Fuel System Maintenance Notes:
Periodic inspection and general maintenance is required for longevity and reliability of the fuel system. This action
directly affects the fuel pump's performance and reliability. Included with that are periodic inspection and/or filter
element replacement. The straining filter (upstream of pump) should be checked and cleaned at least every 30,000
miles (more often for off-road operating conditions). Replace or clean downstream filters (after pump) every year or
15,000 miles (more often for off-road operating conditions). Dirty fuel filters can block flow and adversely effect fuel
system performance as well as can directly damage the fuel pump.
Special alert for E85 Users:
DO NOT
use cellulose (paper) based filter elements! Water can contaminate the fuel
and break down the element, creating debris that can damage injectors and fuel pump. E85 and other oxygenated
fuels can absorb water. Long term storage of this fuel within the fuel tank of vehicle is not recommended and can
contribute to rusting of the fuel pump's tool steel components. Draining the fuel tank and replacement with small
amount of Gasoline or Kerosene (along with operating the fuel system for a small period of time) is recommended
for long term storage of the vehicle.
Troubleshooting Notes:
Problem (Symptom)
Possible Causes
Possible Solutions
Not operating or slight
"clicking" sound when
turned on.
Faulty fuel pump relay.
Faulty, dirty or corroded
terminals or improperly
sized wire.
Debris from tank or
plumbing lodged inside
pump.
Check voltage to controller, at power terminals.
If voltage is steady and consistent (within 1/2
Volt of battery) then contact Fuelab for
assistance or repair. If voltage is inconsistent
as described, repair or replace electrical
components as required.
Not building up fuel
pressure.
Incorrect fuel system initial
priming procedure.
Pump operating in reverse
direction (see above).
Repeat procedure for proper priming. If
condition continues, check all plumbing
upstream (on inlet side) of fuel pump.
Leakage of fuel at inlet or
outlet fuel ports.
Improper type of fitting
used.
If leakage is occurring between the end caps
and sleeve, contact Fuelab immediately for
repair or replacement. If leakage occurs at
fitting, be sure that the proper fitting style is
used (AN o-ring seal type ONLY!). Pipe
threaded style fittings are NOT to be used. If
proper style of fittings are being used, be sure
that o-ring is being used on fitting or replace o-
ring.
Loss of fuel pressure or
erratic pressure pulsation
after several minutes of
operation.
Cavitation (vapor lock) due
to overheating or restricted
inlet.
Check temperature of fuel line exiting or
entering tank right after failure. If line is hot to
touch (hot, or above 120°F), then look for
sources of heat such as exhaust or fuel rail
mountings that could be conducting too much
heat. If line or fittings are not hot to the touch,
check for inlet restrictions such as improperly
vented tank, or debris blocking inlet straining
filter. Contact Fuelab, as pump may be
damaged due to improper operating condition
for repair or consultation.
110021251-1, Rev B Sheet 7 of 8
