Ignition Pinpoint Tests - Service Tips

91ford28

Article No.
91-24-7

11/27/91


IGNITION SYSTEM - 1.9 SEFI, 2.3L EFI, 3.0L SHO, 3.8L SC, 4.0L EFI, 4.6L SEFI - DIGITAL VOLT-OHM MULTIMETER (DVOM) CHECK FOR IGNITION PINPOINT

TESTS - SERVICE TIPS


FORD: 1989-91 TAURUS, THUNDERBIRD 1991 ESCORT, MUSTANG

LINCOLN-MERCURY: 1989-91 COUGAR 1991 TOWN CAR, TRACER

LIGHT TRUCK: 1989-91 RANGER 1990-91 AEROSTAR, EXPLORER


ISSUE: True root means square (RMS) digital volt-ohm multimeters (Fluke 87, 8060A, 8062A, etc.) cannot be used with the Ignition Pinpoint Tests because they can display different voltage readings that may lead to misdiagnosis and unnecessary parts replacement. The Ignition Pinpoint Tests in the 1989 through 1991 Engine/Emissions Diagnosis Manuals require the use of an "averaging" type DVOM (Rotunda 007-00001, Fluke 88, Fluke 20 or 70 series, etc.).

ACTION: To determine if a DVOM can be used with the Ignition Pinpoint Test, perform the following test procedure.


1. Using a known good distributorless ignition system (DIS) or electronic distributorless ignition system (EDIS) ...

a. Install the proper DIS/EDIS diagnostic cable.

b. Connect the electronic ignition control (EEC) breakout box to the cable.


CAUTION: DO NOT CONNECT THE EEC PROCESSOR TO THE BREAKOUT BOX.

The DIS hand-held testers may also be used.

2. Start the engine. The battery should be charged and the engine must be idling between 700 and 900 rpm.

3. Measure the AC voltage between Coil Drive C1 and ground.
^ For Escort/Tracer, the voltage should be between 2.0 and 7.0 volts

^ For all other vehicles, the voltage should be between 1.0 and 2.0 volts.

4. Measure the AC voltage between the profile ignition pickup (PIP) jack and ground. The voltage should be between 6.0 and 8.0 volts.

5. If both of the readings are within the specifications, the DVOM can be used for ignition system diagnosis.

OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: INFORMATION ONLY
OASIS CODES: 203000, 290000, 690000