'Carb' Icing

Theory would suggest that fuel injected engines should not suffer from icing. It is the evaporation of the fuel in a carb that lowers the temperature of the air to the point that the moisture in said air freezes and builds up on the throttle valve. As most injection systems inject the fuel directly into the intake port, the temperature of the air does not drop far enough to cause icing.

On the other hand, many injection systems do not have intake air preheating (eg puliing air in from a shroud over the exhaust manifold). In the current cold weather we are experiencing, the cold air entering the engine could cause ice formation on the throttle plate. Many throttle bodies on injected engines have a water jacket plumbed into the coolant circuit, so I guess the manufacturers believe ice formation is a possibility. All 1.8/2.0 Vauxhalls with multi-point injection have this, as far as I can remember.

HTH

Anthony Remove eight from email to reply.

Yep, the drop in pressure will gice a fall in temperature so if it's cold enough & foggy you can just achieve it.

Yes- you can get the injector tips forming ice and the spray pattern being interferred with plus cos of the cold poor atomisation so a harder to ignite mixture- especially at light loads / low revs where the mix is likely to be leaner.

Can you arrange some hot air?

Tim..

It's too cold to go fiddling about under the bonnet at the moment, but I'll take a look when I can - I'll probably find that there's a vacuum pipe come lose so I'm not getting a warm feed from the manifold or something.

Think most have a water heated butterfly surround.