HES. OR TIP-IN ACCELERATION INSTALL CHECK BALL SPRING KIT

HESITATION ON TIP-IN ACCELERATION

VEHICLES AFFECTED: 1986-87 B, F AND G PASSENGER CARS WITH ------------------ THE FOLLOWING FEDERAL 3C ENGINES; 5.0L LG4 ENGINE (ENGINE CODE H) OR 5.0L L69 ENGINE (ENGINE CODE G)

Some 1986 and early 1987 passenger cars equipped with 5.0L LG4 or L69 engines not featuring carburetor, P/N 17087306, may experience hesitation on sharp tip-in maneuvers with a fully warmed up engine.

This condition sometimes referred to as "pump slug" may be addressed by installation of a bi-metal accelerator pump check ball spring kit, P/N 17112032. This kit includes a pump discharge plug and a temperature compensated pump discharge ball spring. The original pump discharge ball should be used.

Service Procedure:

1. Disconnect the negative battery cable. 2. Remove the air cleaner. 3. Remove the carburetor air horn. (Refer to Section 6C1 of service manual if details of disassembly are needed). 4. Remove the solenoid adjusting screw plug from the air horn. 5. Remove the solenoid plunger, air horn gasket, accelerator pump assembly, metering rods and float bowl insert. 6. Count and record the number of turns of the solenoid adjusting screw required to lightly bottom the mixture control solenoid. 7. Remove the mixture control solenoid assembly. 8. Remove the float and needle. 9. Remove the pump discharge plug. 10. Install the new accelerator pump check ball spring and pump discharge plug provided in the kit, P/N 17112032. See Illustration. 11. Reinstall the float and needle. (Hook needle pull clip over float lever cross bar facing seat. Do Not Hook through holes in float lever). 12. Reinstall the mixture control solenoid. 13. Reinstall solenoid adjusting screw and turn it to lightly bottom solenoid, then back out the number of turns counted during disassembly. 14. Reinstall float bowl insert metering rods, pump assembly, air horn gasket and solenoid plunger. 15. Reinstall the carburetor air horn. 16. Reinstall the solenoid adjusting screw plug. 17. Reinstall the air cleaner. 18. Reconnect the negative battery cable.

Use applicable labour time and operation number.

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.