Difficulty in hot starting injected Lycs is legendary & it ain't the
urban variety.

That said, I doubt that the problems are caused by boiling fuel, since
the best technique on the 2 I've owned was mixture at idle cutoff, full
throttle. Crank until it fires, then quickly swap lever positions:
mixture to full rich & throttle to idle. This implies flooding when hot,
not boiling fuel & vapor lock.

Someone mentioned moving the pressure regulator bypass from the injector
block to just downstream from the pump. If you do this, you lose
pressure regulation at the injectors. It will take some finite amout of
time after an open injector depletes some fuel & pressure for the
regulator at the other end of the fuel line to see the change & react.
It will take a finite amount of time for the fuel which is not moving in
the line to get moving again toward the injectors. Some injectors might
tolerate this with no problems, others probably won't.

Charlie

Jeff Spitzer wrote:

Maybe you have hit on the real reason that most regulators are at the fuel
rail and why this system is now possible.  If you simply measure the
pressure at the rail with a relatively fast sensor then you can adjust pulse
width to the pressure changes.  Since the computers and sensors are now fast
enough anyway its a net savings on cost of return lines, etc.  Maybe the
computer also holds the injectors open if the oxy sensor reads too lean on
hot start.  Otherwise I would expect maybe only a "minor" extended cranking
time but mostly objectionable rough running during startup.  Still I think
it would line up the old ladies at the service department.
\
Jeff Spitzer

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