Engine - Knocking When Cold

85ford04

Article No. 85-4-24


ENGINE KNOCK - COLD - 3.8L

FORD 1984-85 LTD/THUNDERBIRD

LINCOLN-MERCURY 1984-85 MARQUIS/COUGAR

CALIBRATIONS: All 3.8L built from August '84 through April 1985.

WARNING: This modification is authorized only for the listed engines. Performing this modification on other engine calibrations is unauthorized and could create liability under applicable federal or local laws.

A nondestructive piston slap noise (only when engine is cold) can be caused by additional spark advance originally added to the cold spark calibration of the processor for improved cold driveaway. A new processor, with less cold start spark advance, will be released for production and service in May 1985. Until the new processor is available, the cold knock can be serviced by installing a different processor. When the different processor is installed, a light drive away hesitation may be experienced on some vehicles. Therefore, this processor should be installed only when the customer requires immediate resolution and cannot be deferred until the new part is available. A TSB article will be published when the new processor is available.

Use the following procedure:

1. Check the initial timing and set to 10~ BTDC if necessary.

2. Replace the EEC processor with E4VZ-12A650-CA (49 States) or E4VZ-12A650-DA (California).

3. Install a Ford Authorized Modification Decal denoting the changes.

Again, with these processors, a slight cold driveaway hesitation may be experienced. For this reason, this procedure should be used only if it is not possible to wait for the 1985 processors. After the 1985 processors are available, this procedure should not be used.

Authorized Modifications Decal:

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

E4VZ-12A650-CA Processor AM
E4VZ-12A650-DA Processor W

OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.

OPERATION: SP-12650-A-85
TIME: 0.5 Hr. DLR. CODING: Basic Part No. - Drive - Code: 56