No Start, Hard Start, Rough Idle After Start (Clean CPI Poppet Valve). GMC Truck S15 Pickup - 4WD 1993

For 1990-2009 cars

# No Start, Hard Start, Rough Idle After Start (Clean CPI Poppet Valve)

Subject: | No Start, Hard Start, Or Rough Idle After Start (Clean CPI Poppet Valves)

Models: | 1992-1995 Chevrolet and GMC M/L, S/T Models

| 1992-1995 Oldsmobile Bravada

| with 4.3 L Engine (VIN W -- RPO L35)

### Condition

Some customers may comment on no start, hard start, rough idle after start, surge, or other driveability concerns related to the fuel system (clean CPI Poppet nozzles).

### Cause

Under certain conditions, fuel elements may deposit on the poppet balls, seats, or pintles, which can cause the poppet balls to stick in either an open or closed position.

### Correction

Follow the Strategy-Based diagnostics for your customer's specific driveability concern. If diagnosis leads to sticking poppet nozzles, this cleaning procedure should be performed prior to replacement of the CPI injector.

### CPI Injector Cleaning Procedure

1. Loosen the fuel filler cap to relieve vapor pressure in the fuel tank.
2. Raise the vehicle on a hoist.
3. Locate the underbody fuel line (1) junction point:

• | For S/T and L-van, it is along the left frame rail at approximately mid-vehicle.

• | For M-van, it is behind the left-front wheel housing.

Caution: Considerable fuel leakage may occur. Make sure that protective eyewear is worn, and that suitable fuel containment measures are taken.

4. Loosen and disconnect both the pressure and return lines at their junction points. The fittings towards the front of the vehicle (both pressure and return) have "male" fittings, and the fittings towards the rear of the vehicle have "female" fittings.
5. Install the J 44466-2 (1) (this hose has two 90 degree male fittings and no service port) to the "fuel tank" side of the fuel pressure and return lines. Installation of this hose eliminates the need to electrically disable the fuel pump and allows fuel to recirculate to the fuel tank.

Important: This cleaning procedure and service tools separate the fuel tank and pump from the cleaning process. Do not allow the Top Engine Cleaner solution to reach the fuel tank and/or pump. Top Engine Cleaner solution may cause a failure of the fuel pump.

6. Install the J 44466-1 (3) (this hose has two female fittings and a service port) to the "engine side" of the fuel pressure and return lines. Installation of this hose creates a "loop" through the hose and the engine side of the fuel system.
7. Obtain the J 35800-A (2). Make sure the valve at the bottom of the canister (3) is closed.
8. Remove the canister top and add 24 ml (0.8 fl.oz.) Top Engine Cleaner, GM P/N 1050002 (Canada P/N 992872), to the canister.
9. Fill the remainder of the canister with regular unleaded gasoline and install the canister top.
10. Suspend J 35800-A from a convenient location under the vehicle.
11. Connect the hose from J 35800-A to the service port on the J 44466-1.
12. Open the valve (3) at the bottom of J 35800-A.
13. Connect a "shop air" source to the fitting at the top of J 35800-A and adjust the regulator (1) to 75 psi.
14. Lower the vehicle to a convenient height and start the vehicle. It may be necessary to re-adjust the J 35800-A pressure regulator to maintain 75 psi.
15. Let the vehicle run at idle until the canister is empty and the vehicle stalls.
16. Turn OFF the vehicle ignition switch.
17. Raise the vehicle.
18. Remove the shop air supply from J 35800-A.
19. Depressurize J 35800-A.
20. Disconnect J 35800-A from J 44466-1.
21. Remove J 44466-1 and J 44466-2 from the vehicle fuel lines.
22. Re-connect the vehicle fuel lines.
23. Lower the vehicle.
24. Add one (1) ounce of Port Fuel Injector Cleaner, GM P/N 12345104 (Canada GM P/N 10953467), to the vehicle's fuel tank for each gallon of gasoline estimated to be in the tank. Instruct the customer to add the remainder of the bottle of Port Fuel Injector Cleaner to the vehicle's fuel tank at the next fill-up.
25. Tighten the fuel tank filler cap.
26. Start the engine and check for fuel leaks.
27. Clear any Powertrain DTC codes as required.
28. Advise the customer to change brands of fuel.

### Parts Information

Part Number | Description
--- | ---
1050002 | Top Engine Cleaner (U.S.)
992872 | Top Engine Cleaner (Canada)
12345104 | Port Fuel Injector Cleaner
10953467 | Port Fuel Injector Cleaner (Canada)

Parts are currently available from GMSPO.

### Warranty Information

For vehicles repaired under warranty, use:

Labor Operation | Description | Labor Time
--- | --- | ---
J5645 | Injector, Fuel - Clean | 0.8