Fuel Line - Knocking Noise

Bulletin No.: 005/94
Issued: 4/8/94
Revised: 5/19/94

Category
F

Applicable Model/s
1991-92 Navajo

Subject:
FUEL LINE KNOCKING NOISE

Revised section of this bulletin is indicated by an asterisk (*). Replace the original bulletin with this revised copy.

APPLICABLE MODELS/VINS
1991-92 Navajo vehicles built prior to 12/1/91

DESCRIPTION

Some vehicles may have a fuel line knocking noise. This noise is similar to a bearing/piston knock but does not occur in time with engine revolution and is most evident in temperatures below 45 degrees F. The fuel line knocking noise is caused by hydraulic pulsations in the fuel line.

REPAIR PROCEDURE
Follow the procedures in this bulletin to install a new fuel line assembly

1. With the vehicle idling, confirm fuel line knocking with a mechanic's stethoscope on the fuel line. If knocking is heard, proceed to step 2. If knocking is not occurring in the fuel line, refer to the workshop manual for troubleshooting procedures.

WARNING:
FOLLOW ALL OSHA AND WORKSHOP SAFETY PROCEDURES WHEN WORKING ON FUEL SYSTEM COMPONENTS.

2. Remove the fuel supply manifold. Refer to the instruction in section F-02-7 of the workshop manual.
3. Locate the engine/chassis fuel line couplers in the engine compartment.

^ Remove the fuel line safety clips. Refer to the instructions in section F-03-10 of the 1991 workshop manual.
^ Disconnect the fuel line spring lock connectors.





4. Remove the fuel line bracket/cylinder block bolt as shown in figure 1.

5. Install new fuel supply manifold. Refer to steps 1-5 only of section F-02-06 "Fuel Supply Manifold Assembly" - Installation Procedures.





6. Install new fuel line. Refer to steps 6-8 of section F-02-08 of the workshop manual.
7. Fasten fuel line assembly bracket to the cylinder block. Tightening Torque: 30-41 ft.lbs. (40-55 N-m)
8. Fasten damper portion of the fuel line assembly to the fuel supply manifold using the screw described in the PARTS INFORMATION section of this bulletin. Tighten Torque: 6-7 ft.lbs. (8-9 N-m)
9. Complete steps 9-13 of the fuel supply manifold installation procedures.
10. Connect fuel line lock connectors and install safety clips.
11. Complete steps 14 and 15 of the fuel supply manifold installation procedures.
12. Inspect the fuel system for leaks according to the instructions in the workshop manual.

PARTS INFORMATION*

Part Number Description

ZZLO 13 150A Fuel Supply Manifold

ZZLO FF 005 Fuel Line Assembly

ZZLO FF 006 M6 Locking Screw

ZZL0 13 111 Fuel Rail Gasket (2 Req.)

WARRANTY INFORMATION
(Applies To Vehicles Covered Under Normal Warranty)

Warranty Type: A
Customer Comment Code: 11
Damage Code: 97
Part Number Main Cause: ZZLO FF 005
Quantity: 1
Operation Number YY0062RX
Labor Hours: 1.6Hrs.