Shane,
The DRB-III showed a 2003 model going into closed loop at right about 2
minutes. I verified this with our Master Tech (20 years experience on
these vehicles) and he did state that yes...the variable was changed
from 160 to 140 degrees (ECT) in 2001 for one of the factors determining
Closed Loop. O2 sensors also come into play, but ECT is a main factor.
(You can compare it to the choke on the old carbureted vehicles.)
I can try to save some data files (or printouts) for you if you like.
I've got access to most anything from the late 80's to current (NGC).
- Bernd
-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Shane
Moseley
Sent: Monday, August 25, 2003 8:48 PM
To: dakota-truck@dakota-truck.net
Subject: Re: DML: injectors (Ron)
As some will remember, my results differ from these - I don't believe
that closed loop is determined by temperature. My opinion is that the
onset of closed loop is determined by the oxygen sensor being at a state
where reliable readings can be made. I make this assertion after doing
some testing when I used to live in the mountains around Nashville, TN.
With my scan tool connected and reading all variables in real-time, I
cranked my truck up and went to work at least a hundred times with the
scantool logging everything. From this data I learned that when the
oxygen sensor crossed the 0.45 volt threshold for the first time (or was
it second, can't remember exactly) this marked the point when the system
would transition from open loop to closed loop during a cold start. The
data showed that it didn't have anything to do with temperature. I sat
many times in my driveway in 0-15 degree weather watching the system go
into closed loop with the ECT still in the "below 100" degree range. In
fact, on a cold start (any weather condition) by looking at NOTHING but
an A/F gauge I can tell you exactly (within +- 1 second) when it will go
into closed loop. Try that with temperature. Someone with a scantool
in a cold area needs to check this out and report their findings.
Peace!
Shane
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