Glow Plug - No Wait Lamp, Starting Difficulty
89chevy13GMC NUMBER: 89-T-28
GROUP: 6D - Engine Electrical
DATE: February, 1989
CORPORATE
NUMBER: 836414
SUBJECT: COLD START OR HOT RESTART DIFFICULTY WITHOUT GLOW PLUG WAIT LAMP
MODELS: 1983-89 C/K/R/V/G AND P MODELS WITH 6.2L DIESEL ENGINES (VIN CODE C,J)
Some customer comments have been received regarding no cold start capability or hot restart difficulty during mid-range engine temperature. Cases of no cold start may be the result of the glow plug inhibit switch not operating correctly. Reference Corporate Service Bulletin #866001 for glow plug system diagnosis.* Meanwhile, cases of poor hot/warm engine startup may be the result of starting system degradation, and may require glow plug assistance for engine starting. Replacement of the existing glow plug inhibit switch with a new service switch without a coolant temperature sensor (listed below) win provide glow plug assistance upon engine start, regardless of engine coolant temperatures. This feature will not reduce glow plug life.
New Part Numbers
1983-87 LH6*/LL4 - 23504005 1988-89 LL4(Only) - 23504006
* 1988-89 LH6 not equipped with glow plug inhibit switch
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 lbs./ft). Replace any lost coolant.
3. Connect glow plug inhibit switch connector assembly to service switch.
4. Reconnect batteries.
IMPORTANT: Glow plug operation (Wait Lamp) will be observed more frequently on the hot engine restarts with the installation of this service switch.
Parts are currently available from GMSPO.
* Chevrolet Bulletin #88-49, GMC Truck Bulletin
88-T-39 and GM of Canada #88-662-100
Use applicable labor operation number and time.