17 replies to this topic

[scud]

Hi all

Just got a mini italian job, 10 yrs since last had one so had forgot a couple of their 'foilables'

Anyway wife left the lights on and flattened battery.

Now I am a bit older did the correct thing of removing battery rather than charging in situ, however when reconnecting connected red lead to +ve terminal and black to -ve terminal, only to realise black was actually pos and red was neg!

Anyway car is now dead, tried jumping to check if I had just knacked the battery and can't even jump it- not even ignition lights (although they did come on for a sec when reconnected batt before jumping)

Not done this before so not sure what I have wrecked, coil? ideas? help?

Thanks

[dklawson]

You won't have done any damage to the coil.

Remove the alternator, take it to a shop and ask that they bench test it.

Check any fusible links on your battery cables and check all the fuses in the fuse box. While you're there, inspect all the heavy gauge brown wires looking for any that are damaged. Replace/repair as appropriate.

Out of curiosity, why did you remove the battery for charging?

[scud]

Thanks...just to bring it into the house, raining outside.

[Ethel]

I'd ignore the cable colours the -ve bolts to the boot floor by a short cable and the +ve (nearest the front of the car unless it's been fiddled with) disappears under the floor to reappear bolted to the solenoid.

Presumably the solenoid would try to throw itself in the wrong direction and nothing much would happen?

[scud]

thanks ethel, i think it may have been a bit more serious than that.

Just checked all the fuses they are ok. When I turn the ign no lights, then after a while they ign lights come on, but won't even try to turnover. No radio, no headlights etc no nothing. which i why I am thinking coil. Although I am no auto electrician.

DK what are fusible links? (if they are the fuses in the little sleeves i've checked them)

[ginigwunkle]

could have blown the solenoid, but no power went through this it just went through the battery earth-body could this wire have melted?

have you checked?

[scud]

I check the -ve batt strap and looked ok, also connected jump lead to body and would not jump so reckon not that. Unless of course you talking about a completely diffrenet wire in which apologies and can you explain where it is

Ta

[ginigwunkle]

have you tried another battery to start?

also starter? take it off and connect up to power of another battery to spin it up, if nothing then you kiled that....

[Ethel]

Could you have reverse charged the battery? The only thing I can think of that would cause everything to die is if you fried the insulation on the battery cable and caused a major short circuit.

[cambiker71]

thanks ethel, i think it may have been a bit more serious than that.

Just checked all the fuses they are ok. When I turn the ign no lights, then after a while they ign lights come on, but won't even try to turnover. No radio, no headlights etc no nothing. which i why I am thinking coil. Although I am no auto electrician.

DK what are fusible links? (if they are the fuses in the little sleeves i've checked them)

Do the lights slowly appear, and very dimly and when you turn the key to 'start' they go out? Sounds like the battery is faulty, sometimes if the battery has been overdischarged then it can be damaged beyond recharge but will slightly recover with the ignition left switched on, what sort of charger did you use? Most of the cheaper chargers won't even touch a completely flat battery, if it's that flat then often even a jump start won't get the car going as the flat battery will attempt to take all the charge the donor cars battery can supply, if possible try another charged battery. As for connecting it backwards, hopefully it won't have done too much damage to any of the electrics like the stereo and electronic ignition, but you should have the ignition/ oil pressure lamps on at the very least and be able to turn the engine over on the starter even if it doesn't fire due to ignition damage.

[dklawson]

Neither the solenoid, the starter motor, or coil are polarity sensitive. Though I work more with the old stuff this would apply to new components as well. Neither the starter motor nor the solenoid require any attention when you swap a car's polarity from positive to negative earth. You do swap the coil low-tension leads but that is to maintain spark voltage... not because you'll burn it up with the wiring reversed. What will be affected by switching the polarity are the components like the alternator. However, you could have fried the radio and perhaps a tachometer if fitted.

Fusible links may or may not be on later model Minis, they were not on early cars. The fusible link is a large inline fuse on the auxiliary wires connected to the battery (and/or starter solenoid) from the alternator. The more I think about it... it's unlikely that BMC/BL/Rover ever used them on the Mini... just forget I mentioned it. After you've sorted this problem out you can Google "fusible link" if you're still curious.

Scud, you mentioned that the ignition light slowly starts to glow after you turn the ignition on. You did NOT mention if the starter turns over or not.

The following test is STRICLTY to see what's been damaged, and the car should NOT be started during this test.
Disconnect the plug from the alternator. Turn on the ignition but do NOT try and start the car. Try your accessories. Does the radio work now? Do the headlights work? How about the horn, brake lights, and turn signals? Try all these things with the alternator UNPLUGGED from the harness. If you find all the other bits work, pull the coil high-tension wire and try to turn the engine over on the starter. Only do this with the coil unplugged so the engine doesn't start... all you're testing is the starter operation.

Though I still suspect the alternator is the damaged component... you should NEVER try and run a car with the alternator unplugged from the battery. You will damage the alternator if it isn't already. Again, the tests above should be performed with the alternator unplugged but under no circumstances should you start the car with the alternator unplugged.

[scud]

Awesome cambiker, took old batt out connected jump leads direct to batt leads and it fired up.

the fact that i connected it wrong way round was throwing me, never thought the batt was not properly charged had it on trickle for 2 days

Thanks again

[scud]

sorry should have thanked everyone else for their input, 10 years ago haynes was my only option to work through bit by bit, in't tinternet ace!

[dklawson]

Don't forget to post back with your findings once you sort this out.

[scud]

To clarify, connecting wrong way round actually cause no damage, it was not starting becoasue the battery had not charged fully even after being on tricle for 2 days. I was unaware that a super falt battery will draw current from a jump rather than starting the 'patient car'. Removed 'flat' batt and jumped straight onto battery streaps and fired up immediately

Ta