MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

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 GT V8 Factory Originals Technical - Misfire in wet/damp weather

My Factory V8 has been plagued with a misfire in damp/wet weather, I have changed the following:plugs, coil, points and condensor,dizzy cap and rotor, H.T Coil,leads and plugs, and it still happens, today I was staring blankly under the bonnet listening to the engine chugging on 6 and a 1/2 cylinders-and noticed the (overflow?)pipe from n/side carb ended in a small puddle of water caught in the chassis rail junction, the other pipe was hangin down unobstructed, I moved said pipe and immediately exhaust note changed to a deep burble-misfire gone-I'm not sure if this was just coincidence as misfire does go eventually(usually after 10-15mins) I put the pipe back in puddle but car still ran o.k,I have extended pipe to hang down unobstructed, but I cannot see how it was to blame-any ideas??
N.T Griffiths

Try at night with the lights out, looking for sparks or corona discharge. Is dwell OK? Overflow pipe is almost certainly a coincidence.
Paul Hunt

I have a similar problem with my conversion - just occasionally the engine will run roughly and miss on a couple of cylinders - then next time I start it up it is all sweet again, happens irregularly - it is not damp in the dizzy or bad leads / plugs, I have ruled these out by subsitution with new items.
Chris Betson

Drove car to work this morning, cr*ppy wet weather (as usual)no misfire at all, this is the first time in months!!I had previously doused everything with WD40 as well-Could the n/side carb have been sucking up water from the overflow pipe?
N T Griffiths

I am thinking it is more of a backpressure issue. The overflow system was not designed to have any backpresure, si when it did when in the water it may have messed wiht he overflow valve affect fuel flow in the carb..? a carb overflow does not suck in anything, but if it had pressure pushing back into it (sloshing water) I could see it possible being problematic.. Glad she is running better
Larry Embrey

Cheers,

Problem is definetly solved, as weather has been wet and windy, engine is running better than ever.
N T Griffiths

This thread was discussed between 15/03/2002 and 20/03/2002

MG MGB GT V8 Factory Originals Technical index

This thread is from the archives. Join the live MG MGB GT V8 Factory Originals Technical BBS now