EFI questions

[Shannen Durphey]

dzorde wrote:
> 
<snip>
> Another question, because the system is speed density, when you back of the
> accelerator the engine unloads and picks fuel delivery for its new suited
> map point (lower load range) causing the O2 to read almost 0V (very lean).
> Is this normal for a speed density system ?  It seems correct to me as the
> injection is based on looking up a base value in the map, but it doesn't
> seem very healthy for the engine to lean of everytime you back of.  I have
> been thinking this could be why I have white tailpipes as the car is
> spending most of its time on and off the gas when racing.
> 
> Lots of questions, but this one has me puzzled.
> 
> rgds
> 
> Dan     dzorde at soanar.com.au
GM stuff leans out during decel and high rpm/no load.  It's not as
noticeable in the gas stuff, but the EFI diesels actually seem to shut
down during decel.  It's one way to help fuel economy.
Shannen