C 2500 Truck 2WD V8-6.5L DSL Turbo VIN S (1997)
Engine Control Module: Customer Interest
Fuel - White Smoke, Rough Idle, Poor Throttle Response
File In Section: 6E - Engine Fuel & Emission
Bulletin No.: 77-65-26
Date: February, 1998
Subject:
White Smoke, Rough Idle, Poor Throttle Response on Cold Start
(Reflash with New Calibration)
Models:
1997 Chevrolet and GMC C/K, P Models
with 6.5L Diesel Engines (VINs S, F - RPOs L56, L65, L65-CMT) Built Prior to January 13, 1997 and the VIN Breakpoints as shown.
Important:
On P models, instead of VIN Breakpoints, please check current vehicle calibration versus the available calibration. Upgrade vehicle calibration if a
new calibration is available.
Condition
Some owners may experience white smoke, a rough idle, and poor throttle response on initial cold start. The condition may last up to several minutes
after initial start up.
It is possible that DTC P1216 or P1217 may be set during this condition, however often no DTC's will set. If Tech 2 failure records data are available, or
if the technician can monitor the vehicle when the condition occurs, the data may indicate that the desired idle speed and the actual idle speed do not
correspond, the actual will be lower than desired.
Also, the fuel solenoid closure time may exceed 3MS at idle, and the fuel rate is fixed at 10 mm. The condition will no longer exist when the engine
warms sufficiently, normally after a few minutes.
Do not replace the fuel injection pump for this condition.
Cause
Always perform normal diagnostics including an On Board Diagnostics (OBD) System check prior to making any repairs. The OBD System Check is
listed in the Engine Controls Section of the appropriate truck service manual. Diagnostics should also include checking for air or water in the fuel, cetane
rating, and glow plug operation. If this does not lead to problem resolution, the vehicle is most likely in the start logic mode of operation. When the
vehicle is operating in this mode, normal engine operation and throttle response are not possible.
Correction
Check the calibration identification number using a Tech 2 Scan tool, then check the techline terminal for an updated calibration number. Reflash with
