Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSFORD1990RANGER 4WD L4-140 2.3L SOHCREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTIGNITION SYSTEMTECHNICAL SERVICE BULLETINSALL TECHNICAL SERVICE BULLETINSOCTANE ADJUST SHORTING BAR - REVISED PROCEDURESOVERVIEW
1990 Ford Ranger 4WD L4-140 2.3L SOHC
Octane Adjust Shorting Bar - Revised Procedures: Overview
1990 Ford Ranger 4WD L4-140 2.3L SOHCSECTION Overview
Article No.
91-11B-6
^ ENGINE/EMISSIONS DIAGNOSIS MANUAL - 1989 - PAGE 17-289 - PINPOINT TEST KP REVISED TO PROVIDE ADDITIONAL INFORMATION CONCERNING REMOVAL OF OCTANE ADJUST SHORTING BAR
^ ENGINE/EMISSIONS DIAGNOSIS MANUAL - 1990 - PAGE 17-329 - PINPOINT TEST KP REVISED TO PROVIDE ADDITIONAL INFORMATION CONCERNING REMOVAL OF OCTANE ADJUST SHORTING BAR
^ ENGINE/EMISSIONS DIAGNOSIS MANUAL - 1991 - PAGE 5-22 - EEC-IV QUICK TEST STEP 12.0 - CAR DIAGNOSIS BY SYMPTOM CHART REVISED
^ ENGINE/EMISSIONS DIAGNOSIS MANUAL - 1991 - PAGES 6-305 THROUGH 6-307 - PINPOINT TEST KP REVISED TO PROVIDE ADDITIONAL INFORMATION CONCERNING REMOVAL OF OCTANE ADJUST SHORTING BAR
FORD:
1989-91 TAURUS, THUNDERBIRD
1991 ESCORT, MUSTANG
LINCOLN-MERCURY:
1989-90 COUGAR
1991 TRACER
LIGHT TRUCK:
1989-91 RANGER
1991 AEROSTAR, EXPLORER
ISSUE:
Additional information regarding removal of the Octane Adjust Shorting Bar is required to assure compliance with Federal (EPA) Emission Standards. The following Manuals are affected on the pages indicated:
^ 1989 Engine/Emissions Diagnosis Page 17-289
^ 1990 Engine/Emissions Diagnosis Page 17-329
^ 1991 Engine/Emissions Diagnosis Page 5-22 and Pages 6-305 through 307
ACTION:
Refer to the pages in this TSB article for the additional information.
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: INFORMATION ONLY
OASIS CODES: 690000
91-11B-6
^ ENGINE/EMISSIONS DIAGNOSIS MANUAL - 1989 - PAGE 17-289 - PINPOINT TEST KP REVISED TO PROVIDE ADDITIONAL INFORMATION CONCERNING REMOVAL OF OCTANE ADJUST SHORTING BAR
^ ENGINE/EMISSIONS DIAGNOSIS MANUAL - 1990 - PAGE 17-329 - PINPOINT TEST KP REVISED TO PROVIDE ADDITIONAL INFORMATION CONCERNING REMOVAL OF OCTANE ADJUST SHORTING BAR
^ ENGINE/EMISSIONS DIAGNOSIS MANUAL - 1991 - PAGE 5-22 - EEC-IV QUICK TEST STEP 12.0 - CAR DIAGNOSIS BY SYMPTOM CHART REVISED
^ ENGINE/EMISSIONS DIAGNOSIS MANUAL - 1991 - PAGES 6-305 THROUGH 6-307 - PINPOINT TEST KP REVISED TO PROVIDE ADDITIONAL INFORMATION CONCERNING REMOVAL OF OCTANE ADJUST SHORTING BAR
FORD:
1989-91 TAURUS, THUNDERBIRD
1991 ESCORT, MUSTANG
LINCOLN-MERCURY:
1989-90 COUGAR
1991 TRACER
LIGHT TRUCK:
1989-91 RANGER
1991 AEROSTAR, EXPLORER
ISSUE:
Additional information regarding removal of the Octane Adjust Shorting Bar is required to assure compliance with Federal (EPA) Emission Standards. The following Manuals are affected on the pages indicated:
^ 1989 Engine/Emissions Diagnosis Page 17-289
^ 1990 Engine/Emissions Diagnosis Page 17-329
^ 1991 Engine/Emissions Diagnosis Page 5-22 and Pages 6-305 through 307
ACTION:
Refer to the pages in this TSB article for the additional information.
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: INFORMATION ONLY
OASIS CODES: 690000
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.