EGR Valve/Engine - Piston Slap

83ford6 Article No. 83-23-14

NOISE - PISTON SLAP - (4.9L) COLD DRIVEAWAY UNDER LIGHT LOAD
- VEHICLES UNDER 8500 LB. GVW - ALL CALIBRATIONS


LIGHT TRUCKS 1981-83 E & F SERIES & BRONCO

CALIBRATIONS: All (3-52F, 3-52G, 3-52K, 3-52S, 3-52T, 3-52V should only use Step B)

Some units may experience a piston slap noise during cold engine high speed and light load conditions. The noise will usually occur within the first 2 miles of operation. The following procedures should resolve this concern. Perform vacuum schematic changes as noted for cold drive trickle EGR. Then, if necessary, replace pistons if the concern is not resolved.

Step A All 1981-83 vehicles except 1983 AOD calibrations 3-52F, 3-52G, 3-52K, 3-52S, 3-52T, 3-52V. These calibrations should only use Step B.

Figure 8:

1. Assemble a vacuum harness as shown in Figure 8.
2. Locate the EGR valve and remove the vacuum hose from the valve and connect it to the "C" end of the harness assembly.
3. Connect the "B" end of the harness assembly to the EGR valve.
4. Remove the hose from the carburetor EGR port and connect the "A" end of the harness to the EGR port.
5. Connect the hose that was removed from the EGR port to the other side of the "A" end of the harness.

Figure 9:

6. Verify correct vacuum routing using the vacuum schematic (Figure 9).

Step B

If the above procedure does not resolve the concern, replace the pistons with the revised pistons listed in the Parts List.

NOTE: As stated in the 1982 & 1983 Light Truck Engine Shop Manual, page 21-11-37, piston to bore clearance must be .0014 to .0022 and all procedures from Section 21-01 must be performed prior to new piston installation.




Obtain an Authorized Modifications decal and list the date, dealer number and summary of alterations performed. Select a prominent place adjacent to the Vehicle Emission Control Information decal suitable for installing the Authorized Modifications decal. Clean the area, install the decal and cover it with a clear plastic decal shield.

MODEL
PART NUMBER PART NAME YEAR CLASS

E2TZ-6108-A Piston Pin Assy. (Red) 1981-82 A
E2TZ-6108-B Piston Pin Assy. (Blue) 1981-82 B
E2TZ-6108-C Piston Pin Assy. 1981-82 B
(Yellow - .003 over)
E4TZ-6108-A Piston Pin Assy. (Red) 1983 B
E4TZ-6108-B Piston Pin Assy. (Blue) 1983 B
E4TZ-6108-C Piston Pin Assy. 1983 B
(Yellow - .003 over)
373846-S Tee B
D3TZ-12A091-C Vacuum Delay Valve A
D0PZ-12226-B Hose Rubber 5/32" ID AG

OTHER APPLICABLE ARTICLES: SEN 83-15
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.
OPERATION/TIME: Refer to the Labor Time Standards Manual for applicable operation and time.
DLR. CODING: Basic Part No. 6108 Code: 56