MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - electrical 'miss'

1979 roadster...car was running like a top when i completely lost power. won't start. Ordered and installed new cap, rotor, wires and plugs. Started right up but now I have a very prominent miss at low "r's" and it is very minor at high "r's". I have an after market electronic ignition on this with a petronix coil. Ideas?
Peter Murray

Peter,
Is this a pertronix I or II. I have experienced similar problems with both set-ups despite using the specified coils for each. I finally had to abort using the Pertronix II and go with the Pertronix I and their 3 ohm Flamethrower coil. Also you need to bypass the balast resistor and bring 12V to the positive side of the coil. When I tried to leave the balast resistor wire in the set-up with a 1.5 ohm Flamethrower coil and the Pertronix I I still had the miss, especially after the car warmed up. Hope this helps. BTW mine is also a 1979.
Frank Mooring

That is a good question and I will have to investigate it..however I was running smoothly before I dropped what ever dropped, (cap, rotor etc.) I am wondering if I should back off the things I replaced to see if one of the new products is causing the miss. I.E., go back to the old wires, or re-install the old plugs but for some reason in the back of my mind i don't think plugs are the problem.
Peter Murray

This thread was discussed on 25/07/2007

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.