HARD START OR EXTENDED CRANK AFTER HOT OR COLD SOAK

VEHICLES AFFECTED: 1985-86 'A,J, F AND P' CARS EQUIPPED WITH 2.8L PFI ENGINES

Some 1985 and 1986 'A, J, F and P' cars with the 2.8L MPFI engine may experience a hard start condition after a hot soak (2 or more hours) or cold soak (overnight). This condition may be injector related, and should be diagnosed using procedures defined in the following steps.

NOTICE: THIS HARD START CONDITION SHOULD NOT BE CONFUSED WITH ROUGH IDLE OR POOR ACCELERATION DUE TO RESTRICTED FUEL INJECTORS. VEHICLES WITH ROUGH IDLE OR POOR ACCELERATION SHOULD BE SERVICED USING PROCEDURES FOR ON-VEHICLE CLEANING OF INJECTORS DEFINED IN PREVIOUS SERVICE BULLETINS.

1. Attach a fuel pressure gauge to the fuel rail pressure fitting. Turn ignition to "on" and pressurize fuel system.

2. If the fuel pressure leaks down more than 10 PSI in 2 minutes with the fuel feed and fuel return lines restricted, proceed to step 3. If the pressure does not leak down, perform procedures in Chart A-7, Fuel System Diagnosis, in section 6E3 of the service manual.

3. Locate and replace leaking injectors using the following procedure.

- Connect fuel gauge, J-34730-1 or equivalent to fuel pressure valve. Wrap around fitting while connecting gauge to avoid spillage. Route bleed hose into an approved container and open valve to ble'ed system.

- Remove plenum, cold start valve and remove fuel rail bolts. Leave fuel lines connected.

- Reconnect cold start valve. Connect one end of a hose to the nozzle of cold start valve and route the other end into a gasoline container.

- Lift fuel rails out just enough to leave injector nozzle in the ports.

CAUTION:

BE SURE INJECTOR(S) ARE NOT ALLOWED TO SPRAY ON ENGINE AND THAT INJECTOR RETAINING CLIPS ARE INTACT. THIS SHOULD BE CAREFULLY FOLLOWED TO PREVENT SPRAY ON ENGINE WHICH COULD CAUSE A FIRE HAZARD.

- Pressurize the fuel system.

- Lift each side of fuel rail up and observe for leaking injectors or cold start valve. Replace any parts that leak in excess of the following rates: Component Part Maximum Leak Rate *

Injector 1 drop / min.

Cold Start Valve 1 drop / min.

* Injectors and cold start valve should be wiped dry with a clean shop towel prior to timing the injector leak rate.

Use applicable labor times and operation numbers.

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.