ION and EGOR

[Shannen Durphey]

Although I cannot say that GM does not use seperate mixture
control per bank, the main reason there are 4 sensors on
some OBDII vehicles is to measure converter effectiveness. 
These vehicles use exhaust configurations which place the
converters before the Y pipe, and therefore need pre- and
post-cat sensors on both banks to satisfy the EPA.

Shannen
kenkelly at lucent.com wrote:
> 
> you don't have to look offshore. the 96 Chevy LT-1 in Camaro, firebird, and
> corvette uses 1 primary & one aftercat O2 sensor per exhaust manifold. I think
> they run seperate mixture control on each bank. It is a sequential injection
> with a seperate injector pulse for each cylinder.
> 
>                 Ken
> 
> Bruce Plecan wrote:
> >
> > Subject: RE: ION and EGOR
> >
> > >> Gotcha covered again. Good point on the multiple
> > >> sensor business. BTW,
> > >> do any production cars ever come this way with duals
> > >> on exh and sensor?
> > >> Just wonderin if there are stock ECMs available to
> > >> scan two sensors.
> > >> Heh, not sure what they'd do, control mix on each bank
> > >> separate (:o) or
> > >> what, but it's an interesting question.
> > >
> > >  Not a per-bank thingus (IIRC), but the Nissan 300ZX has 2 EGO's:
> > >1 Before Cat & 1 After Cat.  I dunno what they are supposed to do
> > >(cept maybe tell the mechanic that you bypassed the cat!)
> > >
> > >-Thor Johnson
> > >thormj at iname.com
> > >
> > Might look at a ZR-1 vette, I think it had a dual O2 for per bank
> > monitoring, but that might have been for misfires rather than
> > mixture.  McClaren F1 street car has dual bank monitoring as
> > I recall, but probably 4 O2's.


> > Bruce