Engine - Rough Idle During Cold Climatic Conditions
90pontiac18Bulletin Number: 90-6-38
Reference Number: 036513
Publish Date: 8/90
Subject: POOR DRIVEABILITY OR STARTABILITY WHEN COLD STARTING (DIAGNOSE, REMOVE/REPLACE PCV HOSE)
Models
Affected: 1988-90 LEMANS W/1.6L
CONDITION: Some 1988-1990 Pontiac LeMans may experience rough engine idle quality or poor driveability during certain cold climatic conditions, high humidity and extremely cold temperatures.
CAUSE: Moisture may collect and freeze in the PCV system vacuum source hose and restrict normal PCV operation. This may allow crankcase moisture to be vented through the air cleaner into the throttle body injector instead of being pulled in through the intake manifold.
DIAGNOSIS: Inspect the PCV vacuum hose (Figure 1). If the hose does not maintain a positive downward flow to the intake manifold (if a low spot is detectable) then the hose may be too long.
PROCEDURE:
1. Remove the hose from the vehicle and measure the length.
2. If the hose does not measure 160 mm, cut the hose to a length of 160 mm.
3. Reinstall the hose on the vehicle.
4. Verify that the hose maintains a positive downward flow to the intake manifold. If the hose does not maintain a positive downward flow (sagging condition) then additional length must be removed from the hose.
Labor Operation: T1661
Labor Time: .3 Hour