8 replies to this topic

[duff_liam]

Hi, i have been doing a auto to manual conversion for a while now. everything is in and ready.
HOWEVER
trying to start it last week and a few of the electrical cables burnt out. The ones that burnt out were:
cable from negative side of coil to fuse box
and
coil to distributo cable.
does anyone have any idea why this is happening? the car turned over but would not start up.
got a spark at distributor but not at plugs. replaced disributor cap, rotar arm points and condensor today.

My wiring set up for coil is:
negative side: 1 cable to distributor
1 to fuse box one to what looks like a condensor on side of coil. (dont know name.)
on positive side it a cable going to the box to left of engine bay. where main battery cable is.
sorry if descriptions are crap this my first mini and i am a novice.
any help is grately appreciated.

[me madjoe 90]

Is the new engines igntion system use a balsted coil? is it from the same year car?
Balsited igntion systems have two feeds one for cranking from the soloniod this copensates for low battery voltage produced when cranking. And one for normal running that has a resistor droping the voltage this means a balisted coil normaly runs on a lower voltage than 12v...

A normal un-balisted ignition system just has one live feed from the ignition live and would suffer a poor spark on cranking due to the coil being designed to run on 12v not the lower cranking voltage.

Year and model of car could help alot more. Mainly year though.

Also what colours are the wires? As its all well and good saying a wire from the fuse box, but it could be any of the many wires from the fuse box.

Edited by me madjoe 90, 28 February 2011 - 08:47 PM.

[L400RAS]

My wiring set up for coil is:
negative side: 1 cable to distributor
1 to fuse box one to what looks like a condensor on side of coil. (dont know name.)
on positive side it a cable going to the box to left of engine bay. where main battery cable is.
sorry if descriptions are crap this my first mini and i am a novice.
any help is grately appreciated.

This sounds wrong... and you now may have a damaged coil.

Please state age of the car, and colours of wires you have. Also, a photo of the coil connections, and the condensor, and "the box to the left of engine bay" part...

Connections to the coil should be:

POSITIVE SIDE:
White OR white with pink.
You may also have a white with yellow. Depends on model.

NEGATIVE SIDE:
White with black wire - goes to distributor.
Another white with black goes to the rev counter (tachometer) - depends on model.
The condensor goes to the negative side. This reduces radio interference. You can leave this disconnected while you are trying to start the car - it will not affect the running of the engine.

final Edit: updated information back to original (correcT) for any future readers).

Edited by L400RAS, 01 March 2011 - 07:35 AM.

[me madjoe 90]

The condensor goes to the negative side. This reduces radio interference. You can leave this disconnected while you are trying to start the car - it will not affect the running of the engine.

This statement is incorect the condenser or capaciter as it should be called is there to try and stop the spark/arching of the points as they open.

It dose this by taking up some of the voltage produced in the primary winding when its magnetic field colapses. If this was no here or not functioning the full amount of this voltage would jump across the points to earth. Effectivly arcing them away and resulting in points failure and poor ignition timeing, also a syimptom of not using the capacitor would be a weak spark .

Edited by me madjoe 90, 28 February 2011 - 08:31 PM.

[L400RAS]

The condensor goes to the negative side. This reduces radio interference. You can leave this disconnected while you are trying to start the car - it will not affect the running of the engine.

This statement is incorect the condenser or capaciter as it should be called is there to try and stop the spark/arching of the points as they open.

It dose this by taking up some of the voltage produced in the primary winding when its magnetic field colapses. If this was no here or not functioning the full amount of this voltage would jump across the points to earth. Effectivly arcing them away and resulting in points failure and poor ignition timeing, also a syimptom of not using the capacitor would be a weak spark .

Edit: See Dan's post #8, he backs my statement up - this part is for radio interference, and not required for running of the engine.

Edited by L400RAS, 01 March 2011 - 07:36 AM.

[me madjoe 90]

oh



I will amend my post to hopefully stop the OP from reading incorrect information.
thanks

It is ok hope i helped abit. Only reason i realy posted as i found all this out today doing course work on the kettering ignition systems.

Shame the O.Ps not put there year up yet, but im sure they might be able to figure it out.

I know how it works and should be wired but not the wire colours can look them up though.

Edited by me madjoe 90, 28 February 2011 - 08:44 PM.

[duff_liam]

The car is a 1983 mini Mayfair the wires that burnt out
are the black and White one (coil to
distributor) and a solid
White one (coil to
fuse box) I will
get pictures up asap. Thanks
for all
advice. Any ideas now u know a bit more info??

[Dan]

Oh dear there's a lot to clear up here.

A condensor is a capacitor that is part of the ignition system LT circuit, it quenches current and increases coil energy as said above. Importantly however on Lucas dizzies the condensor is INSIDE the dizzy. A capacitor on the outside of a Lucas dizzy, usually clamped under the retaining screw and connected to the LT coil terminal is as said above a radio interferance supressor. It can be left disconnected for trouble shooting.

A Mini ballasted ignition system must have both the pink/white ballast wire AND the white/yellow bypass wire connected to the coil positive. Both are required, they are not optional. The bypass supply is the whole point of having the ballast in the first place. If the system is not ballasted it will have plain white supply only, using a single supply cable.

There should not be any connetion from the coil LT (negative) terminal to the fuse box, not ever under any circumstances. The wires have melted because you have bypassed the coil by fitting the white coil supply cable to the coil LT and shorted it straight to earth through the dizzy. This won't have damaged the coil but probably fried the points and condensor. Did a fuse fail? If not it implies that the connection at the fusebox was on the supply side and you may have melted wiring right back to the ignition switch and beyond. You need to inspect a lot of your wiring now.

[me madjoe 90]

[quote name='duff_liam' date='Feb 28 2011, 10:32 PM' post='2066606']
The car is a 1983 mini Mayfair the wires that burnt out
are the black and White one (coil to
distributor) and a solid
White one (coil to
fuse box) I will
get pictures up asap. Thanks
for all
advice. Any ideas now u know a bit more info??
[/quote

There should be a white wire going to the fuse box from igntion switch this should have a fuse Think its a standerd ignition live fuse is 35amp but the amp of fuse not stated on my diagram but could have been wrong size? . The white wire as you stated should then go from the fuse box as you stated to the coil posative side. The black wire from distributor should then conect to the negative side of the coil.

Were the points sat closed when you turned the ignition on you shouldent leave it on burns coils out, just to add could posibly have melted the wires from the prolonged curent flow.

Did this happen as soon as you flicked on the ignition, or a few seconds aferwards? If so id say there was a short to earth some where between the fuse box and posative on the coil. Or posibly even directly inside the coil.

Still dosent explain why the fuse dident pop altho if its a 35amp fuse it might not have been enougth current to pop but still melt stuff .

I belive yours is an un-balisted system so id be tempted to get a un-baslted coil i.e one that says 12v on it and replace the wireing. Get a good and right one for the sytem fuse again im sure its 35amp should be the top one or the one with a green and white wires going to it and try it again.

You can cheak the resistance of your coil across its posotive and negative termanals to cheak the winding, if the resistance is shows inffinate or 1 on the multi meter then the coil is buggerd.


Or As dan Said because he seems to be the man when it comes to mini elecys good luck

All has to be said i tryed my best if not rambled on abit

Edited by me madjoe 90, 28 February 2011 - 11:19 PM.