[Vwdiesel] Why gasss cars mpg sucks (fwd)

[Val Christian]

> I wonder if this is how it is done in the TDIs. It would seem to be a fairly simple thing 
> to design, perhaps using the dynamic oil pressure circuit which triggers at 2000rpm, 
> or just working off the tach signal. But I wonder if prolonged fuel cutoff at highway 
> speeds could cause fuel starvation in the pump, ie: lack of lubrication? I don't know if 
> the location of the solenoid poses a problem in this way or not...

I haven't throughly investigated this, but I believe that the shutoff is
electrical, in that there is a command to inject zero fuel.  Exactly how 
that is accomplished by the IP I haven't dug into.  I can tell you that 
driving hills in the winter can cause the engine to get REAL cold real 
fast.  That much I've observed.  Oh, and the zero fuel injected happens 
well below 2000 RPM.  I have seen it in the 1000 to 1200 range.  It may 
happen lower, I just haven't checked.  

Val