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MG MGB Technical - my mgb keeps cutting out - help!

I just got my MGBGT this saturday. She was fine when I drove her home but then started stuttering as if she was going to stall (happened at different speeds and in different gears). Got her home but the next time I tried to start her up she did start but stuttered and almost immediatly cut out and stopped starting altogether.
We thought it might be the ignition and so replaced somoe of the bits and pieces and she worked again but about 10 miles down the road she started to stutter again and cut out. Now she won't start again.
When she stutters the needle on the rev counter goes mad, hopping from bottom to top and she sounds like she's struggling for fuel - anybody any ideas whats wrong with her?
We checked the fuel lines and filters and stuff and it all seems fine.
Any help would be great, I've only had her a few days and I still haven't been able to take her out for a proper drive!
Thanks
Caroline Merrick

my mgbgt did exactly the same when i got it a year or so ago. mine had been standing still for a fair time, and presume this would have contributed to the problem that i eventually found. it would drive fine, then at random intervals lose all power in a kind of gradual fashion over about 10 seconds. then left it for a minute and away it went again. I too blamed ignition etc - turned out to be the fuel pump, which eventually gave up completely a few weeks later. what mislead me was that i expected the pump to either work or not work, didnt know that whilst on the way out it would have good and bad days. that said, i am a total novice at this lark, so before blaming the pump i would wait up for one of the real experts to sort you out - they have all the answers.
mick
m rae

Very likely that horrible SU fuel pump. The only bit on MGB's that I don't like. Others cherish their idosycratic ways.
See the MITSUBA fuel pump thread.
Pump is located near the rear axle. You should be able to hear it clicking when the ignition is on.
Try unhooking the fuel line to the carbies and running (if it will run!) petrol into a container to check the regularity of the pump. Take care with ragard to static electricity, sparks etc
Peter

Mine had been standing for a while too so it's a possibility.
I'm a complete novice too but have a a friend who's helping me out so I'll get him to have a look.
Thanks for your help
Caroline Merrick

I think the giveaway here is that tacho goes mad; it signals a problem with the low tension 12v circuit. Try looking for a broken wire on the circuit to the coil and from the coil to the dizzy and also check the terminals on the coil itself are tight. Have a good look at the thin flexible earth wire inside the dizzy between the points plate and the case. If those are all OK, check the ignition switch.
Steve Postins

Steve is correct. The circuit from key to coil is White wires, and there are several places where a bunch of them come together. There will be at least one bunch under the dash where the wires come from the keyswitch, and another on the inner RH wing panel. These wires feed the tach, fuel pump, and the ignition circuit, and indirectly, everything that goes on and off with the key. Bad connections at these points is easy to fix, requiring cleaning of the bullet ends and possible replacement of the connector sleeves. Especially common on cars that have sat. Since this is a widespread but cheap and easy thing, that also applies to all other electrics, you may as well learn to fix it.

For this and your other thread as well, An excellent source of info is Paul Hunt's "The pages of Bee and Vee", http://www.mgb-stuff.org.uk/ Follow the links around for much education. Happy motoring!
FRM
FR Millmore

To troubleshoot the fuel system, see my article on fuel delivery troubleshooting guide at: http://www.custompistols.com/cars/dave/ddFuelDeliveryTroubleshooting.htm
That said, I agree with Steve and Fletcher, that the symptoms appear to be more electrical in origin and Fletcher has directed you to the absolute best source of information for that. Good luck - Dave
David DuBois

Also -

Check the brown lead wire at the starter soleniod.

On my car, it's held on by a push-tab connector.

When it wriggles loose, the tach needle flickers
and drops dead - along with the engine.
Daniel Wong

Had a simolar problem --- driving along just fine, then it would die, not starter, lights, horn etc. Turned out to be a loose/dirty connection of the heavy brown and brown yellow wires in the voltage regulator -- fuse holder area.

As mentioned, when the tachometer goes crazy, it's an electrical problem. As also mentioned, clean and tighten wire connections --- BUT -- disconnect battery first.
glg

Although this does sound like a failing fuel pump to me as well. I would like to know the year of the car, and does it have points type or electronic ignition.
Cheers Ric
R.A Willis

Thanks to everyone for their help.

We found a wire by the ignition that wasn't connected to anything which we put back in and the car started but when we took her round the block it stuttered and cut out again.

Then we found a loose connection going to the distributor and fixed that and she seems to be working ok now.

Just going to keep my fingers crossed and take her out for some longer test drives tomorrow.

Thanks again for all your help, to a begginer this forum thing is great! To a begginer like me its invaluable.

Caroline
Caroline Merrick

This thread was discussed between 13/09/2006 and 16/09/2006

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