B350 1 Ton Van V8-318 5.2L VIN R 4-bbl (1982)
Technical Service Bulletin # 181985A
Date: 851201
Fuel System - Vapor Lock
Models
1981-1985 Van & Wagon Models Equipped With 5.2L or 5.9L Engine
Subject
Vapor Lock
Index
DRIVEABILITY
Date
December 20, 1985
No.
18-19-85 REVISION A
P-4782-C
This bulletin supersedes Technical Service Bulletin #18-19-85 which should be removed from your files. The model application has been expanded to
include 1981 and 1982 model years.
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 TWO PART NUMBERS:
Vapor Lock Package With 22 Gallon Fuel Tank
PN 4397611
Vapor Lock Package With 36 Gallon Fuel Tank
PN 4397612
ADDITIONAL PARTS INFORMATION ON 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
All vehicles equipped with dual air conditioning, without electrically heated rear window defroster, and with 60 amp alternator must order the following
package in addition to the vapor lock package.
If vehicle is equipped with a 114 amp alternator, do not order this package or make any changes to the charging system.
1
78 AMP Alternator Package
PN 4397615
