LOOSE EGR SOLENOID CONNECTION ENGINE SURGE/TOO MUCH EGR

MODELS AFFECTED: 1983 Centurys Equipped With 3.OL Engines

A surging condition on a 3.OL engine could be caused by a loose Pulse Width Modulated (P.W.M.) EGR Valve electrical connector.

The P.W.M. solenoid pack is mounted on the rocker arm cover next to the cowl panel (See Figure 1).

If the connector is loose, the electrical connection is removed from the solenoid, which allows full manifold vacuum to the EGR valve (See Figures 2 and 3).

When checking and installing connector, squeeze locking tab to assure a positive lock within the P.W.M. housing.

Also, check the vacuum harness on the P.W.M. solenoid pack to assure the ports on the pack are installed into the vacuum harness correctly. A vacuum leak can cause a rough idle and is usually detected by a 10 DEG or below dwell meter reading (See Figure 4).

Other possible items that could cause poor driveability:

Light surge may be caused from timing set below specs.

Vacuum leaks at:

a. EFE Assembly to Vacuum Pipe b. Hose at carburetor location "V" cut c. Hose off or nipple cracked at air management valve d. Intake Manifold e. A/C Vacuum Tank f. EFE/EGR Solenoid Hoses reversed g. Air Cleaner Vacuum Hose (Thermac) h. A/C Water Valve Hose disconnected i. EFE Check Valve cracked or broken

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.