K 2500 Truck 4WD V8-393 6.5L DSL Turbo (1992)
Oil Pressure Sender: All Technical Service Bulletins
Engine - Hesitation/Stalling/Low Power/White Smoke
BULLETIN NO: 93-6C-110
SECTION: 6C Engine Fuel
NUMBER: 5
CORPORATE REFERENCE NO: 276301R
DATE: August, 1993
SUBJECT:
STALLING/HESITATION/LOW POWER/WHITE SMOKE (CHECK LIFT
PUMP/CONDITION; NEW OIL PRESSURE SENDER/SWITCH AVAILABLE)
MODELS:
1992-93 C/K TRUCKS WITH 6.5L TURBO DIESEL (RPO L65) OR 6.2L DIESEL (RPOs LH6 and LL4)
THIS BULLETIN CANCELS AND REPLACES GMC TRUCK BULLETIN 92-6C-142 (CORP. # 276301) DATED OCTOBER 1992, AND IS
BEING REVISED TO ADD 1993 MODEL YEAR, ANNOUNCE A NEW OIL PRESSURE SWITCH PART NUMBER, AND ADD FURTHER
INFORMATION TO THE CORRECTION SECTION. ALL COPIES THE OF 92-6C-142 SHOULD BE DISCARDED.
CONDITION:
Any one or combination of the following:
-
Low power (continuous or intermittent)
-
Occasional stalling or hesitation on cold start
-
White smoke at high engine speed
Above conditions may occur on some 6.5L turbo-charged (VIN F) and 6.2L naturally aspirated (VINs C and J) diesel-powered vehicles.
CAUSE:
Improper electric lift pump operation, due to an inoperative lift pump electrical circuit OR a faulty pump. THE MOST PROBABLE CAUSE IS A
FAULT IN THE OIL PRESSURE SENDER/SWITCH CIRCUIT which operates the lift pump during engine operation. The oil pressure sender/switch
is located on the left bank, rear of the intake manifold.
A new oil pressure sender/switch, P/N 10243574, will be available from GMSPO August 30, 1993. This new part provides increased switch contact
durability, and was introduced into vehicle production late in the 1993 model year.
CORRECTION:
Check the operation of the lift pump first. It is located under the vehicle on the driver's side frame rail.
Lift pump operation can be checked by feeling its pumping action while the engine is idling. You should feel the rapid end-to-end oscillation of the
hollow plunger within the pump. Care should be taken not to confuse this oscillating with normal vehicle vibrations. If the pump is not operating, be sure
to check the pump's electrical supply circuits along with the actual condition of the pump.