1991 1999 ford explorer chilton User Manual

Exploded view of the EGR system and related components for the 3.0L engine
Click to enlarge
HOW TO USE THIS BOOK
COMPONENT TESTING 527 

Exploded view of the EGR system and related components for the 4.0L engine
Click to enlarge
System Integrity Inspection
Check the EGR system hoses and connections for looseness, pinching, leaks, splitting, blockage, etc. Ensure
that the EGR valve mounting bolts are not loose, or that the flange gasket is not damaged. If the system
appears to be in good shape, proceed to the EGR vacuum test, otherwise repair the damaged components.
EGR System Vacuum Test
The EVR solenoid has a constant internal leak; this...

Apply battery voltage (approximately 1 volts) and a ground to the EVR solenoid electrical terminals.
Attempt to lightly blow air, once again, through the solenoid. If air does not pass through the solenoid, replace the solenoid with a new one.
1. 
If air does not flow through the solenoid, the solenoid is OK.
2. 
3. 
EGR Valve Function Test Install a tachometer on the engine, following the manufacturers instructions.
1. 
Detach the engine wiring harness connector from the Idle Air Control (IAC)...

Detach and label the wiring harness connector from the PFE/DPFE sensor.
2. 
Disconnect all of the hoses from the sensor.
3. 
Remove the mounting nuts, then separate the sensor from the mounting bracket.
4. 
If necessary, remove the EVR solenoid and the PFE/DPFE mounting bracket from the upper intake
manifold.
5. 
To install: If removed, install the EVR solenoid and mounting bracket onto the upper intake manifold.
6. 
If applicable, install the EGR tube heat shield.
7. 
Position the PFE/DPFE sensor on the...

Cutaway view of a base entry type EGR valve
Click to enlarge
Cutaway view of a side entry type EGR valve Click to enlarge
To install: HOW TO USE THIS BOOK
REMOVAL & INSTALLATION 531 

Install the EGR valve, along with a new gasket, on the upper intake manifold, then install and tighten
the mounting bolts to 4-22 ft. lbs. (20-30 Nm) on 3.8L engines, or to 106-49 inch lbs. (1-18 Nm) on
5.0L engines.
8. 
Connect the EGR valve-to-exhaust manifold tube to the valve, then tighten the tube nut to 30 ft. lbs.
(41 Nm).
9. 
Connect all wiring or hoses to the EGR valve.
10. 
Install the air inlet tube.
11. 
Connect the negative battery cable.
12. 
Chilton® Automotive Information Systems. © 2004...

ELECTRONIC ENGINE CONTROLS
Electronic Engine Control (EEC)
All Sequential Fuel Injection (SFI) systems use the EEC system. The heart of the EEC system is a
micro-processor called the Powertrain Control Module (PCM). The PCM receives data from a number of
sensors and other electronic components (switches, relay, etc.). Based on information received and
information programmed in the PCMs memory, it generates output signals to control various relay, solenoids
and other actuators. The PCM in the EEC system...

correct amount of air/fuel ratio throughout the entire engine operational range.
Based on the information that is received and programmed into the PCMs memory, the PCM generates output
signals to control relays, actuators and solenoids. The PCM also sends out a command to the fuel injectors
that meters the appropriate quantity of fuel. The module automatically senses and compensates for any
changes in altitude when driving your vehicle.
REMOVAL & INSTALLATION
Typical PCM module
491-92 Models
Disconnect...

View of the right-hand kick panel PCM mounting for 491-92 models
Click to enlarge
To install: Install the PCM in the mounting bracket.
5. 
Attach the wiring harness connector to the module, then tighten the connector retaining bolt.
6. 
Install the right cowl trim panel.
7. 
Connect the negative battery cable.
8. 
493-99 Models
The module is mounted under the hood on the firewall. On 493-94 models, it is mounted low on the firewall,
near the left-hand fender (drivers side). On 495-99 models, it is...

Exploded view of the firewall PCM mounting for 493-94 models
Click to enlarge
Exploded view of the firewall PCM mounting for 495-99 models Click to enlarge
Disconnect the negative battery cable.
1. 
Disengage the wiring harness connector from the PCM by loosening the connector retaining bolt, then
pulling the connector from the module.
2. 
Remove the two nuts and the PCM cover.
3. 
Remove the PCM from the bracket by pulling the unit outward.
4. 
To install: Install the PCM in the mounting bracket.
5....