[COLVERT]

Originally Posted by Yorkshire GOC

Had AA Man to look at battery - which i have never been happy with - tested again and all fine reading 12.4 - which i always thought was the minimum resting voltage? - but he also ran other tests and the battery is OK .

However he tested the battery with the engine on - and as he turned the ignition you could here the distinct crackle/snap of a spark - he immediately said my HT Leads are discharging to earth - and that's causing the misfire -so pleased i called them out albeit for a different reason - will get new leads and packs ASAP . One simple diagnostic to remember for the future.

The discolouration at the battery terminals means there is a slight acid leak coming up around the pillars themselves.

This, however, does not mean the battery is defective in action, just that there is an acid leak.

Spark plug leads should be well away from any metallic parts of the engine. Even new leads if looked at in complete darkness can show faint arcs to earth.

The spark will ALWAYS take the easiest route. If the leads are starting to age the spark will jump through the insulation. However if the lead is well away from any earthing point the spark will go to where it's supposed to go.--