Horrible running 8v

[jdbubb at ix.netcom.com (Dan Bubb)]

> > Jason Peters wrote:
> >
> > > Hello everybody,
> > >
> > > I'm pretty new to the 'rocco list so excuse me if this is an easy
> > > question/fix.  First a little background: '83 'rocco 8v on CIS
> > >
> > > I replaced the O2 sensor with a nice new one, connected it and fired
> > > it up.  Seemed to run fine for the first few minutes(maybe till the
> > > sensor warmed up) after that the idle started to hunt around up and
> > > down.  Backed out of the drive way and the car would barely go.
> >
> > Welcome!
> >
> > 1. Those one-wire sensors only warm up from exhaust heat.  Three-wire
> > sensors have a heater in 'em. Ones would perform worse when cold if
> > everything else is good.
> >
>
> Not so...  The ECM does not use the signal from the O2 until after warm-up.  BTW, the only reason
> there is a heater in the 02 is so that it will be a cleaner-burning engine, purely for emissions
> standards...

Actually, the heater is there for quicker warmup so the engine can go closed loop sooner (for
emissions) and also to keep the O2 sensor hot in situations where the exhaust heat is inadequate. An
example being the 16V sensor that is far away from the engine during extended idling. (again, I
suppose, just for emissions)

>  A properly tuned CIS system will run fine, all the time...

Yes, an 8V should run fine all the time with or without the O2 sensor if properly tuned.

>  I think you have fuel pressure
> problems, more than likely from the warm-up regulator mounted on
 > you block.  You won't know that until you check the control and
> system pressures both hot and cold...
>
> My .02,
>    David
>
>
> ---Chrome don't get you home.---
>
>
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