I have a 156 T Spark, 51 plate. Whenever I start up the engine for the first time every morning, I get a sort of wheezing sound after I've tunred the ignition on and a split second before the engne starts. I think it sounds like a wheezing sound but dunno what other description to give it!!
It had it's 3rd service about 4 months ago. The noise only happens when the engine is cold. When it's warm and I turn it on then there's no noise!