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Midget cutting out

Posted: Fri May 30, 2014 10:49 pm
by brownnova
So today I bought an MG Midget! Hurrah!!! Back into the classic world after a good few months of looking to replace my Porsche 924.

Bad news however is that it arrived at my house on the back of a green flag van :(

Was running well, then started idling a bit low. We got stuck in some traffic, and it felt like it wasn't firing on all cylinders as I was moving off. But we got going and it seemed Ok, but a bit lumpy. Next set of traffic lights it cut out, and refused to restart - cue some pushing!

Set about testing the plugs, leads, rotor arm fuel line etc - all fine. Hour or so later - fires up OK - still idling a bit low, but with a bit of choke sounds good again. So off we go, until 5 miles down the road - exactly the same thing (lumpy, traffic, cut out) happens. Cue more pushing...

The green flag man suggested it could be the points? Any ideas at all? Does this sound plausible?

I'm a bit stumped (I've never had a car with points I don't think!) And I'm slowly realising what my wife keeps telling me, that I don't know as much about cars as I think I do! :roll: :lol:

Thanks

Re: Midget cutting out

Posted: Sat May 31, 2014 9:46 am
by Luxobarge
What year/engine have you got?

Re: Midget cutting out

Posted: Sat May 31, 2014 3:08 pm
by suffolkpete
Sounds like a dodgy coil or cheap after-market rotor arm failing, but I would always start by cleaning/replacing and gapping the points before digging deeper. You need to do some fault finding when it has actually failed. Check for a spark at the plugs, if none check that there is a spark at the king lead from the coil to the distributor during cranking. If there is a spark, then replace the rotor arm, otherwise it is probably the coil or condenser, but these can only really be checked by substitution.

Re: Midget cutting out

Posted: Sat May 31, 2014 6:19 pm
by brownnova
Hi,
It's a 1980 1500.
U
I changed the condensor, and had a go at cleaning the points, but today after it started straight away the idle got lower and lower and it cut out... Thankfully got no further than my road...

Re: Midget cutting out

Posted: Sat May 31, 2014 9:23 pm
by Luxobarge
OK, so it's the later rubber-bumper one with the Triumph engine.

From that latest description it sounds as if it might be fuel related. I would a) check the fuel pump and b) when it fails, immediately open the bonnet, take a plug cap off and check for a spark. If you're still getting sparks, it's a fuel problem (and vice-versa) - you need to pin it down to one or the other and then take the diagnosis from there.

Re: Midget cutting out

Posted: Sun Jun 01, 2014 1:08 pm
by rich.
did the recovery chap try to fix it?

Re: Midget cutting out

Posted: Sun Jun 01, 2014 1:54 pm
by UKJeeper
Vapour lock?

Re: Midget cutting out

Posted: Sun Jun 01, 2014 3:45 pm
by Luxobarge
UKJeeper wrote:Vapour lock?
I think he'd get further than the end of the road if it was that. And they're not particularly prone to it so long as all the heat shields etc. are in place.

Re: Midget cutting out

Posted: Sun Jun 01, 2014 5:01 pm
by brownnova
rich. wrote:did the recovery chap try to fix it?
First time yes, second time I just wanted to get home! As it had spark etc, I'm thinking fuel. It had been stood for a little while prior to it's body resto, so I'm thinking carbs may be at fault.

Re: Midget cutting out

Posted: Sun Jun 01, 2014 6:20 pm
by Luxobarge
OK, so when it fails it still has a spark?

In that case, favourite for me would be the fuel pump - does it still have its original fuel pump? If so, then the points in it probably need cleaning. Not too hard to do - take it off and get the working end of it apart and cleaned up, replace them if they're worn and burnt.

Alternatively you can get a solid state pump which is a direct replacement and should give no further problems - that's what I did.

Or it could just be something as simple as a fuel blockage - does it have an in-line fuel filter, and if so do you get a good flow of fuel through it with the ignition on?

You need to get out there and test some of these things and we can take the diagnosis from there.