True.
During cruise/light throttle situations you will see the O2 voltage
bounce back and forth between rich and lean.
Alan
'98 Dakota R/T (Headers, FABM & gave up on Shift kit)
'89 Mustang GT (347, Griggs GR-40 , Vortech S-trim...)
Ducati 996 (someday)
-----Original Message-----
From: Bob Tom [mailto:tigers@bserv.com]
Sent: Friday, October 30, 1998 7:23 AM
To: dakota-truck@buffnet.net
Subject: DML: Re: DML: RE: JET opinion * Your
opinion wanted???
Some info. about PCM under WOT.
This applies to the 97 PCM ... can't speak for other
years.
The PCM operates in 2 different modes: Open Loop and
Closed Loop.
During Open Loop modes, the PCM receives inputs and
responds according
to "preset PCM programming". Input for O2S is not
monitored during
Loop Modes.
During Closed Loop modes, PCM monitors O2S input. This
input indicates
to the PCM whether or not the calculated injector pulse
width results
in the ideal air-fuel ratio (14.7 to 1). By monitoring
the exhaust oxygen
content via the O2S, the PCM fine tunes the injector
pulse width.
The fuel injection system has the following modes of
operation:
Open Modes: Ignition switch ON
Engine start-up (crank)
Engine warm-up
Acceleration
Deceleration
WOT <==================ignores O2S and
provides a
predetermined amt
of extra fuel
Ignition switch OFF
Closed Modes: Idle
Cruise
PCM inputs under WOT:
Battery voltage
Crankshaft position sensor
Engine coolant temperature sensor
Intake manifold air temperature sensor
MAP sensor
TPS
Camshaft position sensor signal
Bob
Burlington, Ontario, Canada
tigers@bserv.com
Current: '97 CC Sport, 5.2L, 3,55 auto., Gibson dual,
K&N filter element.
'85 Shelby Turbo Charger, 2.2L, manual.
'70 Challenger, 383-4bbl, auto.
Past: '71 Road Runner, 340-4bbl, auto.
'70 Duster 340, auto.
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