How to Change the Crank Sensor in a Buick 3100by Cayden Conor
The crank sensor in the Buick 3100 engine sits near the rear of the crankshaft pulley. One of its duties involves telling the computer when the No. 1 cylinder is at top dead center so the computer can adjust timing and the quantity of fuel and air entering the engine. If the crank sensor fails, most computers in the Buick 3100 engine will allow the vehicle to enter "limp home" mode, though the vehicle might not start in some cases. The computer sets to the last known good setting. The Buick will not run well, but it will get you home or to a repair shop.
Open the hood and stand on the passenger side of the engine compartment. Look down at the rear of the crankshaft pulley; you'll see the crankshaft sensor mounted in the timing cover, behind the pulley.
Unplug the wiring harness connector. If you cannot pry the plastic tabs open, use a screwdriver to "help" them spread enough so you can pull the plug off the sensor. Remove the sensor retaining bolts and pull the sensor out of the timing cover using a wrench or socket. Take care to remove the O-ring with the sensor, and do not allow it to stick in the timing cover.
Slide the O-ring onto the new sensor (it should come with a new O-ring); fit the O-ring into the indentation on the base of the sensor. Carefully slide the crank sensor into the timing cover. Reinstall the bolts, using a wrench or socket, and plug in the wiring harness.
Plug a code reader into the data port under the dash. Press the "Erase" button to erase the code for the crankshaft sensor.