FBC System Inspection (Ram 50)
INSPECTION OF FBC SYSTEMIf FBC system components (sensors, carburetor control unit - computer, solenoid, etc.) fail, interruption of fuel supply or failure to supply proper amount of fuel for engine operating conditions will result. Therefore, the following situations will be encountered.
(1) Engine is hard to start or does not start at all.
(2) Unstable idle.
(3) Poor driveability.
If any of above conditions is noted, first perform basic engine checks (ignition system malfunctions, incorrect engine adjustment, etc.). the FBC system can be checked by use of voltmeter. Inspection procedure as follows.
Inspection Procedure
FIGURE 24 - CARBURETOR CONTROL UNIT:
With the voltmeter, use the diagram on pages 19 and 20 (Fig. 24) to identify the pin connectors (terminals). Check the voltage of each terminal as specified in the "Output Signals from Tester". Make sure the ignition switch, vehicle operation and conditions are observed as called out in the procedure.
Output Signals from Tester
1985 D-50 Publication #81-370-5015 Revision 6-2-86
FIGURE 24 - CARBURETOR CONTROL UNIT:
Carburetor Control Unit
If carburetor control unit appears defective, all tests and individual sensor tests. If everything is in order, replace the carburetor control unit.
Connector A
(1) Oxygen sensor
(2) Ground for sensor
(3) Power supply for sensor
(4) Intake air temperature sensor
(5) Vacuum switch
(6) Ground
(7) Ignition switch
(8) Ignition switch
(9) Battery
(10) Ignition coil negative terminal
(11) Ground
(12) Coolant temperature sensor
(13) TPS output
Connector B
(1) Jet mixture solenoid valve
(2) Deceleration solenoid valve
(3) Throttle opener control solenoid valve
(4) Secondary air control solenoid valve
(5) Enrichment solenoid valve
(6) Air-Con. cut solenoid
(7) Ignition timing advance vacuum exchange solenoid valve
1985 D-50 Publication #81-370-5015 - Revision 6-2-86