At 11:31 AM 8/24/99 -0700, you wrote:
>So, what's up with the computer in the Dak's that makes them different than
>other vehicles. I still haven't gotten an answer to my question about the
>fuel map for the ECU. If someone out there knows I'd really like an answer
>as to whether or not the Dakota computer runs in open loop during full
>throttle settings. [snip]
Here's a statement that I came across and was surprised at the last sentence
in the response as I had heard basically the opposite from the DML.
[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?
[Response from a DC s/w 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.
Bob
Burlington, Ontario
'97 CC Sport, 5.2L, 3.55, auto., 4x2, flame red
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:16:02 EDT