Engine - Loss of Power At High Engine Speeds

Article No.
92-3-8

01/29/92

LOSS OF POWER - 4.0L - AT HIGH ENGINE SPEEDS BETWEEN 3800 AND 4700 RPM - CANADIAN VEHICLES

LIGHT TRUCK:
1990-92 RANGER
1991-92 EXPLORER

ISSUE:
A loss of power may occur at engine speeds between 3800 and 4700 RPM under wide open throttle. After several months use, this can be caused by an interaction between MMT (octane enhancer additive in Canadian fuel) contaminated spark plugs and the EDIS (Electronic Distributorless Ignition System) module. A check engine light concern may be present with Self-Test Codes 18 (212 three digit code) and 45 in continuous memory.

ACTION:
If service is required, confirm the concern and, if necessary, replace the EDIS module and spark plugs. Refer to the following procedure for service details.

1. Confirm the customer concern by accelerating the vehicle at wide open throttle from 3000 RPM to 4700 RPM with the transmission in second gear.

^ If the vehicle exhibits a loss of power (caused by fuel shutoff of one of the fuel banks) in this RPM range, follow Steps 2 and 3.

^ Otherwise, follow the Powertrain Control/Emissions Diagnosis Manual's diagnostic procedures.

NOTE:
FUEL SHUTOFF (REV. LIMITER) AT 4850 RPM FOR AUTOMATICS AND 5200 RPM FOR MANUAL TRANSMISSIONS IS NORMAL AND SHOULD NOT BE CONFUSED WITH THIS CONCERN.

2. Replace all the spark plugs.

3. Replace the EDIS module (F1TZ-12KO72-B).

NOTE:
THIS MODULE WILL ELIMINATE THE PREMATURE FUEL SHUTOFF CONCERN. THE RED DEPOSITS ON THE SPARK PLUGS WILL STILL OCCUR AFTER TIME. THIS IS CONSIDERED NORMAL FOR THIS TYPE OF FUEL.

PART NUMBER PART NAME CLASS

F1TZ-12K072-B EDIS Module B
AWSF42C Spark Plug (Pkg / 10) BG
AWSF42P Spark Plug (Pkg / 10) B

OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under Bumper To Bumper Warranty Coverage For 1992 Models, Basic Warranty Coverage, Emissions Warranty Coverage

OPERATION DESCRIPTION TIME
920308A Replace Spark Plugs And 1.3 Hr.
EDIS Module
DEALER CODING
BASIC PART NO. CONDITION CODE
12K072 08

OASIS CODES: 614000, 614500