no codes are being set, ie, neither check engine light is on.
i am aware of the OBD-I and OBD-II but are you saying that
an OBD scan device will tell me continuous info about fuel
trim, etc?
On Apr 20, 9:52=A0pm, al <abuo...@[EMAIL PROTECTED]
> wrote:
> On Apr 20, 7:24=A0am, nucleus <rose122...@[EMAIL PROTECTED]
> wrote:
>
>
>
>
>
> > thanks al, plugs look identical, temp guage on both are in approximate
> > same position when at operating temp.
>
> > what kind of "scan tool" is this that will measure fuel trim and
> > ox sensor operation?
>
> > about gas mileage, for 2 years the 94 averages 33.3 mpg and the 96
> > averages 37.7 mpg; long trips are driven at 65 mph max, short highway
> > trips are driven at 55 mph max.
>
> > On Apr 19, 8:05=A0pm, al <abuo...@[EMAIL PROTECTED]
> wrote:
>
> > > On Apr 19, 7:44=A0pm, nucleus <rose122...@[EMAIL PROTECTED]
> wrote:
>
> > > > have been driving a 94 and 96 nissan sentra for several years.
=A0TH=
E
> > > > 96 CONSISTENTLY AVERAGES OVER 4 MPG GREATER THAT THE 94.
>
> > > > both are stock cars, 4 door, 1.6 liter engines, 4 speed/overdrive
au=
to
> > > > transmissions, have same brand & size tires and use the same tire
> > > > pressures, which are adjusted monthly. both cars have almost
identic=
al
> > > > total mileage. =A0no dragging brakes.
>
> > > > the 96 has a different shaped body and is presumably more
> > > > aerodynamically
> > > > efficient. =A0however, both autos are driven in the same city &
high=
way
> > > > mileage
> > > > conditions. =A0the 96 gets better mileage in city driving, than
does=
the
> > > > 94.
>
> > > > is there some sensor, that DOES NOT set a computer code, that can
> > > > cause
> > > > the computer to run the 94 engine richer than the 96 engine?
>
> > > Do the plugs look different between the two cars? =A0If one is
really
> > > runner richer the plugs on that one might show more carbon deposits.
> > > I presume the thermostat is working well on both and is the same
> > > design temperature. =A0Beyond that, if you really want to track it
dow=
n
> > > you can start by putting a scan tool on it and observing the fuel
trim=
> > > and the oxygen sensor behavior. =A0Good luck. =A0Al- Hide quoted
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> > - Show quoted text -
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> Seems unlikely but I suppose with virtually everything else being
> eliminated, you have to consider the odometer calibration may be
> different. =A0I presume both vehicles use the same type of oil also.
> Post 1996 vehicles sold in the US must have an OBD-II diagnostic
> system to monitor pollution related parameters such as fuel trim,
> sensors etc. =A0When something is out of spec, the check engine light
> comes on and a code is set. =A0But all of that data is available for
> viewing with a special purpose piece of diagnostic equipment known as
> a scan tool that plugs into a data ****t that all OBD-II equipped cars
> have just under the dashboard on the driver's side. =A0Pre-1996 cars had
> OBD-I systems so I'm not sure what diagnostic system you've got on
> each car. =A0With all the obvious things eliminated, seems like the next
> way to pursue this is through analyzing the engine data stream.
> That's a whole other level of complexity. =A0Good luck. =A0Al- Hide
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