I thought that the following information would give some insight
into the computer situation involving our trucks. Keep in mind
that this information is from the eGroup R/T Owner Mailing
List and, thus, some may be specific to the R/Ts only. I joined
the eGroup so I could monitor the list and have another source for
performance issues but the moderator of the R/T Owner Mailing list
denied me membership so I cannot ask questions nor can I participate
in their discussions. I have many questions for this engineer relating
to all Dakotas but I do not feel that it is proper for me to privately
use his email address. Although he is a DC s/w engineer, he is, first
and foremost, an R/T owner.
[DC engineer on computer situation in general]
Software for these computers involves many people in two main areas of
expertise. One area writes the algorithms on how things are to function.
The other area works on what is called calibrations. These are the values
that the programs used to operate the engine. These calibrations would
include,
for example, fuel injector pulse width, ignition advance, cold start fuel
priming,
etc. All which affect fuel emissions. With so many government regulations,
the software groups are so busy keeping up with new restrictions that playing
around with performance calibrations has been severly restricted. That's why
everybody, including the aftermarket, is "coming out with one" but can't
quite do it.
[R/T owner question]
Someone recently wrote to the group with a difference in the computers
from a 98 to a 99. What, if the computer chip is, is the difference?
[DC engineer]
Complete controller is different, not just memory chip. Complete software
program is also different. Software and hardware are not interchangeable.
Some input/output sensor controls are different. Externally they look
the same, but are nowhere close inside.
[R/T owner question]
If this is the case, then sign me up for the purchase of a 98 computer.
I think that if I get that my performance will increase.
[DC engineer]
No, truck probably would do worse since I/O control is wrong and some
default computer values would be used instead of actual "real reading" values.
[R/T owner question]
I think that someone wrote that the 99 computers have a 16 bit memory
chip or learning chip....something like that, anyways, the 98's don't have
such a thing.
[DC engineer]
Yes, the '99 is a 16-bit based controller and the '98 is an 8-bit based
controller. They both have learning algorithms in software. This
allows the truck to learn your driving habits and adapt accordingly.
[R/T owner question]
I have a quick question about WOT on the R/T. Does the computer
"learn" anything when it is at WOT (open loop)? That is to say... can
my WOT settings be different than say, someone else's R/T due to my
driving habits? Or is this a part throttle closed loop situation only?
[DC engineer]
Conceiveably everybody could have different WOT end points (highest and
lowest voltage values learned by their computer). However, when
components are designed, upper and lower limits are set and a mean is
established. This mean (or average value) is normally maintained by the
sensor supplier so that most sensors produced are almost identical.
When you talk about open loop, I am assuming you understand that that
means that some external sensors inputs are ignored until valid data is
available. Most of these are for fuel emissions controls. That is why
manufacturers now use heated oxygen sensors. Oxygen sensors only
provide useful data once they are "warmed up". The old way was for the
exhaust pipe to heat up and then, in turn, heat up the oxygen sensor.
Now with heated sensors, an internal heating element heats the sensor
way before the exhaust pipe is hot. This now allows for closed loop
operation sooner. So a long story, trying to stay short, WOT does not
determine closed vs open loop that much.
[R/T owner question]
Also one more question... what do you think about the 98s being quicker
than the 99s due to the new computer? Shouldn't they be the same if
they have the same horsepower and torque levels?
[DC engineer]
Yes and No...
Performance differences have always been the case. Even though the
engine H/W (hardware/engine mechanicals) are the same, the more "smog"
restrictions/controls you put on them, the more performance is
degraded. That's also why "stock" California S/W (software) programmed
vehicles are slower than Federal S/W programmed "stock" ones. However,
that's changing as well, future "new development" engine packages have
the same restrictions for both Federal and California. The hardware
in the controller is different, as discussed previously, and the
software is different. Guess what, you got it, more restrictions/controls
added.
Anybody ever wonder how the performance numbers of the old muscle cars slowly
dwindled away. It wasn't just the manufacturers trying to reduce hp numbers
for cheaper vehicle insurance. Surely you guys didn't believe that story.
There was this big thing called an oil crisis, which seemed to get the
government
involved and mandate better economy figures.
It's a damn shame that we've got all these lists going ...
Bob
Burlington, Ontario
'97 CC Sport, 5.2L, 3.55, auto., 4x2, flame red
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