FUEL SYSTEMS - 3B-790-817643R1 DECEMBER 1996
Troubleshooting Fuel Pump
PROBLEM: AIR BUBBLES IN FUEL LINE
Possible Cause Corrective Action
Low fuel in fuel tank. Fill tank
Loose fuel line connection Check and tighten
connections.
Fuel pump fitting loose. Tighten fitting.
A hole or cut in fuel line. Check condition of fuel
lines and replace any
found bad.
Fuel pump anchor Tighten all screws
screw(s) loose.
Fuel pump gasket(s) Rebuild fuel pump.
worn out.
PROBLEM: LACK of FUEL PUMP PRESSURE
Possible Cause Corrective Action
An anti-siphon valve Read “Checking for
Restricted Fuel Flow
Caused by Anti-Siphon
Valves” preceding.
Air in fuel line “Air Bubbles in Fuel Line,”
preceding.
A dirty or clogged fuel filter Clean or replace filter.
The fuel pickup in fuel tank Clean or replace pickup.
clogged or dirty.
Worn out fuel pump Rebuild pump.
diaphragm.
Defective (hole or crack) Rebuild pump.
check valve(s) in fuel
pump (unlikely).
Broken check valve Rebuild pump.
retainer.
Pulse hole plugged. Remove pump and clean
out hole.
Hole in pulse hose. Replace pulse hose
Loose pulse hose. Tighten connection.
Boost diaphragm gasket Check seal between mat-
distorted or out of place. ing surfaces where
“rib” divides pulse cham-
ber and gasket must align
with rib; check for dis-
torted gasket. Align or re-
place gasket if necessary.
IMPORTANT: Align diaphragm aligning tabs with fuel
pump aligning tabs during reassembly.
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