NO COLD START OR HOT RESTART DIAGNOSIS/PART NUMBER

Model and Year: 1983-89 LIGHT DUTY TRUCKS, G AND P VANS WITH 6.2L (VIN CODES J, C) ENGINE

Some customer comments have been received regarding no cold start capability or restart difficulty during mid-range engine temperature.

This can occur in cases of no cold start when the inhibit switch is not operating correctly. Reference Chevrolet Dealer Service Bulletin 88-49 (Section 6B) for glow plug system diagnosis. Or in cases of hot restart difficulty, due to engine starting system degradation over time, the starting system is not at optimum performance, requiring glow plug assistance to start.

Replacement of the existing glow plug inhibit switch with a revised switch without a sensor allows glow plug assistance for enhanced startability.

YEAR/ PART NUMBER ENGINE W/0 SENSOR ------ -----------

83-87 23504005 LHG6/LL4

88-89 23504006 LL4 Only

Parts are expected to be available on December 5, 1988. Until then normal part orders will not be accepted by GMSPO. Only verifiable emergency VIP orders will be accepted. SPO will make every effort to obtain parts. All parts will be placed on 400 control to waive VIP surcharges. However, the part will be shipped premium transportation at dealer's expense. All other order types will be canceled as incorrectly ordered while the 400 control is in place.

Service Switch Without Sensor Installation

1. Disconnect batteries

2. Replacement service switch can be installed in exact location of the inhibit switch with a socket wrench, do not use open end wrench. Tighten to 19-27 N.m. (13-20 ft. lb.). Replace any lost coolant.

3. Connect glow plug inhibit switch connector assembly to service switch.

4. Reconnect batteries.

NOTICE: GLOW PLUG OPERATION (WAIT LAMP) WILL BE OBSERVED MORE FREQUENTLY ON THE HOT ENGINE RESTARTS WITH THE INSTALLATION OF THIS SERVICE SWITCH.

Use applicable labor operation number and time.

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.