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 MANUALSBUICK1991CENTURY L4-151 2.5L VIN R TBIREPAIR AND DIAGNOSISSPECIFICATIONSELECTRICAL SPECIFICATIONSCOMPUTERS AND CONTROL SYSTEMSSYSTEM SPECIFICATIONS
1991 Buick Century L4-151 2.5L VIN R TBI
System Specifications
1991 Buick Century L4-151 2.5L VIN R TBISECTION System Specifications
FUEL INJECTOR RESISTANCE VALUE
Injector [1] 1.2 Ohms min.
[1] Check across injector terminals.
THROTTLE POSITION SENSOR
Voltage [1] 0.33-1.33 volts
NOTE:
[1] The maximum TPS reading, at idle, is 1.33 volts. The TPS has an auto zeroing feature. If the voltage reading is within the range of about 0.33 to 1.33 volts, the ECM will use that value as closed throttle. If the voltage reading is out of the auto zero range at closed throttle, check for a binding throttle cable or damaged linkage.
ECM CONTROLLED RELAYS AND SOLENOIDS
Check the resistance of each ECM controlled relay or solenoid coil before replacing an ECM. Replace any relay or solenoid if the resistance measurement is less than 20 ohms. See ECM wiring diagrams under ELECTRICAL AND ELECTRONIC DIAGRAMS for coil terminal identification of solenoids and relays to be checked.
Injector [1] 1.2 Ohms min.
[1] Check across injector terminals.
THROTTLE POSITION SENSOR
Voltage [1] 0.33-1.33 volts
NOTE:
[1] The maximum TPS reading, at idle, is 1.33 volts. The TPS has an auto zeroing feature. If the voltage reading is within the range of about 0.33 to 1.33 volts, the ECM will use that value as closed throttle. If the voltage reading is out of the auto zero range at closed throttle, check for a binding throttle cable or damaged linkage.
ECM CONTROLLED RELAYS AND SOLENOIDS
Check the resistance of each ECM controlled relay or solenoid coil before replacing an ECM. Replace any relay or solenoid if the resistance measurement is less than 20 ohms. See ECM wiring diagrams under ELECTRICAL AND ELECTRONIC DIAGRAMS for coil terminal identification of solenoids and relays to be checked.
RENDER: 1.0x
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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.