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MG Midget and Sprite Technical - Starting Problems

Hi guys, having starting problems now.....

I have tried checking the archive and have not yet found an answer so here goes (long story).

I have had the car for nearly three years and up to now, have not suffered any major starting problems (apart from a sticking starter motor and flat battery).
A month ago, I took my midget along to a rolling road to fine tune the carbs and satisfy my curiosity. Obviously the car was put through its paces but everything was fine and dandy on the longish drive home (70 minutes), no starting problems or anything. One week later and no go.
When I turn the key to the sprung position all I get is a worryingly fast mechanical/electrical clicking noise and nothing more. No starter motor turning or anything, completely dead.

I attend my local Spridget meet (end of last month) and get a couple of ideas from other members and get home for another 'play'.
Apart from unbolting the solenoid and refitting nothing else was tried. I went to start the car and same again. I thought, what happens if I turn the headlights on? Just a couple of single clicks from somewhere in the engine bay. I turn the lights off and wey hey, starter motor spins and she starts - a very happy little car. Wow, I though how very strange but happy that she is not working again.

Another week passed and though of taking her out for a drive, but guess what, same old symptons again.

What I have already tried;
1) I have changed the solenoid for a new one.
2) I have remove areas of paint under the mounting bracket to get a better ground.
3) I have bridged the two terminals on the solenoid with the ignition on (both new and old one) and apart from a few sparks, nothing else happens.

I have tried the headlight trick again, but all I have noticed is that the headlights turn off when the key is turned to the sprung position.
They do come back on again which are still bright at the normal position.

I am not sure whether the above is diagnosing an electrical problem or one that I have with the starter motor itself. Only hope one of you guys can assist a pretty useless novice.


Chris
Chris Guards Red Midget

Additional information.

I have just checked the voltage through to the white/red wire (side of the solenoid) and confirm that I have 12v when the key is turned to the sprung position.

Chris
Chris Guards Red Midget

the headlights behaviour sounds like duff battery
David Smith

Normally David would be about right but reading your total post it would suggest that the earth lead from your battery to the car body is not making a good connection. Make sure that the cable is secure and that the end that fits to the ar is clean and paint is not causing a poor connection on the body.

Robert (Bob) Midget Turbo

check(ed?)

battery - fully charged, topped up water levels on all cells

battery lugs - clean and protect against crud build up

battery leads and their terminals - clean, secure and protected, meter for resistance

earth leads (especially one from body to engine) - clean, secure and protected, meter for resistance

soloniod - all connections and wires clean, secure and protected

starter connection - clean, secure and protected

sorry Bob posted whilst I was typing
Nigel Atkins

Definite feeling we have discussed this all before recently!

But this time my diagnosis is that the starter motor itself is faulty.
When you turn the key to the "sprung position" the solenoid activates (hence the clicking sound) but the faulty motor is drawing too much current so that the solenoid then immediately releases again, and then reconnects and repeats this iteration with the starter, giving the rapid clicking sound.
The lights dim because the starter is taking all the current, although not spinning
The starter should have spun when shorting the two heavy terminals on the solenoid.

I suggest that you remove the starter and try it off the car, connecting direct to the battery with a pair of jump leads (one to starter casing, and one to the terminal). Put a booted foot on the starter to stop it going berserk across your garage floor! If it doesn't spin it is time to take it to part exchange for a new one. Or if you are frugal, to strip it, clean it and fit new brushes.
If it does spin, then the fault is somewhere else and I have been talking through my backside again.

Guy
Guy

Hi Guy

Just to muse over your suggestion.

If the starter motor was causing the problem then for the lights to dim the starter would have to be taking power and would therefore be a mechanical problem with the motor. If this were the case then when the key was turned or the solenoid shorted out the starter would hum like a sweaty sock :) Also I would expect the starter to turn normally when off the car so it may not be so easy to determine. I will stick with my post above but will wait with baited breath!
Robert (Bob) Midget Turbo

Thanks for all the tips. I have just spent the last hour or so searching through the Archive and together with the above, now have a good idea what to go for.

I am sure that the battery/body earth is good as it was only last summer that I redid that connection.

The battery I would say could be suspect as it had gone flat over the winter months.

The engine/ground is secure and in good condition but totally covered in oil (leaking 'A' Series).

Will definitely get the starter motor off and check that out.

Chris
Chris Guards Red Midget

Sounds like a duff starter. We had an early Sprite with the same symptoms at work. Checked the connections, solenoid, etc, swapped starter motor and fired up fine.
The old one had been stood a while and seemed to have siezed up a little, also the brushes were a bit oxidized.
If you take your starter off, before you 'write it off' try removing the end plate and making sure it's turning properly and the 4 brushes connecting well.
RoadWarrior

Chris

>>I am sure that the battery/body earth is good as it was only last summer that I redid that connection<< never assume, check it, things happen over time, mistakes could have been made originally

>>The battery I would say could be suspect as it had gone flat over the winter months.<< check water levels and battery is fully charged


>>The engine/ground is secure and in good condition but totally covered in oil (leaking 'A' Series)<< check for resistance

Guy and Bob are very good at diagnostics but I think, and I could well be wrong, and no disrespect to you Chris as I do it too often but, your original post is a bit confusing to pin something down so it's start with the basics which are always worth checking even if not the cause of this problem they could highlight potential future problems

The reason Guy said it's familiar are a couple of previous threads

You'll need to read ALL the way through to fully understand the need for a logical diagnostic path :-

http://www2.mgcars.org.uk/cgi-bin/gen5?runprog=mgbbs&mode=thread&access=&subject=97&source=T&thread=201102241706042852
Nigel Atkins

Hi guys

Important update. Last night I put the battery on charge, its had about 22 hours of charging.

Just fitted it back into the engine bay, cleaned the terminals and connections.

I was expecting the clicking but success, first turn of the key and the starter wound up, choke out and fired.....GREAT.....

I have seen other threads of diagnosis where the battery has been disconnected (which this was) reconnected and started, only to fail again.
So fingers crossed with you guys help we have nailed the problem to a dodgey 3 year old battery.

I will try starting the car again on Sunday with a view to replacing the battery next week.

Fingers crossed. Lets hope this has been well and truly nailed.

Chris
Chris Guards Red Midget

Well done Chris.
Although I was wrong in diagnosing a faulty starter, I am pleased for you.
Since you reported having an uneventful 70 minute drive home the week before I had expected that would have fully charged your battery. So it is possible that the battery isn't holding its charge for long. But the solution is clear - you just have to drive it every day! ;-)
Guy

Which terminals and connections did you clean?
Robert (Bob) Midget Turbo

This thread was discussed between 17/03/2011 and 18/03/2011

MG Midget and Sprite Technical index

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