MINI One - Puddle Trouble

Q
I have a 2003 Mini One and have had it for nearly a year now. The problem I have is that when I go through a puddle or lots of water at the side of the road it starts to misfire like the old ones used to do. I thought it was water getting into the air intake, so I have fitted a K&N, but it still did it the other day. Have you any ideas why this is happening?

A
This sounds like a typical case of water getting onto the electrical contacts for the ignition system. We spoke with several specialists who confirmed this could be the case. However, MINI Matt also suggested the HT leads could be breaking down. When you travel through lots of water, it finds its way up the back of the engine and onto the HT leads. If this problem happens again, try spraying over them with WD40. The other solution is to avoid large puddles. You quite rightly suspected that water is being drawn into the engine through the induction system, but if a sufficient quantity of water gets into the combustion chamber it can result in engine failure, so drive round deep areas of standing water or drive slowly through them.