[Vwdiesel] Why gasss cars mpg sucks (fwd)

[Roger Brown]

Roger Brown wrote:
> Should no be a problem, at least on the IDIs.  The fuel cutoff solenoid 
> is really mis-named, when off it just bleeds the fuel off the pump and 
> returns it to the tank,  Since the pressure inside the pump can't get 
> high enough to break open the injectors, the fuel seems to be cut off, 
> at least as far as the injectors see it.

A little clarification on the above, the feed pump is still circulating fuel through the pump and returning it to the tank with 
the fuel cutoff solenoid is off.  But looking at the diagram and description at:
	http://www.cs.rochester.edu/u/jag/vw/engine/fi/injpump.html

It seems the solenoid does opens and shut off the fuel channel between the feed pump and the metering pump.
This would prevent fuel from filling the plunger, but there is still likely some residual fuel left in the pump that wasn't 
injected on the previous stroke.  So maybe it is OK to run it for a while w/o feeding fuel into the metering pump.  Never tried 
it myself.

-- 
    Roger