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 MANAGEMENTTECHNICAL SERVICE BULLETINSBY SYMPTOMSTARTING PROBLEMSFUEL PUMP - BUZZING/HUMMING AFTER ENGINE SHUT DOWN
1990 Ford Ranger 4WD L4-140 2.3L SOHC
Fuel Pump - Buzzing/Humming After Engine Shut Down
1990 Ford Ranger 4WD L4-140 2.3L SOHCSECTION Fuel Pump - Buzzing/Humming After Engine Shut Down
90ford25
^ NO START - 1.9L, 2.3L, 3.0L, 3.8L, 4.9L, 5.0L, 5.8L, 7.5L - LOW STATE OF BATTERY CHARGE
^ BATTERY - DISCHARGED - 1.9L, 2.3L, 3.0L, 3.8L, 4.9L, 5.0L, 5.8L, 7.5L
^ FUEL PUMP - NOISY - 1.9L, 2.3L, 3.0L, 3.8L, 4.9L, 5.0L, 5.8L, 7.5L
^ NOISE - "BUZZING" OR "HUMMING" FROM FUEL PUMP AFTER ENGINE IS TURNED OFF
Article No. 90-18-3
FORD: 1983-90 CROWN VICTORIA, ESCORT, EXP, MUSTANG, TEMPO, THUNDERBIRD 1986 LTD 1986-90 TAURUS
LINCOLN-MERCURY: 1983-87 LYNX
1983-90 CONTINENTAL, COUGAR, GRAND MARQUIS, MARK VII, TOPAZ, TOWN CAR 1985-86 CAPRI, MARQUIS 1986-90 SABLE
LIGHT TRUCK: 1983-90 BRONCO II, BRONCO, ECONOLINE, F-150, F-250, F-350, RANGER 1988-90 F SUPER DUTY
ISSUE: A "buzzing" or "humming" noise from the fuel pump may occur after the engine has been shut off. There may also be a no start condition or a discharged battery. These conditions are caused by a sticking fuel pump relay.
ACTION: Install a new fuel pump relay. Refer to the following procedure for service details.
1. Check the fuel pump relay circuit for proper operation. Refer to the appropriate EVTM for troubleshooting details.
2. Install a new fuel pump relay, if the old one is defective.
3. Check the vehicle for proper operation.
PART NUMBER PART NAME
F19Z-9345-A Fuel Pump Relay Assy.
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Eligible Under Basic Warranty Coverage
OPERATION DESCRIPTION TIME
901803A 1985-86 LTD/Marquis 0.6 Hr.
(includes pinpoint test)
901803A 1990 Town Car (includes 0.4 Hr.
pinpoint test)
901803A All Other Cars (includes 0.5 Hr.
pinpoint test)
901803A All Trucks (includes pinpoint 0.5 Hr.
test)
DEALER CODING
BASIC PART NO. CONDITION CODE
9345 09
OASIS CODES: 404000, 603300, 203000, 203100, 702000
^ NO START - 1.9L, 2.3L, 3.0L, 3.8L, 4.9L, 5.0L, 5.8L, 7.5L - LOW STATE OF BATTERY CHARGE
^ BATTERY - DISCHARGED - 1.9L, 2.3L, 3.0L, 3.8L, 4.9L, 5.0L, 5.8L, 7.5L
^ FUEL PUMP - NOISY - 1.9L, 2.3L, 3.0L, 3.8L, 4.9L, 5.0L, 5.8L, 7.5L
^ NOISE - "BUZZING" OR "HUMMING" FROM FUEL PUMP AFTER ENGINE IS TURNED OFF
Article No. 90-18-3
FORD: 1983-90 CROWN VICTORIA, ESCORT, EXP, MUSTANG, TEMPO, THUNDERBIRD 1986 LTD 1986-90 TAURUS
LINCOLN-MERCURY: 1983-87 LYNX
1983-90 CONTINENTAL, COUGAR, GRAND MARQUIS, MARK VII, TOPAZ, TOWN CAR 1985-86 CAPRI, MARQUIS 1986-90 SABLE
LIGHT TRUCK: 1983-90 BRONCO II, BRONCO, ECONOLINE, F-150, F-250, F-350, RANGER 1988-90 F SUPER DUTY
ISSUE: A "buzzing" or "humming" noise from the fuel pump may occur after the engine has been shut off. There may also be a no start condition or a discharged battery. These conditions are caused by a sticking fuel pump relay.
ACTION: Install a new fuel pump relay. Refer to the following procedure for service details.
1. Check the fuel pump relay circuit for proper operation. Refer to the appropriate EVTM for troubleshooting details.
2. Install a new fuel pump relay, if the old one is defective.
3. Check the vehicle for proper operation.
PART NUMBER PART NAME
F19Z-9345-A Fuel Pump Relay Assy.
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Eligible Under Basic Warranty Coverage
OPERATION DESCRIPTION TIME
901803A 1985-86 LTD/Marquis 0.6 Hr.
(includes pinpoint test)
901803A 1990 Town Car (includes 0.4 Hr.
pinpoint test)
901803A All Other Cars (includes 0.5 Hr.
pinpoint test)
901803A All Trucks (includes pinpoint 0.5 Hr.
test)
DEALER CODING
BASIC PART NO. CONDITION CODE
9345 09
OASIS CODES: 404000, 603300, 203000, 203100, 702000
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.