Engine Controls - Tests W/o Codes - Eec-Iv: Diagnosis Lincoln Mark I

SYMPTOMS DIAGNOSIS

Symptom checks cannot be used properly unless problem occurs while vehicle is being tested. To reduce diagnostic time, ensure steps in appropriate BASIC TESTING and TESTS W/CODES articles in the ENGINE PERFORMANCE Section were performed before diagnosing a symptom.

Use diagnostic charts to identify systems and components that should be checked for fault. See DIAGNOSTIC CHART INDEX . Perform check or adjustment procedure indicated in appropriate diagnostic chart.

DIAGNOSTIC CHART INDEX

INTERMITTENT PROBLEM DIAGNOSIS

Intermittent fault testing requires duplicating circuit or component failure to identify the problem. These procedures may lead to the computer setting a fault code (on some systems), which may help in diagnosis.

If problem vehicle does not produce fault codes, monitor voltage or resistance using a DVOM while attempting to reproduce conditions causing intermittent fault. A status change on DVOM indicates a fault has been located.

Use a DVOM to pinpoint faults. When monitoring voltage, ensure ignition switch is in ON position or engine is running. Ensure ignition switch is in OFF position or negative battery cable is disconnected when monitoring circuit resistance. Status changes on DVOM during test procedures indicate area of fault.

Continuous Monitor Mode (WIGGLE TEST)

In this mode, the technician can attempt to re-create an intermittent fault while monitoring the system. This mode, also called the WIGGLE TEST, may be used in Key On Engine Off (KOEO) and Key On Engine Running (KOER) self-test modes. See CIRCUIT TESTS in TESTS W/CODES article in the ENGINE PERFORMANCE Section for instructions on the use of this procedure to identify intermittent faults in specific circuits or components.

KOEO WIGGLE TEST Procedure

Connect test equipment. See TESTS W/CODES article in the ENGINE PERFORMANCE Section. Turn ignition on. Activate self-test using jumper lead or diagnostic tester. Wait 10 seconds, and then deactivate and reactivate self-test to enter WIGGLE TEST. Tap, move and wiggle the suspected sensor and/or harness area. If a fault is detected, a code may be stored in memory and indicated at the diagnostic tester or Scan tool. Record or retrieve code, and perform CIRCUIT TEST indicated in TESTS W/CODES article in the ENGINE PERFORMANCE Section.

KOER WIGGLE TEST Procedure

Connect test equipment. See TESTS W/CODES article in the ENGINE PERFORMANCE Section. Turn ignition off, and wait 10 seconds. Start engine. Activate self-test using jumper lead or diagnostic tester. Wait 10 seconds, and then deactivate and reactivate self-test to enter WIGGLE TEST. DO NOT turn engine off. Tap, move and wiggle the suspected sensor and/or harness area. If a fault is detected, a code may be stored in memory and indicated at the diagnostic tester or Scan tool. Record or retrieve code, and perform CIRCUIT TEST indicated in TESTS W/CODES article in the ENGINE PERFORMANCE Section.

DIAGNOSTIC CHARTS

Note. For SYSTEM & COMPONENT TESTING references, see I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.

CHART 16-STATE EMISSION TEST FAILURE

Note. Canada and some states or metropolitan areas in the United States require periodic idle emission tests. All Ford products have been designed to pass these tests. If a Ford product fails an idle Emission test, it is probable that 1), the engine temperature was not warm and stabilized prior to the test, or 2), the vehicle had idled excessively long prior to the test.

Before starting any services, verify complaints of idle emission test failure by using test procedure of area that failed vehicle.

The following encompasses most of the emissions measurement modes of current state idle test procedures

1. Ensure engine is at normal operating temperature and all accessories are turned off.
2. Read emissions at idle.
3. Operate engine at 2200-2800 RPM.
4. Read emissions within 30 seconds.
5. Return engine speed to idle.
6. Read emissions within 30 seconds.

If any emission component is changed, Keep-Alive Memory (KAM) should be cleared before repeating state emission test procedure. See TESTS W/CODES article in the ENGINE PERFORMANCE Section.

DIAGNOSTIC CHART 16-STATE EMISSION TEST FAILURE