Engine - Miss or Stall During Deceleration
91ford27
Article No. 91-22-8
10/30/91
^ MISS - 4.9L - DURING DECELERATION AND/OR WHEN CLUTCH PEDAL IS DEPRESSED - VEHICLES WITH MANUAL TRANSMISSION
^ STALL - 4.9L - DURING DECELERATION AND/OR WHEN CLUTCH PEDAL IS DEPRESSED - VEHICLES WITH MANUAL TRANSMISSION
LIGHT TRUCK: 1990 BRONCO, F-150-350 SERIES
CALIBRATION: 0-51E, 0-51F, 0-51G, 0-51H, 0-51R, 0-71J
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: An engine miss or stall may occur during deceleration or when the clutch pedal is depressed. This is caused by the strategy of the EEC IV processor.
ACTION: Check the hard stop setting and, if necessary, install a new EEC IV Processor with improved strategy. Refer to the following procedure for service details.
1. Confirm the engine stall. Refer to the 1990 Engine/Emission-Diagnosis Shop Manual, Section 2, for routine diagnostics.
2. Check and confirm the correct idle hard stop setting (idle speed) per TSB Article 91-5-10.
^ If the setting is incorrect (low idle speed), check for sludge in the throttle body bores and the idle speed control motor. Follow the service procedure in TSB Article 91-10-9 and clean as necessary.
^ Recheck the hard stop setting and reset as required.
^ If the condition still persists, proceed to Step 3.
3. Determine the engine calibration number and replace the EEC IV processor. Refer to the Parts Block for correct parts usage.
4. Test the vehicle to confirm that the concern has been corrected.
NOTE: THE REPLACEMENT ECC IV PROCESSOR HAS A THREE (3) DIGIT SERVICE CODE SYSTEM AND WILL REQUIRE USE OF THE FOLLOWING CONVERSION CHART TO CONVERT THREE (3) DIGIT SERVICE CODES TO TWO (2) DIGIT SERVICE CODES.
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.
If it is necessary to run Self Test, refer to the following EEC IV Self Test Service Code Conversion Chart. Codes should be serviced in the order they are received and use the 1990 Engine/Emissions Diagnosis Manual for appropriate Pin Point Test.
PART NUMBER PART NAME CLASS
F0PZ-12A650-VA EEC IV Processor (cal. 0-51E) B
F0PZ-12A650-PA EEC IV Processor (cal. 0-51R) W
F0PZ-12A650-RA EEC IV Processor (cal. 0-71J) B
F0PZ-12A660-SA EEC IV Processor (cal. 0-51F) B
F0PZ-12A650-TA EEC IV Processor (cal. 0-51G) B
F0PZ-12A650-UA EEC IV Processor (cal. 0-51H) B
OTHER APPLICABLE ARTICLES: 91-10-9, 91-5-10
WARRANTY STATUS: Eligible Under Basic Warranty
Coverage, Emissions
Warranty Coverage
OPERATION DESCRIPTION TIME
912208A Verify Condition 0.3 Hr.
912208B Check Idle Speed 0.2 Hr.
912208C Check For Sludge In 0.2 Hr.
Throttle Body And ISC
Motor
912208D Clean Both Throttle Body 0.7 Hr.
And/Or Air By-Pass Valve
As Necessary
912208E Clean Only Air By-Pass 0.6 Hr.
Valve
912208F Replace Processor 0.3 Hr.
DEALER CODING
BASIC PART NO. CONDITION CODE
12A650 L9 OR N9
OASIS CODES: 607000, 607700, 609000, 609400