Ignition problem

[grimspeed]

My car is a 69 1100 .
I turn the key . My ignition light comes on.
I turn it further for the starter and everything cuts out !
Any ideas ?

[DAVIDMCCULLOUGH]

Hi, has it been running ok up until now?

Possibly a flat battery? Give us some more info and maybe we can help!

[grimspeed]

All has been fine ! Its like something trips out ! wiggle the wires around the fuses and the ignition comes back on then as soon as you hit the starter everything cuts again . The battery is fine !

[simmitc]

How do you know that the battery is fine? What tests have you done? Is there good power with the ignition on and before trying to start - headlights nice and bright with the heater fan running, wiper still working? Hydrometer? Voltmeter?

Does the solenoid click when you operate the key?
Is the engine free to turn on the handle?
Have you made sure that the starter has not jammed in the engaged position?

IF the battery is OK, then, when you turn the key, something is taking all the power. Culprits are the solenoid and the starter motor. With the car in neutral and the ignition off, use a battery jump lead to short the two large solenoid terminals together - be careful to not touch anything to earth. If the starter now spins, then the solenoid is faulty. If the starter does not spin, then the motor is at fault.

[bmcecosse]

This generally indicates bad connections at the battery - or the earth lead connection. Or perhaps an internal fault in the battery. But the fact that 'wiggling' terminals brings the lights etc back on - pretty much confirms bad connection problem. Note that the Ign switch doesn't go through any of the fuses - but wiggling the fuse wires must also be moving the battery connections. Just check that the starter is free to turn (spanner on the square sticking out the end) - but if that was the case - the lights would come back on immediately you released the key - without need for any wiggling.

[grimspeed]

All ok now . It was a flat battery ! Had a bad storm here on Wednesday and water must have got to the wiring and flattend her.

[bmcecosse]

How can water flatten the battery? Look for another cause.....

[alexmcguffie]

Water can easily flatten a battery! I have a friend with a Honda where in a heavy storm, water gets in the door electrics and flattens the battery overnight.

Also, never put an electric fire in the bath (full of course!) or it will run your electricity bull up....

[MarkyB]

We are talking about Morris Minors here, modern cars have rather more gadgets and wiring which all equate to possible points of failure.

[bmcecosse]

I don't accept that 'storm' rain water will flatten a Minor battery.....try again. (Nor do I accept it flattens modern car batteries either - otherwise 50% of cars wouldn't start in the morning...) Water is non conducting - is would need to be salty... The electric fire suggestion is irrelevant since it would involve AC current at lethal voltage - a very different beast to a car battery.....

[alexmcguffie]

Rain water does cause problems with car electrics, old or new. It is a fact that I have seen many times in my line of work which is why we design against it. Whether people believe it of not...... I am only passing on my professional experience to someone with a problem.

[bmcecosse]

In the long term it can of course cause corrosion of terminals etc - but it doesn't flatten batteries...... How would it even reach any of the Minor electrics?? Can you explain just how it could flatten the battery?? Anyone else on here had their battery go flat after a bit of rain?

[kennatt]

Well never heard of it either,from my limited knowledge of electrickery,the only way water could cause a discharge is where it forms an earth, to a permanent live feed,where on a minor are there any permanent live feeds where water could make the connection,except the solenoid,and feed to the ignition switch ,Everything else is switched off.Could enough water get to the solenoid,and to the ignition inside the car,doubt it. Unless the top of the battery was wet would that cause it,again how would it get there.So like Roy, would love to have it expained. Not bothered about moderns,don't have one,and unlikely to ever get one.

[alexmcguffie]

Whatever car you drive be it McLaren P1 or Minor I= V/R This is basic principles that can not be argued with.

Secondly, electrical insulators break down with age/use etc, distributor caps are an obvious example but I've also seen it with condensers in the past. An inefficient insulator will conduct more than a good insulator.

Classic car electrical connectors aren't generally well insulated from the elements. At a quick look, items connected to +12v with the ignition off are:

Interior light + switch
Horn + switch
Control box
Starter solenoid
Light switch
Dynamo

A breakdown of insulation amplified by damp dirty conditions could and has caused batteries to discharge over night. This would be even more pronounced with an old tired battery. This can be tested by removing the battery feed fuse (always live) and insert a mA meter with everything switched off. Check for leakage current on a dry day then compare it with a wet day.

[bmcecosse]

Hard to see how rain (and it would need to be 'salty' rain) could get to any of these....and since W = IIR - any worthwhile current leakage will cause heating.....setting the car on fire. Since this is an extremely rare happening (even rarer than a storm discharging a battery...) and bad/tarnished connections don't cause current leakage (quite the opposite) - this was not what happened here. The dynamo is NOT live in any way with Ign off. But what CAN happen - is that the Regulator contacts may have stuck in - this bleeds current away through the dynamo - and the 'IGN' light may not have been noticed - staying on after the Ignition was switched off. Otherwise it's just a simple 'something left on' situation.

[MarkyB]

Chemistry isn't my strongest subject but I have a feeling that some of the products of corrosion particularly on the battery connections will be salts.
Also in winter there may well be traces of road salt just about everywhere on the car.

http://en.wikipedia.org/wiki/Salt_%28chemistry%29

any worthwhile current leakage will cause heating.....setting the car on fire.

I can't see it going from problem to disaster quite that fast, wouldn't the connection dry out first stopping the power leaking?

[bmcecosse]

Exactly!