6.0 POWERSTROKE FUEL PRESSURE TESTING AND TIPS

Low fuel pressure will damage injectors
6.0 POWERSTROKE FUEL PRESSURE
TESTING AND TIPS
WHAT CAUSES INJECTOR FAILURE
This chart is from FORD. As you can see, we need to do our part to ensure
the customer gets good service without un-needed repairs. Many repeat
repairs can be attributed to improper filter replacement or service.
FUEL SYSTEM DIAGNOSTICS
Check fuel pressure at
the test port in the
secondary filter housing
Check regulator and return lines for restriction
Flush system ; Replace fuel and filters
Sample fuel
Bad fuel
Inspect replace fuel filters and retest
Amp ramp and voltage drop fuel pump and wires
Check for fuel inlet restriction.
Check pressure regulator.
Repair wiring or replace fuel pump
Repair restriction or pressure regulator
FUEL TEST PORT
´
If fuel pressure drops
below 38 psi under heavy
load, there is a fuel
delivery concern. Always
verify fuel pressure under
load.
Fuel pressure test port
4
E series back of each head
F series
FUEL PUMP AMPERAGE
D/C COUPLE
A/C COUPLING
5
PRIMARY FILTER
´
´
´
Primary filter removed
10 micron filter
After fuel is drawn from
tank and conditioned it
flows to secondary filter
6
SECONDARY AND PRIMARY FUEL FILTERS
7
SECONDARY FILTER
´
´
´
´
Four micron filter
Mounted next to oil filter
on top of engine
Secondary filter also
houses regulator valve
Returning excess fuel to
return line
also incorporates an
orifice at the top of
housing to bleed any air
out of fuel
8
INLET RESTRICTION TEST
´
´
´
´
´
Low fuel pressure and
volume could be caused by
tank restriction
Check inlet side of
horizontal fuel conditioning
module for a vacuum
Tee in vacuum gauge with
fuel inlet
Five – six inches of vacuum
maximum
Higher than five or six
inches of vacuum check fuel
inlet line and tank
9
FUEL AERATION TEST
´
´
´
Remove return line at
horizontal fuel control
module
Install clear hose on
return line and run into
clean container
Operate engine at WOT
for a short time and
watch for bubbles in
clear hose
10
WATER DRAIN
´
´
Located on the side of
fuel conditioning
module located on
drivers side frame rail
There is a casting plug
on Fuel housing has to
be removed to drain
water
11
MULTIPLE CYLINDERS SAME SIDE LOW ON
POWER?
The fuel supply line on the front of both heads has a banjo bolt with a flow valve in it. This
valve can restrict with contaminants. All 4 cylinders on the bank will have low power or
misfire concerns. To verify the concern, check fuel pressure at the back of the head
involved.
BAD COMPRESSION RING
If this concern has existed for a period of time, keep in mind all 4 injectors on that side of the engine should be replaced. Air can be compressed so the injector gets pounded and does not have the amount of fuel needed to lubricate and remove heat.
Copper sealing rings must be replaced any time the injector is removed. They are one time seals only.
13
TIP-PwrBal. Test can find
the worst of the bunch for
us to
Start with
Upper fuel o‐ring
Fuel inlet
Lower fuel o‐ring
Compression
POOR RUN FUEL PRESSURE OK
Multiple cylinder misfire can be caused by one injector allowing compression pressure to bypass the copper injector compression seal and fuel o‐ring causing severe aeration of the fuel.
To diagnose this concern just remove the secondary fuel filter. Remove fuel pump voltage feed or fuel pump relay. Remove the cam or crank sensor wire , crank the engine and look for air You can remove the left or right fuel line to determine what bank bubbles in the fuel.
has the concern. But keep in mind it will be the one with the misfires.
FUEL LEAKS INTO THE OIL?
Bolts can break and cause a fuel leak.
Oil leak
Always check the oil level before you service a 6.0 power‐stroke. If the oil level is too high, suspect fuel leaking into it. Pull the drain plug until the oil stops leaking. Run the fuel pump. If fuel leaks out of the oil drain, you found a problem. Block the fuel flow to one head to isolate what bank the leak is on. Fuel contamination can hurt the turbo shaft and bearings.
FUEL INLET RESTRICTION OR AIR LEAK
Install a clear looped hose in the fuel return line. Hold the engine RPM at a steady 2000. Verify there are no air bubbles.
Insert a vacuum gauge in the line between the tank and fuel pump inlet. If fuel pressure was low, ensure vacuum stays under 3 inches at idle and does not exceed 7 inches under high RPM and load. If vacuum is high, check for a restricted fuel pickup or line.
HFC MODULE NEW DESIGN
If you replace the HFC module, you make get a newer design that no longer has the fuel heater. There is a molded hole where the heater went. There is also a replacement harness that removes the electrical plug.
NEW HARNESS – HAS 3 CONNECTORS
18
OLD HARNESS HAD 4 CONNECTORS
19