W 150 Pickup V8-318 5.2L (1987)
Technical Service Bulletin # 180986A
Date: 861208
Fuel System - Engine Vapor Lock
Models
1986 & 1987 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.
18-09-86 REVISION A
P-4348
This bulletin authorizes the installation of the vapor lock package listed in Technical Service Bulletin 18-09-86 on 1987 Pick-Up Trucks and
Ramchargers. A new template for 1987 (4 x 2) vehicles only, to install the fuel reservoir/filter, is included in 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
Must be ordered separately:
1 - Wiring Assembly - Electric Fuel Pump Jumper (dash)
PN 4362558
1
Authorized Modification Label
PN 4275086
NOTE:
IT IS IMPORTANT THAT THE SPECIFIED FUEL TANK SIZE APPLICATION PACKAGE BE SELECTED. THE USE OF
AN IMPROPER PART NUMBER PACKAGE MAY CAUSE THE VEHICLE TO RUN OUT OF FUEL WELL BEFORE THE
