Crankshaft Position Sensor (CKP) - Difficult Starting

BULLETIN NUMBER:
SB00-01-S006

ISSUE DATE:
MAY 2000

GROUP:
ENGINE

NO HARD OR SLOW START, BACKFIRE OR KICKBACK DURING CRANK/START, OR UNUSUAL NOISES DURING CRANK, DTC P0338

AFFECTED VEHICLES

1996-2000 Hombre (TH) models with 4.3L V6 engines

SERVICE INFORMATION

Condition:

Some customers may comment on one or more of the following conditions:

^ Backfire during crank/start

^ Kickback during crank/start

^ No start

^ Slow or hard start/crank

^ Grinding or unusual noises during crank/start

^ Cracked or broken engine block at the starter boss

^ Broken starter drive housing

^ Broken starter ring gear on flywheel

Cause:

A condition may exist that allows the crankshaft position sensor to command up to 50 extra degrees of spark advance during engine cranking only. This in turn exposes the engine to higher than normal cylinder pressures which may result in an inoperative condition to the starter drive housing, the engine flywheel starter ring gear, or the engine block at the outside edge of the starter boss.

Correction:

Inspect for a stored powertrain DTC code P0338. This DTC will NOT illuminate the MIL (Malfunction Indicator Lamp). If this code is stored, the Crankshaft Position Sensor (part # 8-10456-607-0), must be replaced and the remaining components inspected for damage (engine block at the starter boss, the starter drive housing, and the engine flywheel starter ring gear).

NOTE:
When DTC Code P0338 is set, failure to replace the Crankshaft Position Sensor could result in repeated inoperative conditions of the starter or flywheel.

IMPORTANT:
Some flywheel wear is normal; broken or missed teeth and/or cracks, are not normal.

SERVICE PROCEDURE

1. Perform diagnostic procedures as described in the appropriate Workshop Manual and correct any other faults found prior to proceeding to step 2.





2. Remove the harness from the crankshaft position sensor (figure 1).

3. Remove the sensor hold down bolt (figure 1).

4. Remove the old sensor and replace with new sensor.

IMPORTANT:
When installing or removing a crankshaft position (CKP) sensor make sure that the mounting surfaces are clean and free of burrs before installing the CKP sensor and is fully seated and held stationary in the front cover before applying the torque settings to the hold down bolt. A sensor, which is not seated may result in erratic operation and may lead to setting false codes. Also, Lube the new o-ring with clean engine oil before installing.





PARTS INFORMATION

WARRANTY CLAIM INFORMATION





Use the published labor operation as shown.
Labor Time includes administrative time allowance.