter lug and alternator voltage at alternator

[Captain Mainwaring]

It's an easy check for the OP - if he has a meter, disconnect the plastic plug at the alternator and check for volts between the big spade connector and a good earth on the engine - take care doing this and make sure you select DC volts....not amps or resistance or you'll let the smoke out. 

You should see the same voltage at the big spade connectors as you do at the starter lug (i'm sure on the SPi's that the two big lucar's are commoned up.

 

Obviously do this without the engine running. Alternatively you can use a 12V test lamp if a meter isn't available.

[SlamDunc]

Thanks for the advice chaps. Due to commitments with my little one and general family life I've only just had the chance for another tinkle with him. I've taken the precaution of fitting a new 70amp alternator as the old one was looking very tatty and wanted to eliminate an iffy unit front the equation.

I've also fitted an additional engine earth strap to the front cross member from the engine steady to rule out a poor earth.

With a fully charged battery the volt meter showed 13.2v before starting which dropped to 12.35v with the engine running.

I checked the volts at the starter motor and found they matched the battery at 12.35 volts. the alternator was happily pumping out 14.2 volts but it clearly isn't getting to the battery? This was confirmed by switching on the headlamps and watching the voltmeter in the car dropping sharply!

I even set the throttle at 3000 rpm to check if that increased the volts but it didn't.

Were would I find a blown fused link and what does it look like? I've owned carbed minis previously without this kind of issue so I'm on unfamiliar ground!

Thanks for the help

[lrostoke]

The wire from the alternator goes to the starter motor solenoid, so just follow the brown wires

[Captain Mainwaring]

Thanks for the advice chaps. Due to commitments with my little one and general family life I've only just had the chance for another tinkle with him. I've taken the precaution of fitting a new 70amp alternator as the old one was looking very tatty and wanted to eliminate an iffy unit front the equation.

I've also fitted an additional engine earth strap to the front cross member from the engine steady to rule out a poor earth.

With a fully charged battery the volt meter showed 13.2v before starting which dropped to 12.35v with the engine running.

I checked the volts at the starter motor and found they matched the battery at 12.35 volts. the alternator was happily pumping out 14.2 volts but it clearly isn't getting to the battery? This was confirmed by switching on the headlamps and watching the voltmeter in the car dropping sharply!

I even set the throttle at 3000 rpm to check if that increased the volts but it didn't.

Were would I find a blown fused link and what does it look like? I've owned carbed minis previously without this kind of issue so I'm on unfamiliar ground!

Thanks for the help

 

 

With respect....it's all in the previous posts...I'll guess that your fusible link has gone west.

 

If you carry on....you'll wreck your new alternator and maybe fry something else in the process - whatever you do, do NOT disconnect the IND wire with it in this condition, it;s the only thing at the moment regulating the alternator.

It was pointless you changing the alternator if you didn't following the advice given and make sure it was actually connected to something in the first place...

Edited by Captain Mainwaring, 27 June 2013 - 11:48 AM.

[Captain Mainwaring]

Fused link is between the starter time and the alternator plug - it's in heat resistant sleeving. 

Use your multimeter- you'll find it.

[zony]

The later minis have a very weak spot with all the main power connectors joining together at one point. This is on the solenoid just behind the grille. take the grille off, clean all these cables, about 4 of them use a bit of copper grease and re tighten. Its a bad design.

 

It takes a lot to blow the fusible link, if it has gone there may well be evidence of burnt wires in that location. It is a fatter bit of wire about 100mm long built into the loom, usually with a black rubberised waterproof sleeve over it.

Edited by zony, 27 June 2013 - 11:55 AM.