COLD PERFORMANCE POOR, STALL AND CODE 44 (DIAGNOSIS)

COLD STALL, COLD PERFORMANCE AND CODE 44 (Revised to Change Number from 625-122 to 625-115.)

VEHICLES AFFECTED: 1987 A AND N CARS EQUIPPED WITH ------------------ 2.5L ENGINES

Some 1987 "A" and "N" models equipped with 2.5L engines may experience poor cold performance and code 44, and may not stay running. In order to diagnose this condition, observe the block learn and integrator readings on the scan tool. The readings will be high indicating a lean exhaust condition.

Code 44 scan diagnosis in your service manual section 6E2 may correct the condition. If it does not, the following procedure may be used:

Check the fuel pressure using a 0-103 kPa (0-15 P.S.I.) gauge (J29658). If the fuel pressure is not within the specified 62-90 kPa (9-13 P.S.I.), repair the fuel system as necessary. If the fuel pressure is within specification, restrict the fuel return line which increases the fuel pressure and causes more fuel to be discharged from the injector. At the same time watch the integrator reading on your scanner. It should decrease. If the return line is restricted long enough both the integrator and block learn should stabilize closer together. This indicates a restricted fuel injector and it should be replaced.

NOTE: The block learn may read 128 with the car stopped and idling. It will be necessary to road test the vehicle to have the block learn number follow the integrator.

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.