DFI, Batch Fire, and other myths

[Shannen Durphey]

GM is hard to figure out.  The 2.8l and some 3.1l v-6 engines used a
double batch fire
arrangement, even though there was only one O2 sensor,.  Then, the
Vortech 4.3 used a single injector with 6 nozzles firing
simultaneously, and I think the Vortech smallblock is the same. 
However, the 7.4l vortech has 8 injectors and IIRC is sequential. 
I'll bet the 88,89 vintage Caddies were not single batch fire, though.
Nor were the 86 GN's. Then they go to extra lengths to redesign a
transfer case for a magnesium case because it's 8lbs lighter than
aluminum.  Ya just gotta wonder sometimes.
Shannen

diy_efi at efi332.eng.ohio-state.edu wrote:
> 
> On Wed, 20 Jan 1999 thergen at svn.net wrote:
> 
> > Does your '93 Z28 also have two O2 sensors?  This would make sense with
> > two separate timers controlling separate drivers.
> >
> > Tom
> >
> Yes it does.  And I guess that would make sense, with one O2 sensor
> what is the point of not firing them all the same (8 at once).   The
> 93 has an O2 sensor for each bank so fires 4 at a time.
> 
>                                 Roger