Symptom, 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 restart until engine cools.
^ Engine may not sustain heavy loads.

PARTS REQUIRED

Order one of the following vapor lock package part numbers:

30 Gallon Fuel Tank PN 4364385
35 Gallon Fuel Tank (Ramcharger) PN 4364386
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 GAUGE READS EMPTY.

Must be ordered separately:

1 Wiring Assembly - Electric PN 4362804
Fuel Pump (I/P)
1 Authorized Modification Label PN 4275086

NOTE: DISCARD THE INSTRUMENT PANEL WIRING HARNESS, PN 4362284; THE TEMPLATE, PN 4418042; AND THE HOSE AND SLEEVE ASSEMBLY, PN 4418005; WHICH ARE SUPPLIED WITH THE KIT. THEY WILL NOT BE USED FOR 1988 MODEL YEAR VEHICLES.