Any chance the truck sits more than its driven? Or just driven short
distances? If so, could just be a low battery....sucked down over time by
all the electronics. If you throw a volt meter across the terminals and it
reads 12.4 volts or more before starting it then its probably something
else.
Ray
> -----Original Message-----
> From: owner-dakota-truck@bent.twistedbits.net [mailto:owner-dakota-
> truck@bent.twistedbits.net] On Behalf Of John Dunlap
> Sent: Wednesday, September 24, 2008 9:35 AM
> To: dakota-truck@dakota-truck.net
> Subject: Re: DML: RE: RE: Cold engine puts out more hp/tq...
>
>
> Hi,
> While I have a 98 5.2L and it struggles a bit in AM when I first start
> to drive then evens out in about 3 min or so, would that be MAP or air
> temp sensor creating that delay. Some malfunction of something. Also,
> is there a published list on line of code readouts?
> This is just a minor annoyance but if something is failing I don't
> want it to get any worse.
>
> Thanks guys. It really helps to read your communiques. My son started
> me on this site after I got my 98, he was running 02 Durango pretty
> tricked out, used to love to ride in it but nevertheless it was sold
> for a profit, so . . . .
>
>
>
> On Tue, Sep 23, 2008 at 4:30 PM, Phillip Batson <pbatson68@yahoo.com>
> wrote:
> >
> > Wow, great info! I kind of figured it would be something like that.
> Thanks Bernd!
> >
> >
> >
> > ----- Original Message ----
> > From: Bernd D. Ratsch <bernd@dodgetrucks.org>
> > To: dakota-truck@dakota-truck.net
> > Sent: Saturday, September 20, 2008 11:42:44 AM
> > Subject: DML: RE: RE: Cold engine puts out more hp/tq...
> >
> >
> > The sensor signals are put into the PCM which calculates it and compares
> > them to reference values (expected values). If they're within normal
> range
> > (throttle position, MAP, vehicle speed, for example)...the calculation
> runs
> > as posted. On the newer vehicles (starting in 2002), the PCM can insert
> > it's own values if a sensor if out of range. Example: Disconnect the
> Crank
> > sensor on an '05 Dakota and it still starts and runs - the MIL is
> tripped
> > but the PCM inserts its own value to get you down the road to a shop for
> > repair. The ETC engines can also run without the MAP and Crank sensor
> > installed.
> >
> > On the '07+ 3.7/4.7/5.7L engines, you can try to "tune" the PCM with a
> > piggy-back system but you'll never get it right. The PCM only looks at
> the
> > MAP sensor for initial BARO reading - once that's done...it works off of
> > internal, calculated values.
> >
> > In the 1992 case, they're not that elaborate but expected values are
> still
> > in place. Modifying something like the IAT can't affect mileage that
> much
> > since there's a 33% Fuel Trim allowance. The PCM will try to get a
> close to
> > "0" by calculating the difference in between the LTFT and STFT. This is
> why
> > modifying an IAT sensor really doesn't do a whole lot to mileage unless
> you
> > go way out of the normal/expected range.
> >
> > On the fuel adaptives...there are 26 different tables which correspond
> to
> > MAP and Engine Speed. All of them use calculation formula.
> >
> > - Bernd
> >
> >
> > -----Original Message-----
> > From: Phillip Batson [mailto:pbatson68@yahoo.com]
> > Sent: Saturday, September 20, 2008 11:12 AM
> > To: dakota-truck@dakota-truck.net
> > Subject: DML: RE: Cold engine puts out more hp/tq...
> >
> >
> > Are any of those variables calculated or are they all readings from
> sensors
> > on the truck?
> > Another way to ask this is, does the computer just take sensor readings
> and
> > plug them in for the calculation, or does it have something like
> reference
> > tables in its programming to calculate certain values that may exceed
> > certain limits? So, if it gets a reading for say, upstream 02, and it
> is
> > outside some set range, does it modify what it plugs into the equation?
> >
> > If so, that would really limit the 'effect' any one variable has on the
> > equation if there are limits setup for different (or maybe all)
> variables.
> >
> >
> >
> > ----- Original Message ----
> > From: Bernd D. Ratsch <bernd@dodgetrucks.org>
> > To: dakota-truck@dakota-truck.net
> > Sent: Friday, September 19, 2008 8:58:52 AM
> > Subject: DML: RE: RE: RE: RE: RE: RE: Cold engine puts out more hp/tq...
> >
> >
> > Yup...while yes it can, it depends on quite a few other conditions - not
> > just intake air temp.
> >
> > (RPM/Max RPM) x (MAP Baro) x (TPS x ECT x IAT x Sensed Battery Voltage x
> > LTFT) x (Upstream O2) x (STFT x LTFT) = PW
> >
> > That's the formula. The ignition timing is also affected by IAT (but
> not
> > just by itself) so engine and weather conditions do apply. Higher/Lower
> > pressure, engine coolant temp, engine rpm, battery voltage, throttle
> > position...so you're trying to tell me that they don't matter??? What
> about
> > what the O2's read - think about those variables and how the PCM reacts
> too.
> > Fuel mileage is dependent on a lot of variables - yes...the difference
> in
> > between a 30 degree outside ambient and 90 degree outside ambient will
> > affect mileage slightly, but again...pcm calculations need to be figured
> > out.
> >
> > - Bernd
> >
> >
This archive was generated by hypermail 2b29 : Wed Oct 01 2008 - 00:13:23 EDT