Vehicle - Cab Vibration/Body Boom

89ford13

Article No. 89-11-11

^ NOISE - "BOOM" AT IDLE - VEHICLES WITH 4.9L EFI ENGINE AND AUTOMATIC TRANSMISSION

^ VIBRATION - 4.9L EFI ENGINE AT IDLE-EQUIPPED WITH AUTOMATIC TRANSMISSION

LIGHT TRUCK: 1989 BRONCO, F-150


CALIBRATION: 7-52E-R10, 7-52G-R10, 7-52R-R10, 7-52Z-R10

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: A cab vibration or body "boom" may be caused by an engine vibration that is transmitted through the exhaust system. This condition is noticeable at engine idle when the transmission is in "DRIVE". The vibration is caused by the strategy of the EEC IV processor.

ACTION: Install a new EEC IV processor with revised operating strategy. Refer to the following procedure for service details.

1. Drive the vehicle to bring the engine to normal operating temperature.

2. Make sure the A/C is turned to the "OFF" position.

3. Let the engine idle with the transmission in the "DRIVE" position. If the vibration is present, put the transmission in "NEUTRAL".

4. If the vibration is less noticeable, install a new EEC IV processor. Refer to the following EEC IV processor application chart for the correct service part.

EEC IV PROCESSOR APPLICATION CHART

REMOVE
ENGINEERING INSTALL SERVICE
CALIBRATION PART PART

7-52E-R10 E8TF-12A650-BSA E8TZ-12A650-CFA
7-52G-R10 E8TF-12A650-BTA E8TZ-12A650-CCA
7-52R-R10 E8TF-12A650-BPA E8TZ-12A650-CBA
7-52Z-R10 E8TF-12A650-BRA E8TZ-12A650-CDA

NOTE: THE NEW EEC IV PROCESSOR WILL INCREASE THE BASE IDLE SPEED FROM 575 ENGINE RPM TO 640 ENGINE RPM.




Obtain an Authorized Modifications Decal and list the date, dealer number, and summary of alterations 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 CLASS

E8TZ-12A650-CFA EEC IV Processor C
E8TZ-12A660-CCA EEC IV Processor C
E8TZ-12A650-CBA EEC IV Processor W
EBTZ-12A650-CDA EEC IV Processor C

WARRANTY STATUS: Eligible Under Basic Warranty Coverage
OPERATION DESCRIPTION TIME
891111A Install EEC IV Processor 0.8 Hrs.
(includes road test)
DEALER CODING
BASIC PART NO. CONDITION CODE
DRIVE N4
OASIS CODES: 7210, 7214, 7100, 620800