Whitish residue in exhaust?

[Radar]

G'day all,

Today when I was cleaning out my boot, I noticed there was a whitish residue in my exhaust pipe. It's hard to describe really, but it's there. My first thought was maybe it was from when I washed the car the other day, but I'm doubting it. Google doesn't turn up much, other than saying it's possibly water or coolant leaking. Anyone had any ideas or had something similar?

It's a 94 VR Acclaim, Series I, running BP Ultimate. All my fluid levels are fine, no shortage of oil or coolant.

 

[hako]

You're probably worrying about nothing. Maybe your last tank of fuel contained ethanol which can alter the exhaust gas residue colour. Also, the colour of exhausts and spark plugs are no longer used as a guide to engine condition since the introduction of unleaded fuel except in unusual instance such as coolant leak or cat meltdown.

 

[johnnyk]

You're probably worrying about nothing. Maybe your last tank of fuel contained ethanol which can alter the exhaust gas residue colour. Also, the colour of exhausts and spark plugs are no longer used as a guide to engine condition since the introduction of unleaded fuel except in unusual instance such as coolant leak or cat meltdown.

Cat meltdown? LOL. I would still think black exhaust indicates the engine is running on a lean mixture of fuel. What about the spark plugs, can anyone confirm this? I'd imagine you can still tell by the spark plugs if the engine is running rich, burning too much oil, etc?