Mechanics

CRANKSHAFT SENSOR

1988 Buick Century

Electrical problem
1988 Buick Century 6 cyl Two Wheel Drive Automatic 50000 miles

The crankshaft position sensor went bad on my 88 Buick century with a 3.8 engine. I replaced the sensor and the car started up and ran fine. After turning the car off it will not start. I ohmed the sensor to find the sensor was bad. Purchased another sensor and after installation did the same thing. Car ran fine until turned off. I was very careful on the second install to make sure sensor was not getting hit by the fins. Could the sensor be getting to high of a voltage or could I be getting the wrong sensor? Any suggestions on what I should check?
Avatar
Dburgette
October 13, 2008.



Hi dburgette,

Hope the following explains the installation process.

CRANKSHAFT SENSOR
Removal
1. Disconnect crankshaft sensor harness connector.
2. Position harmonic balancer so that window in interrupter ring is lined up with sensor. Loosen sensor retaining bolt until sensor is free to slide in pedestal. Remove pedestal mounting bolts. Carefully remove sensor and pedestal as an assembly.

Installation
1. Loosen bolt on pedestal until sensor is free to slide in pedestal. Verify that window in interrupter ring is properly positioned. Install sensor and pedestal as an assembly. Install and tighten pedestal mounting bolts.
2. Rotate harmonic balancer until interrupter ring fills sensor slot and edge of window is aligned with edge of deflector on pedestal. Insert Crankshaft Position Sensor Adjuster (J-36179) into gap between sensor and each side of interrupter ring.
3. If gauge will not slide past sensor on either side of ring, sensor is out of adjustment or interrupter ring is bent. Check clearance at 3 positions around outer interrupter ring (about 120 degrees apart).

ADJUSTMENTS
CRANKSHAFT SENSOR
1. Loosen bolt on sensor pedestal and insert Position Sensor Adjuster (J-36179) into gap between sensor and interrupter on each side of ring. See Fig. 3 .
2. Make sure interrupter is sandwiched between blades of adjuster and both blades are properly inserted into sensor slot. Tighten sensor while maintaining light pressure on sensor.
3. A clearance of .025" (.64 mm) is required on either side of interrupter ring. Check clearance at 3 positions around outer interrupter ring (about 120 degrees apart). If interrupter ring contacts sensor at any point during harmonic balancer rotation, the interrupter ring is bent and must be replaced.


http://www.2carpros.com/forum/automotive_pictures/192750_CranksensorAdjustment88BuickCentury_1.jpg



IGNITION SYSTEM - C3I (FWD) -1988 Buick Century Custom 10/13/2006

KHLow2008
Oct 13, 2008.
The instructions you sent are just what I did twice. The sensor does not come in contact with the fin in the balancer. The problem is after I start the car and let it run for a few minutes the sensor goes bag. I have removed the sensor to check for marks from contact with the fin and there are no marks. I measuered the fins with a dial indicator and the are not bent. What voltage reading should I get at the sensor plug?

Tiny
Dburgette
Oct 13, 2008.
Hi dburgette,

The voltage should be between 2 to 5 volts.

KHLow2008
Oct 13, 2008.