MGB Register Forum

So today I removed the electronic module and checked the wires thoroughly. Considering this unit must be 4 yrs old it still looks as good as new. I replaced, checked the baseplate was moving freely of all wires and fired up to 3000 revs. For a minute I thought the problem had gone. But gradually as ...

I have manually checked the movement of the base plate, also sucking the vacuum hose operates everything as it should. Checked hose connectors at each end.
I have a new set of points on the way so will fit them if nothing else works, though the electronic module worked great and was totally reliable ...

I misunderstood Vic... learning stuff here.So as you say, it all points to the vacuum/ baseplate movement being the area of concern. Ill look into this in the week..fingers crossed

I agree, everything saying baseplate movement
Is the problem. But vacuum removed, the baseplate still moves with the weights. So why wouldn’t it misfire then ?

I’ve replaced plugs with new v recently with ( NGKs ) ready for summer so very few miles on them.
The misfire happens without load in the workshop. Nothing at idle, but gradually kicks in
More as revs are increased. Holding the revs
At 3000 the misfires seem to increase.

Charles,
I’ll check the plug gaps just to be sure.. 035
From memory. But as I’ve said she’s fine with the vacuum off, and with or without vacuum,
no misfire at tick-over.

I wondered about going back to points. I think it’s got to be worth a try so I’ll get into it next week. I’ve had another look at the LT wires and all appears fine.
My understanding is that the Centrifugal advance kicks in with more revs and the vacuum drops out as the throttle is opened. This all ...

Hi to all,
I own a 72 bgt which has developed an irregular misfire which gets worse at higher revs. What makes it particularly interesting is that by removing the vacuum advance pipe and plugging at both ends will remove the misfire completely. But I don’t want to run without the vacuum advance ...