D250 3/4 Ton Pickup 2WD V8-318 5.2L VIN R 4-bbl (1982)
Technical Service Bulletin # 185386
Date: 861201
Fuel System - Engine Vapor Lock
Models
1981-1985 Pick-Up Truck & Ramcharger 4 x 4 or 4 x 2 Models Equipped With 5.2L or 5.9L Engine
Subject
Vapor Lock
Index
DRIVEABILITY
Date
December 8, 1986
No.
18-53-86
P-4347
This bulletin supersedes Technical Service Bulletin #18-17-85 REVISION A which should be removed from your files. This bulletin is being revised to
include updated part numbers and the addition of a template to the parts kit.
Symptom/Condition, Diagnosis & Parts Information
SYMPTOM/CONDITION
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.
DIAGNOSIS
The following are characteristics of vapor lock and should be observed on a fully warmed up engine. (Vapor lock does not affect cold engine
driveability.)
^
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.
PARTS REQUIRED
ORDER ONE OF THE FOLLOWING THREE PART NUMBERS:
Vapor Lock Package With 20 Gallon Fuel Tank
PN 4364384
Vapor Lock Package With 30 Gallon Fuel Tank
PN 4364385
Vapor Lock Package With 35 Gallon Fuel Tank
PN 4364386
ADDITIONAL PARTS INFORMATION ON THE NEXT PAGE
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
PN 4397639
Refer to parts list for contents of each package.
Must be ordered separately: