Ford Festiva. Instruction — part 68

Fig. 16: Cutaway View Of Typical Integrated Electronic EGR Valve

Courtesy of GENERAL MOTORS CORP.

SPARK CONTROLS (SPK)

Spark control systems are designed to ensure the air/fuel mixture is ignited at the best possible moment to provide optimum efficiency and
power and cleaner emissions.

Ensure vacuum hoses to the distributor, carburetor, spark delay valves, thermal vacuum switches, etc., are in place and routed properly. On
Computerized Engine Controls (CEC), check for presence of required sensors (O2, MAP, CTS, TPS, etc.). Ensure they have not been
tampered with or modified.

Check for visible modification or replacement of the feedback carburetor, fuel injection unit or injector(s) with a non-feedback carburetor or
fuel injection system. Check for modified emission-related components unacceptable for use on pollution-controlled vehicles.

AIR INJECTION SYSTEM (AIS)

Air Pump Injection System (AP)

The air pump is a belt-driven vane type pump, mounted to engine in combination with other accessories. The air pump itself consists of the
pump housing, an inner air cavity, a rotor and a vane assembly. As the vanes turn in the housing, filtered air is drawn in through the intake port
and pushed out through the exhaust port. See

Fig. 17

Check for missing or disconnected belt, check valve(s), diverter valve(s), air distribution manifolds, etc. Check air injection system for proper
hose routing.

Fig. 17: Typical Air Pump Injection System

Courtesy of GENERAL MOTORS CORP.

Pulsed Secondary Air Injection (PAIR) System

PAIR eliminates the need for an air pump and most of the associated hardware. Most systems consists of air delivery pipe(s), pulse valve(s) and
check valve(s). The check valve prevents exhaust gases from entering the air injection system. See

Fig. 18

Ensure required check valve(s), diverter valve(s), air distribution manifolds, etc., are present. Check air injection system for proper hose
routing.

Fig. 18: Typical Pulsed Secondary Air Injection System

Courtesy of GENERAL MOTORS CORP.

OXYGEN SENSOR (O2)

The O2 sensor is mounted in the exhaust system where it monitors oxygen content of exhaust gases. Some vehicles may use 2 O2 sensors. The
O2 sensor produces a voltage signal which is proportional to exhaust gas oxygen concentration (0-3%) compared to outside oxygen (20-21%).
This voltage signal is low (about .1 volt) when a lean mixture is present and high (1.0 volt) when a rich mixture is present.

As ECM compensates for a lean or rich condition, this voltage signal constantly fluctuates between high and low, crossing a reference voltage
supplied by the ECM on the O2 signal line. This is referred to as cross counts. A problem in the O2 sensor circuit should set a related trouble
code.

COMPUTERIZED ENGINE CONTROLS (CEC)

The CEC system monitors and controls a variety of engine/vehicle functions. The CEC system is primarily an emission control system designed
to maintain a 14.7:1 air/fuel ratio under most operating conditions. When the ideal air/fuel ratio is maintained, the catalytic converter can
control oxides of nitrogen (NOx), hydrocarbon (HC) and carbon monoxide (CO) emissions.

The CEC system consists of the following sub-systems: Electronic Control Module (ECM), input devices (sensors and switches) and output
signals.

EARLY FUEL EVAPORATION (EFE)

The EFE valve is actuated by either a vacuum actuator or a bimetal spring (heat-riser type). The EFE valve is closed when engine is cold. The
closed valve restricts exhaust gas flow from the exhaust manifold. This forces part of the exhaust gas to flow up through a passage below the

carburetor. As the exhaust gas quickly warms the intake mixture, distribution is improved. This results in better cold engine driveability,
shorter choke periods and lower emissions.

Ensure EFE valve in exhaust manifold is not frozen or rusted in a fixed position. On vacuum-actuated EFE system, check EFE thermal vacuum
valve and check valve(s). Also check for proper vacuum hose routing. See

Fig. 19

Fig. 19: Typical Vacuum-Actuated EFE System

Courtesy of GENERAL MOTORS CORP.

EMISSION MAINTENANCE REMINDER LIGHT (EMR)

If equipped, the EMR light (some models may use a reminder flag) reminds vehicle operator that an emission system maintenance is required.
This indicator is activated after a predetermined time/mileage.

When performing a smog check inspection, ensure EMR indicator is not activated. On models using an EMR light, light should glow when
ignition switch is turned to ON position and should turn off when engine is running.

If an EMR flag is present or an EMR light stays on with engine running, fail vehicle and service or replace applicable emission-related
components. To reset an EMR indicator, refer to appropriate MAINTENANCE REMINDER LIGHTS article in GENERAL INFORMATION.

MALFUNCTION INDICATOR LIGHT (MIL)

The Malfunction Indicator Light (MIL) is used to alert vehicle operator that the computerized engine control system has detected a
malfunction (when it stays on all the time with engine running). On some models, the MIL may also be used to display trouble codes.

As a bulb and system check, malfunction indicator light will glow when ignition switch is turned to ON position and engine is not running.
When engine is started, light should go out.

Article GUID: A00130226

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GENERAL INFORMATION

Engine Performance Diagnostic Routine Outline

* PLEASE READ THIS FIRST *

WHERE DOES DRIVEABILITY DIAGNOSIS START?

PERFORM BASIC INSPECTION

1. Verify Customer Complaint
2. Perform Visual Inspection (See Basic Diagnostic Procedures)
3. Test Engine Sub-Systems (See Basic Diagnostic Procedures)



Mechanical Condition (Compression)



Ignition Output



Fuel Delivery

4. Check Air Induction System For Leaks
5. Check & Adjust Basic Engine Settings(See On-Vehicle Adjustments)



Ignition Timing



Idle Speed

CHECK FOR TROUBLE CODES

1. Check for Diagnostic Trouble Codes (DTCs).(See Self-Diagnostics)
2. Repair cause of DTCs.
3. Clear PCM memory and repeat self-test.

DIAGNOSE SYMPTOM

1. If no self-diagnostics available, or no trouble codes present, identify symptom.
2. See trouble shooting procedure to identify problem. (See Trouble Shooting - No Codes)

TEST SYSTEM

1. Perform required tests. (See Systems & Component Testing)
2. Verify complaint is repaired.

NOTE: