Engine - Spark Knock While Cruising Or Accelerating

Article No.
95-20-9

10/11/95

SPARK KNOCK - DETONATION WHILE CRUISING OR ACCELERATING AT HIGHWAY SPEEDS WHEN AMBIENT TEMPERATURES ARE 70 DEGREES F (21 DEGREES C) OR HIGHER - 2.3L ENGINE - VEHICLES WITH 4-49T-R00 CALIBRATION AND MANUAL TRANSMISSION, EXCEPT 4.10 AXLE

LIGHT TRUCK:
1994 RANGER

CALIBRATION:
4-49T-R00

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:
Spark knock/detonation may occur while cruising or accelerating at highway speeds with ambient temperatures of 70°F (21°C) or higher. This is due to too much spark advance.





ACTION:
Replace the Powertrain Control Module (PCM) with a revised PCM. Refer to the following Service Procedure for details.





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.

SERVICE PROCEDURE

1. Confirm that the cooling system is functioning correctly and that the customer is using 87 octane fuel. If detonation is still present, refer to the Quick Test procedure in the 1994 Engine/Emissions Diagnostics Manual. If fault codes are present, service them as required.

2. If pinging still occurs while cruising or accelerating at highway speeds with an ambient temperature of 70°F (21°C) or higher, replace the PCM. Refer to the Replacement Chart for the correct part numbers.

3. Test drive the vehicle and perform the EEC.IV self test. Confirm there are no Diagnostic Trouble Codes (DTCs).

PART NUMBER PART NAME
F4PZ-12A650-UA Powertrain Control Module (PCM)

OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under Emissions Warranty Coverage

OPERATION DESCRIPTION TIME
952009A Replacement Powertrain Control 0.3 Hr
Module (PCM)

DEALER CODING
CONDITION
BASIC PART NO. CODE
12A650 08

OASIS CODES: 499000, 615500, 615600, 702000