MGB MISFIRE

Author
Discussion

sb-1

Original Poster:

3,321 posts

270 months

Monday 18th September 2006
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Hi Guys,

Took my B to a local classic car event yesterday,it it ran sweet as a nut until on the way home,we stopped at the Supermarket.

When I re-started it started spluttering and missing.This appears to be heat related.

Any ideas?

Church of Noise

1,492 posts

244 months

Monday 18th September 2006
quotequote all
Could be the coil, is it still the original one? Also check the plugs and the plug leads.

IMHO, these are the first suspects (but then again, I'm not that much of an expert)

Fiskkeeper

151 posts

219 months

Tuesday 19th September 2006
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does it clear after a few mins running? that'll be fuel evaporation then. wrapping the fuel lines in silver foily tape & making sure the heat shield behind the carbs is ok will help. i believe unleaded evaporates much easier than the real petrol MGs where designed for which means most of them now suffer this.
i know my 1500 midget coughs/splutters/dies/stutters for about 2-3mins on restart if i stop it when hot & restart within about 10-15mins. holding the revs up cures it quicker as the cooler fuel from the tank gets to the carbs & cools the float chambers etc

sb-1

Original Poster:

3,321 posts

270 months

Thursday 21st September 2006
quotequote all
Cheers guys,

I have spoken to a local MG specalist in Ripley,they say it is most likely condenser,or rotor arm,or coil.

I will try this before I take it into them to look at.

Thanks

Steve

coco h

4,237 posts

244 months

Thursday 21st September 2006
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Points and condenser were always the fault on MGB GT - I kept on replacing the darn things

mucus

33 posts

223 months

Sunday 24th September 2006
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I found that replacing the points with an electronic ignition kit made my MGB run much betterclap

wadgebeast

3,856 posts

218 months

Monday 25th September 2006
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If it was points, condenser etc, it would happen all the time. It's a cheap fix and probably worth doing anyway, but your problem sounds like fuel evaporation in the carbs and the fuel line in the engine compartment.

As has already been said, check your heat shield is in good nick, and consider a)lagging your manifold and exhaust with heat bandage or b) covering your fuel lines with foil (shiny side out) to try and combat it.

Don't forget this is also a sign of a blown head gasket - the head can warp when very hot so you lose compression, the engine stalls and won't restart until it's cooled. so have a look at your head while you're there and see if there's any sign of steam / vapour leakage from the gasket.

heelantoe

43 posts

220 months

Tuesday 26th September 2006
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wadgebeast said:

Don't forget this is also a sign of a blown head gasket - the head can warp when very hot so you lose compression, the engine stalls and won't restart until it's cooled. so have a look at your head while you're there and see if there's any sign of steam / vapour leakage from the gasket.


I agree with this one. Had the same problem on mine and it turned out to be a head gasket had gone and the engine wouldn't restart until it had cooled down.
Was bad enough happening in car parks but the worst time was when it happened in an MG Rover garage car park right outside the spares department door. They didn't even come out to help!!!

sb-1

Original Poster:

3,321 posts

270 months

Monday 2nd October 2006
quotequote all
The engine/head is almost new(done about 5K miles)

The car doesn't stall,and always starts well.

I think most of it is down to lack of use,although I can't rule out fuel problems.

The specalist I spoke to though said,that 'B's" don't suffer from fuel stavation even the race cars.

What is most confusing is that the last couple of times I have used it ,it hasn't missed a beat!

wadgebeast

3,856 posts

218 months

Wednesday 4th October 2006
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Sticking piston in a carb?

sb-1

Original Poster:

3,321 posts

270 months

Friday 6th October 2006
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wadgebeast said:
Sticking piston in a carb?


Not being an expert on SU's you could well be right.

Whizz65

127 posts

217 months

Monday 23rd October 2006
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Hi

Just sold my B that I had for 21 years, the last few years I had this problem, as people say the petrol evaporates.

Check all the usual like plugs points condenser etc, and don’t forget the carbs.

I added additional heat insulation on the shield and wrapped the exhaust manifold, it was the SS sports free flow type and this solved the problem for me.

If you do wrap the exhaust manifold just check what’s near to the exhaust as it obviously makes the rest of the exhaust hotter.