Engine - Detonation/Spark Knock On Acceleration
Article No.97-21-6
10/13/97
^ DETONATION - DURING ACCELERATION -
VEHICLES BUILT THROUGH 8/97
^ NOISE - "SPARK KNOCK" DURING
ACCELERATION - VEHICLES BUILT THROUGH 8/97
FORD:
1996-97 CROWN VICTORIA
LINCOLN-MERCURY:
1996-97 GRAND MARQUIS, TOWN CAR
CALIBRATION:
6-18E-R05-R11, 6-18F-R05-R11, 6-18H-R05-R11, 6-18I-R05-R12, 6-18J-R05-R11, 6-18M-R05-R11, 6-18N-R05-R11, 6-18Q-R05-R11, 6-18S-R05-R11, 7-18E-R10, 7-18F-R05-R10, 7-18H-R05-R10, 7-18I-R05-R11, 7-18J-R10, 7-18M-R05-R10, 7-18N-R05-R10, 7-18Q-R10, 7-185-R10
All prior calibration revision levels to the calibrations listed above are also included in this TSB.
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 experience detonation during acceleration. This may be caused by contamination of the Mass Air Flow (MAF) sensor which then misinterprets the barometric pressure resulting in a leaner than desired condition.
ACTION:
Replace the MAF sensor and reprogram the Powertrain Control Module (PCM). The sensor has been revised to reduce the possibility of contamination and reduce the possibility of spark knock. Refer to the following text and PCM Application Chart for details.
If detonation occurs during moderate to wide open throttle, verify the barometric pressure sensor output is above 148 Hz. This can be accomplished by using the New Generation Star (NGS) Tester and by calling up the Parameter Identification Display (PID) called "BARO" or "BP" depending on which level of NGS software is used.
^ If the "BP" is 148 Hz or less, disconnect the MAF sensor hardshell connector. Cycle the ignition key twice and drive the vehicle until the Malfunction Indicator Lamp (MIL) is illuminated. Verify that the 'BP" has gone to 157 Hz (default FMEM value) and try to duplicate detonation concern.
^ If the detonation is eliminated, replace the MAF sensor.
NOTE:
REGIONAL APPROVAL MUST BE OBTAINED WHEN IT IS NECESSARY TO REPLACE THE PCM. EMERGENCY ORDERS ONLY WILL BE FILLED AS SHELF STOCK OF PCMs ARE LIMITED.
For vehicles that exhibit detonation during 3rd gear with the torque converter at approximately 50% lockup, 35-48 km/h (22-30 mph), light throttle, the PCM will have to be reprogrammed to the latest level. Check the emissions decal to verify the vehicle does not have the latest level calibration. Reprogram the PCM to the latest level using Service Bay Diagnostic System (SBDS) or NGS Tester and the September CD-ROM. Refer to the PCM Application Chart for the correct PCM.
If neither of the above resolves the concern, remove the octane adjust shorting bar and redrive the vehicle to verify the concern has been eliminated.
Obtain an Authorized Modification Decal (FPS 8262 - obtainable through DOES II, 25/pkg) 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.
Parts Block
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage And Emissions Warranty Coverage
OPERATION DESCRIPTION TIME
972106A Replace Mass Air Flow 0.3 Hr.
(MAF) Sensor
9721O6B Reprogram Powertrain 0.2 Hr.
Control Module (PCM)
972106C Replace Powertrain Control 0.4 Hr.
Module (PCM) - Town Car
972106D Replace Powertrain Control 0.3 Hr.
Module (PCM) Crown
Victoria/Grand Marquis
DEALER CODING
CONDITION
BASIC PART NO. CODE
12B579 49
OASIS CODES: 497000, 615000, 615500