Re: RS2 Injectors & fault code

[DeWitt Harrison <de@aztek-eng.com>]

On Thu, 28 Jan 1999 13:17:00 -0800, Frank Amoroso wrote:
>[ ... ]
>My injectors are, in fact, maxed out at high boost so added pressure 
>wouldn't do me any good, correct?
>Another question, on increased fuel pressure. I used to have a rising rate 
>fuel pressure regulator on the car but I was told that on a closed loop 
>system the computer will counteract / compensate for the increased pressure 
>by closing the injector sooner. Thus making the rising rate fuel pressure 
>regulator counter productive or at least nullifying its claimed benefit and 
>making it an expensive way to stress out your fuel pump. Agree or dis-agree?
>[ ... ]

For a given duty cycle, for example 100%, the injectors will deliver more
fuel with higher fuel pressure. If you've run out of headroom on the injectors,
higher fuel pressure will help; the rising rate regulator is probably a good
thing in your system, effectively increasing the "dynamic range" of the system.
Of course, there is a possibility of leaning out due to saturation of the
air mass
flow thingy.

With regard to your stumble at WOT, another thing to consider is that at
absurdly high boost levels you are running (3 bar total pressure was it?), in
combination with the low air density at high altitude (you were speaking about
WOT uphill at 10,000 ft., correct?) you may be demanding the turbo run at
a pressure ratio in excess of its capacity and pushing it over the surge line.
The Motronic system does correct for altitude I assume but I wonder if it
can correct enough with your current ECU firmware.

DeWitt Harrison
Boulder, CO
88 5kcstq