Gran Fury V8-318 5.2L VIN K 2-bbl (1982)
Technical Service Bulletin # 184986
Fuel System- Engine Vapor Lock
1981 Through 1987 Diplomat, Gran Fury & New Yorker 5th Avenue Models Equipped With 5.2L Engine
September 2, 1986
This bulletin supersedes Technical Service Bulletin #18-16-85 REVISION A, which should be removed from your files. The model application has been
expanded to include 1981 through 1987 model years.
Symptom/Condition, Diagnosis & Parts Information
Engine performance is gradually reduced in high ambient temperature or high altitude driving due to a drop in fuel pressure, which starves engine for
fuel (goes lean). Engine may not start until fuel system components cool off.
The following are characteristics of vapor lock and should be observed on a fully warmed up engine. (Vapor lock does not affect cold engine
Occurs after hot soak, prolonged idle, or highway speeds at any throttle opening.
Sag due to lean mixture.
No black smoke at tailpipe.
Fuel pressure drops to 0.
Carburetor air horn dry.
No accelerator pump discharge.
May not start until engine cools.
Engine may not sustain heavy loads.
Vapor Lock Package
1981-1984 models equipped with Carter Thermoquad 4BBL carburetor must order the following package in addition to the vapor lock package:
Fuel Pressure Regulator Package
Refer to parts list for contents of each package.
Must be ordered separately:
Authorized Modification Label
To install electric fuel pump, regulator, and fuel reservoir.
A.Engine Compartment Harness Pn 4362295