Engine - Knock On Acceleration After Cold Start
Article No.96-4-14
02-12-96
^ ENGINE - 4.0L - "KNOCK" ON HEAVY ACCELERATION DURING FIRST KILOMETER/MILE OF OPERATION AFTER COLD START - AMBIENT TEMPERATURE BELOW 10 DEGREES C (50 DEGREES F) - AUTOMATIC TRANSMISSION - VEHICLES BUILT THROUGH 2/6/95
^ NOISE - "KNOCK" ON HEAVY ACCELERATION DURING FIRST KILOMETER/MILE OF OPERATION AFTER COLD START - AMBIENT TEMPERATURE BELOW 10 DEGREES C (50 DEGREES F) - 4.0L ENGINE WITH AUTOMATIC TRANSMISSION- VEHICLES BUILT THROUGH 2/6/95
LIGHT TRUCK:
1995 EXPLORER
This TSB is being republished in its entirety to include additional calibrations.
CALIBRATION:
5-58B-R00, 5-58R-R00, 5-58B-R05, 5-58R-R05
WARNING:
THIS MODIFICATION IS AUTHORIZED ONLY FOR THE LISTED ENGINE. PERFORMING THIS MODIFICATION ON OTHER ENGINE CALIBRATIONS IS UNAUTHORIZED AND COULD CREATE LIABILITY UNDER APPLICABLE FEDERAL OR LOCAL LAWS.
ISSUE:
Some vehicles may have a "knock" noise from the engine on heavy acceleration during the first kilometer/mile of operation at temperatures below 1000 (50°F). This is due to the Powertrain Control Module (PCM) calibration having extra spark advance.
ACTION:
Replace the PCM with a PCM having a revised calibration. Refer to the following Service Procedure for details.
SERVICE PROCEDURE
1. If a low frequency metallic noise occurs on heavy acceleration during the first kilometer/mile of operation, after cold start at ambient temperatures below 1000 (50°F), replace the PCM. Refer to the Application Chart for the correct service part numbers. Refer to the 1995 Explorer Service Manual, Page 03-14-9, for removal and installation of the revised PCM.
2. Road test the vehicle and perform the EEC-IV Self Test. Confirm that there are no Diagnostic Trouble Codes (DTCs). If any codes appear, refer to the 1995 Engine/Emissions Diagnosis Manual for further assistance.
NOTE:
THE COLD ENGINE KNOCK CONDITION MAY BE AGGRAVATED BY A POSSIBLE EXHAUST LEAK, WHEN COLD, AT THE Y-PIPE-TO-EXHAUST MANIFOLD CONNECTION. CORRECTIVE ACTION FOR THE EXHAUST LEAK HAS BEEN DESCRIBED IN TSB ARTICLE 95-10-9.
Obtain an Authorized Modifications Decal and list the date, dealer number, and summary of modifications performed. Select a prominent place adjacent to the Vehicle Emission Control Information Decal suitable for installing the Authorized Modifications Decal. Clean the area, install the decal. and cover it with a clear plastic decal shield.
PART NUMBER PART NAME
F5TZ-12A650-ARC Powertrain Control Module (PCM)
F5TZ-12A650-ATC Powertrain Control Module (PCM)
OTHER APPLICABLE ARTICLES: 95-10-9
SUPERSEDES: 95-7-20
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME
960414A Replace Powertrain Control 0.3 Hr.
Module (PCM)
DEALER CODING
CONDITION
BASIC PART NO. CODE
RECAL 08
OASIS CODES: 497000, 702100, 703200