RE: Re: RE: JET opinion * Your opinion wanted???

From: Mok, Alan (AMok@spbank.com)
Date: Fri Oct 30 1998 - 17:11:40 EST


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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