D250 3/4 Ton Pickup 2WD V8-318 5.2L VIN R 4-bbl (1982)
Technical Service Bulletin # 185386
Fuel System - Engine Vapor Lock
1981-1985 Pick-Up Truck & Ramcharger 4 x 4 or 4 x 2 Models Equipped With 5.2L or 5.9L Engine
December 8, 1986
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
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.
ORDER ONE OF THE FOLLOWING THREE PART NUMBERS:
Vapor Lock Package With 20 Gallon Fuel Tank
Vapor Lock Package With 30 Gallon Fuel Tank
Vapor Lock Package With 35 Gallon Fuel Tank
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
Refer to parts list for contents of each package.
Must be ordered separately: