Fuel injection questions

[Phil@sievers.com (Phil Payne)]

In message <199704201656.JAA20188@gonzo.wolfenet.com> orin@WOLFENET.com writes:

> > a) I used the on-board diagnostics to run the fuel pump and warm-up valve.
> > Then I applied vacuum to the pressure regulator.  The fuel pump noise
> > rose in pitch, quite noticably.
>
> Careful doing tests running the fuel pump by on-board diagnostics - there
> is some funny code in the MAC11 computer at least - I think it cycles
> the power to the fuel pump at a 50% duty cycle.

Not on the MAC12.  The pump is powered via the relay, and the relay is
held hard over.

> > A bigger surprise came when I measured system pressure.  I had hypothesised
> > that the two were brought under one valve's control on the MB to allow system
> > pressure to be increased as control pressure is decreased as a result of the
> > vacuum input.  WRONG!  System pressure drops almost 1.0 bar with 0.5 bar of
> > vacuum input.
>
> Ah, but what happens when you apply pressure to it?  One would expect an
> increase in system pressure in this case.

It never sees pressure in operation - it's hooked to the air mass sensor
plenum chamber.

> BTW, for us US types, what is the spec for HP and max boost for your car?

200bhp stock.  Maximum boost is something like 7 or 8 psi.  I'll check
and post a note later.

--
 Phil Payne
 Phone: +44 385302803  Fax: +44 1536723021  CIS: 100012,1660