Classic cars forum & vehicle restoration.

Finch661 · Posted: Thu Sep 17, 2009 10:25 am Post subject: Engine not starting in the cold

i have noticed recently (as it is getting a little bit colder) that in the mornings, my mg midget wont start. this only happens on cold mornings. the starter turns, but only a bit as if the battery was almost dead. the battery was charged recently (is a year old), and the alternator charges it.

is it possible that the cold is effecting the battery (how can i stop this)? i have noticed that my earthing strap needs to be replaced, but why would this cause a problem on a cold day, and not a warm day?

the car is fine when i jump start it using a portable jump starter! Sad

thanks
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1985 Mini Mayfare (1275)
1976 Mg Midget 1500

intransit · Joined: 03 Mar 2009 Posts: 14

the colder the oil the thicker it is and therefore the engine is harder to turn . I know this can affect things in midwinter but dont know whether it would have any relevance at this time of year !

Finch661 · Posted: Thu Sep 17, 2009 12:15 pm Post subject:

thats a good point, but then why would it start with a battery booster?
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1985 Mini Mayfare (1275)
1976 Mg Midget 1500

Nic Jarman · Posted: Thu Sep 17, 2009 12:28 pm Post subject:

Sounds like your battery has died. If it was a connection the booster would not help much. Do you still have the receipt?
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1936 Morris 8 Series 1
1973 MGB roadster
1977 MG Midget 1500
Dax Rush

Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

Connect a voltmeter across the battery and observe the voltage while trying to start. If it falls below 10.8 volts the battery is your problem.
The battery works by chemical reaction. Reducing ambient temperatures slows down the reaction and lowers the output voltage.
Now is the time of year when battery sales boom because batteries which staggered on in the (wonderful?) British Summer give up.

Another common cold start problem is resistance through the distributor circuit which reduces sparking voltage to the plugs. i.e. points, points base plate to distributor body and particularly distributor body to earth.
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Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

Finch661 · Posted: Thu Sep 17, 2009 2:06 pm Post subject:

thanks for the replies. unfortunatly, i dont have the receipt for the battery. its strange though, the last time this happened i thought the battery was dead, so placed the charger on it. within about 5mins, the charger said the battery was charged. i restarted the engine and everything was fine!

it has been great up untill this morning!
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1985 Mini Mayfare (1275)
1976 Mg Midget 1500

47p2 · Joined: 24 Nov 2007 Posts: 2009 Location: Glasgow

It could also be caused by a lazy starter motor, in which the booster pack gives it that little extra kick to spin it over a bit faster
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ROVER
One of Britain's Fine Cars

Finch661 · Posted: Thu Sep 17, 2009 3:00 pm Post subject:

thats an interesting point. the only issues i have with the starter, is that sometimes it has to be "tapped" with a spanner to get it to engage, apart from that its fine!

anything i can do with a lazy starter?
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1985 Mini Mayfare (1275)
1976 Mg Midget 1500

47p2 · Joined: 24 Nov 2007 Posts: 2009 Location: Glasgow

If your tapping it to engage it's most likely a dirty bendix. remove the starter and de-grease the bendix with white spirit or similar, do not use any oil before refitting....
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ROVER
One of Britain's Fine Cars

Finch661 · Posted: Thu Sep 17, 2009 3:25 pm Post subject:

excellent, would that cause bad starting? is it an easy job?
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1985 Mini Mayfare (1275)
1976 Mg Midget 1500

47p2 · Joined: 24 Nov 2007 Posts: 2009 Location: Glasgow

You need to remove the starter to clean the bendix. Not sure if it will cure your problem but it's a cheap fix and worth a try. If however the starter motor is old and tired then this will not fix it
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ROVER
One of Britain's Fine Cars

Finch661 · Posted: Thu Sep 17, 2009 3:49 pm Post subject:

hmm well the starter is the original i think, though my car has only done 14000 miles. i will take it out and clean it up.
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1985 Mini Mayfare (1275)
1976 Mg Midget 1500

ukdave2002 · Joined: 23 Nov 2007 Posts: 4105 Location: South Cheshire

Finch661 · Posted: Thu Sep 17, 2009 4:38 pm Post subject:

i will have a look and see if the battery needs topped up. the charging voltage is around 13-14V, i have a TIM voltmeter gauge in the cockpit, and there is def some charging going on!
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1985 Mini Mayfare (1275)
1976 Mg Midget 1500

Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

The charging voltage is not really a clue unless you have a high load switched on such as main beam or heater motor. Then it should be around 14.6volts.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!