Technical Guide
08/15/14
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Table of Contents
Contact information…………………………………….3
Identifying your system………………………………..4-8
Model Number
Serial number location
Parts of your fuel system………………………………..9-14
Fuel pump diagram
Wire harness schematics
Fuel line diagram
Servicing Your FASS or Fuel Pump Filters…………….15-18
Recommended Service Life
Procedures for servicing your filters/separator
How to prime your FASS system……………………….19
Trouble shooting………………………………..……….20-21
How to do a 5 gallon bucket test………………………..22
Electrical………………………………………………...23
‘98.5-02 Hard Start Issues………………………………24-25
Fuel Leak………………………………………………..26
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Contact us:
Diesel Performance Products Inc.
16240 State Hwy O
Suite B
Marthasville, MO 63357
Phone: 636-433-5410
Fax: 636-433-5913
Email: techsupport@fassride.com
When contacting FASS for technical assistance
please have the Serial number of the pump
ready.
3
Identify your
Fuel system
4
DDRP/DMAX
Series
Serial number and model number on the DDRP or
DMAX will be located on the motor casing of the fuel
pump.
5
FA Series
Serial number and model number on the Fuel pump series will be on the suction side of the pump next to the
inlet(“T” port) of the pump.
6
Platinum Series
Serial number and model number on the Platinum series
will be located on the filter base, above the filter base
and opposite of the truck frame rail.
7
Titanium/ Heavy
Duty Series
Serial number and model number on the Titanium or
Heavy Duty series will be located on the filter base
above the fuel filter.
8
Parts of your
Fuel system
9
DDRP/DMAX
Series
Mounting bracket
Fuel inlet( suction
side of fuel pump)
marked with “IN”.
Located opposite of
outlet. 12mm O-ring
Outlet( suction side of
pump).
Marked with
“OUT”.
12mm O-ring
The weep hole is on opposite
side of mounting bracket. Always be sure weep hole points
down. Weep hole is for normal moisture to exit the motor
Electrical plug, Green
wire is ground and Red
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FA Series
Inlet( suction
side of pump)
Marked with a
“T” for tank.
1/2” NPT
The FA Series is factory preset
for each truck, the pump is adjustable by using the regulator
Outlet( pressure side of
pump) Marked with an
“E” for Engine. 1/2”
Electrical plug, Green
wire is ground and Red
wire is power.
Boost compensating
port for high horse
power applications
Weep hole is for normal moisture
to exit the motor casing. Weep
hole must be facing down
1/8” NPT fuel pressure
port
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Platinum Series
Engine feed
( pressure side)
marked with an
“E: for Engine.
3/8” NPT
FASS return
( pressure
side) Marked
with a “R” for
return. 1/2”
male flare.
3/8” NPT fuel
pressure port
Fuel inlet( suction
side). 3/8” NPT
Electrical plug, Green
wire is ground and Red
wire is power.
Fuel filter/water separator( pressure side) recommended to use at least a 3 micron filter or better
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Titanium Series
Electrical plug, Green
wire is ground and Red
wire is power.
Engine feed
( pressure side)
marked with an
“E: for Engine.
3/8” NPT
FASS return
( pressure side)
Marked with a
“R” for return
1/2” male flare.
Fuel filter
( pressure side)
recommended
to use at least a
3 micron filter
or better
Fuel inlet( suction side)
marked with a
“T” for Tank.
3/8” NPT
1/8” NPT
fuel pressure
port
Water separator
( suction side)
recommended to
us no more restrictive than a 10
micron filter
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Titanium Series
Electrical plug, Green
wire is ground and Red
wire is power.
Engine feed
( pressure side)
marked with an
“E: for Engine.
1/2” NPT
FASS return
( pressure side)
Marked with a
“R” for return
1/2” male flare.
Fuel filter
( pressure side)
recommended
to use at least a
3 micron filter
or better
Fuel inlet( suction side)
marked with a
“T” for Tank.
1/2” NPT
1/8” NPT
fuel pressure
port
Water separator
( suction side)
recommended to
us no more restrictive than a 10
micron filter
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Heavy Duty Series
Electrical plug,
Green wire is
ground and
Red wire is
power.
Engine feed
( pressure side)
marked with an
“E: for Engine.
1/2” NPT
FASS return
( pressure
side) Marked
with a “R” for
return 1/2”
male Flare.
Fuel filter( pressure
side) recommended to
use at least a 3 micron
filter or better
Fuel inlet( suction side)
marked with a
“T” for Tank.
1/2” NPT
1/8” NPT fuel
pressure port
Water separator( suction side) recommended to us no more restrictive than a 10 micron filter
15
Servicing your
FASS filters
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Filter Intervals
FASS DDRP/DMAX
 In line filter 4,000-6,000 miles*
 Refer to vehicle owners manual for factory fuel filter
FASS FA Series
 Inline filter 4,000-6,000 miles*
 Refer to vehicle owners manual for factory fuel filter
FASS Platinum Series
 In line filter 4,000-6,000 miles*
 Spin on fuel filter/water separator 15,000-25,000
miles*
FASS Titanium Series
 Water separator 25,000-30,000 miles*
 Fuel filter 25,000-30,000 miles*
FASS Heavy Duty Series
 Water separator 50,000 miles*
 Fuel filter 50,000 miles*
*Intervals will depend on quality of fuel being used.
FASS always recommends a fuel pressure gauge to
monitor filter life.
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How to change
your filters
Inline filter
 If possible crimp off suction line( line from tank to FASS
pump) to prevent large fuel leaks
 Loosen hose clamps
 Using proper container pull fuel lines off each end of the
fuel filter.
 Replace with new filter (from cross reference sheet) be
sure to pay attention to flow of the filter
 Tighten hose clamps
 Remove crimps if used
Prime pump
 Using proper container to catch fuel loosen a fitting on
pressure side of and bump the starter, may need to do several times, do not let pump shut off until system is primed
 Tighten once fuel comes out
Spin on water separator
 Using proper container to catch fuel, drain water separator
and remove
 Replace with new water separator (from cross reference
sheet) and follow directions on filter when installing
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How to change
your filters
Priming
 Using proper container to catch fuel loosen fuel filter
and bump starter, may need to do several times, do not
let pump shut off until system is primed
 When the FASS motor changes tone tighten fuel filter
Spin on fuel filter or fuel/water separator
 Using proper container to catch fuel drain or remove
fuel filter
 Replace with new filter (from cross reference sheet)
follow directions on filter when installing
Priming
 Using proper container to catch fuel loosen fuel filter
and bump starter, may need to do several times, do not
let pump shut off until system is primed
 When the FASS motor changes tone tighten fuel filter
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How to prime your
FASS system
DDRP/DMAX or FA Series
 Loosen a fitting on the pressure side of the FASS pump
 Using proper container to catch fuel bump the starter,
may need to do several times, do not let pump shut off
until system is primed
 When fuel starts to come out of line re-tighten
Platinum, Titanium or Heavy Duty Series
 Leave water separator tight (Titanium and Heavy Duty)
 Loosen fuel filter so air can be pushed out
 Using proper container to catch fuel bump the starter,
may need to do several times, do not let pump shut off
until system is primed
 When pump motor changes tone and fuel begins to
come out tighten fuel filter
If the FASS pump will not prime proceed to 5 gallon
bucket test to check for possible restrictions
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Trouble shooting
Pump will not turn on when key is on or truck is running
 Refer to electrical section and check relay
 After performing all test call FASS if issue is not fixed
Pump drops fuel pressure under heavy throttle and low fuel levels
 Change your filters
 Refer to the 5 gallon bucket
 After performing all test call FASS if issue is not fixed
Pump sounds like it is shutting ON and OFF or going up and
down in tone
 Change your filters
 Refer to the 5 gallon bucket test
 Refer to electrical section
 After performing all test call FASS if issue is not fixed
Pump is noisy
 Change your filters
 Refer to 5 gallon bucket test
 Refer to electrical section to see if motor is getting to many
volts
 After performing all test call FASS if issue is not fixed
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Technical Q&A
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Where to read fuel pressure? Use the “G” port on the FASS
system or T into the supply line
Noisy or grinding pump? First, check to make all rubber
spacers have been properly installed. It could be cavitation,
restriction or a bad motor. FASS recommends do the bucket
test to see if noise goes away.
I bought an aftermarket filter and the draw tube is to long.
Some aftermarket filter depths are different than our filters.
You can remove a 1/2” off the end of the draw tube and it
should work properly.
I am having priming issues. Suggest cracking the fuel filter
and give the pump power. The pump should change tone
once the system is primed, and at that point you need to
tighten the fuel filter before fuel leaks out the filter. Refer to
“how to prime you FASS.”
My wiring harness is melting/popping fuses. A restriction can
cause increased amperage on the motor, which could cause a
wire to get hotter than normal or pop a fuse. Suggest changing the filter along with doing the bucket test to eliminate all
restrictions which could cause high amperage.
My pump doesn’t turn on and is locked up. First give a direct
12v source to eliminate the harness and/or ECM signal. If the
pump is still locked up suggest checking the gear for any debris that might be stuck in the gear. WARNING: any seal
broken to check for debris in gear without prior FASS approval will void the warranty.
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5 Gallon Bucket
Test
Under the following conditions perform this test
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Low fuel pressure
Lower fuel pressure with different fuel levels in fuel tank
Inconstant fuel pressure
Loss of fuel pressure
Hard starts
Losing prime
Not priming properly
Noisy pump
Fuel pump sounds like it is turning ON and OFF
How to do a 5 gallon bucket test
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Fill a clean 5 gallon bucket 3/4 the way with clean diesel fuel
Pull suction line off fuel tank, this will be the line from the
tank to the “T” port on the FASS pump
Remove the FASS return line at the truck connection
(Platinum, Titanium and Heavy Duty Series)
Put both lines into bucket
Prime the FASS pump
Start truck and check pressure
There only two factors that will affect this test
 The water separator or in line filter
 Suction line
If doing this solves the issue you will need to install a suction
tube or sump to eliminate the issue.
If this does not fix the issue contact a FASS Tech
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Electrical
Many of the FASS units are equipped with a separate wire harness, which has a fuse and/or relay.
To locate the fuse on all units other than DDRP, find where
the red wire from the FASS is connected to the positive side
of the battery or ignition switch.
 The fuse will be between the battery or ignition and relay.
 Remove fuse and inspect, if fuse is blown replace with same
fuse.
 Be sure fuse terminals are clean of corrosion
 Be sure all connections are good and tight and free from corrosion
 Disconnect the FASS pump and using proper tools check for
at least 12volts from the truck to the FASS
How to jump the FASS relay
 Pull relay out of relay socket
 Locate pins 30 and 87
 Using a piece of jumper wire connect terminals 30 and 87,
this will supply a constant 12volts to the pump if the fuse is
good.
Checking trigger wire for relay
 For FASS models equipped with a relay, remove the relay
and locate terminal # 85
 Using a test light bump the starter, if light does not light up
call FASS. Dodge 1998 1/2 and up will stay on for 25 seconds then shut off, Duramax will stay on at all times.
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FASS is blowing
Fuses
All FASS systems will be supplied from the factory with an in
line filter or water separator, a clogged filter can cause the motor on the FASS to over amp and blow a fuse.
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Be sure to check all electrical connections for a loose connection or corroded connection. Replace or repair as needed.
If issue continues proceed to following test.
Replace in line filter or spin on filter to check for possible restrictions. If issue continues proceed to following test.
Once filters are changed refer to 5 Gallon bucket test to
check for restrictions in fuel tank.
If problem continues contact a FASS Tech.
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Hard Starts
(Dodge ‘98.5-’02)
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Answer the following questions
 Did the vehicle start fine without the FASS?
 Do you have high mileage on your VP44?
 Has your VP44 been subjected to 5psi or lower?
 Has your VP44 been subjected to a failing lift pump?
 Does it occur more frequently when conditions are hot?
To test for a cracked diaphragm do the following when you
know the truck will be hard to start
 Unplug the FASS pump
 Start the vehicle as soon as you enter the key into the ignition, shut vehicle down as soon as it starts.
If the vehicle starts without issues there are two options
 Re-wire the FASS– refer to WH-1002 Hard start fix
 Install a Hobbs Oil pressure switch (Closed) into oil filter
and wire ground from FASS harness to oil pressure switch.
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Hard Start Fix
27
Fuel Leak
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Answer the following questions
 Do all male NPT thread fittings have thread tape on
them?
 Are all fitting tight?
 Are all filters tight?
In order to determine where the leak is the unit should be
cleaned of with brake cleaner and allowed to dry.
Then run unit on level ground without movement.
Once it is determined that there is a leak from the FASS contact a FASS Tech.
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