1993 CHEVROLET DYNASTY Service Manual

Page 1889 of 2438

CHEVROLET DYNASTY 1993  Service Manual tion timing from the crankshaft position sensor. Once 
crankshaft position has been determined, the PCM
begins energizing the injectors in sequence. The crankshaft position sensor is located in the
tr

Page 1890 of 2438

CHEVROLET DYNASTY 1993  Service Manual SPEED CONTROLÐPCM INPUT
The speed control system provides four separate 
voltages (inputs) to the PCM. The voltages corre-
spond to the On/Off, Set, and Resume. The speed control ON voltage informs t

Page 1891 of 2438

CHEVROLET DYNASTY 1993  Service Manual within a range of 12.9 to 15.0 volts. Refer to Group 
8A for charging system information.
AUTO SHUTDOWN (ASD) RELAY AND FUEL PUMP 
RELAYÐPCM OUTPUT
The PCM operates the auto shutdown (ASD) relay 
and

Page 1892 of 2438

CHEVROLET DYNASTY 1993  Service Manual operator that the PCM has entered a Limp-in mode. 
During Limp-in Mode, the PCM attempts to keep the
system operational. The malfunction indicator signals
the need for immediate service. In limp-in mo

Page 1893 of 2438

CHEVROLET DYNASTY 1993  Service Manual the PCM determines crankshaft position, it begins 
energizing the injectors in sequence.The auto shutdown (ASD) relay supplies battery
voltage to the injectors. The PCM provides the
ground path for th

Page 1894 of 2438

CHEVROLET DYNASTY 1993  Service Manual IGNITION SWITCH ON (ZERO RPM) MODE When the multi-port fuel injection system is acti- 
vated by the ignition switch, the following actions oc-
cur:
²  The PCM determines atmospheric air pressure 
fro

Page 1895 of 2438

CHEVROLET DYNASTY 1993  Service Manual WIDE OPEN THROTTLE MODE This is an OPEN LOOP mode. During wide-open- 
throttle operation, the following inputs are received
by the PCM:
²  battery voltage 
²  engine coolant temperature 
²  manifol

Page 1896 of 2438

CHEVROLET DYNASTY 1993  Service Manual FUEL PRESSURE REGULATOR
The pressure regulator is a mechanical device lo- 
cated on the fuel rail, downstream of the fuel injec-
tors (Fig. 21). The regulator maintains a constant
330 kPa (48 psi) acr