Quote:
Originally Posted by Old Tele man
...with carburetors, a higher operating temperature helps ensure better fuel vaporization which leads to better fuel economy.
...but with todays' fuel-injection systems, this "vaporization" benefit is basically negated and overshadowed by injector pressure, which is now the major (but not the "only") factor.
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I agree with all that, but my fuel injection system is not quite like today's systems. My TBI is pretty much an electronic carburetor, more or less squirting the fuel in there with less-than-optimal atomization. Looking down the throttle body, you can see the fuel hitting the top of the throttle plate (the injector is in the middle, over the plate, shooting straight down) and some sitting on top of it.
That may very well explain the change, as the intake manifold is actually heated by some coolant passages.
As you said, that is not the only factor. It could also be tolerances tightening up with slightly warmer parts, could be the warmer oil having less resistance, could be the better vaporization. I don't claim to know all the reasons, those were my results.
On a side note, maybe if the better vaporization is the major factor in my increased FE, it would seem as though an injector cleaning/replacement could be in order.