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
Bernd D. Ratsch wrote:
>2001 models will go into Closed Loop at 140 (not 160 like the older
>models)...that's the difference (about 2 minutes instead of 2.5-3
>minutes from cold-startup).
>
>- Bernd
>
>-----Original Message-----
>From: owner-dakota-truck@bent.twistedbits.net
>[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Bob Mankin
>Sent: Thursday, August 21, 2003 6:15 PM
>To: dakota-truck@dakota-truck.net
>Subject: RE: DML: injectors
>
>
>Ron, the '01 and later stuff idles in closed loop. Another little known
>twist. That's why it handles the bigger injectors better than the older
>controllers.
>
>Bob
>
>
>
>
>
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