6.0 POWERSTROKE FUEL PRESSURE TESTING AND TIPS

Low fuel pressure will damage injectors

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

Sample fuelFlush system ; Replace fuel and filters

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

Bad fuel

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.

4

Fuel pressure test port F series

E series back of each head

FUEL PUMP AMPERAGE

5

D/C COUPLE

A/C COUPLING

PRIMARY FILTER

Primary filter removed10 micron filterAfter fuel is drawn from tank and conditioned it flows to secondary filter

6

SECONDARY AND PRIMARY FUEL FILTERS

7

SECONDARY FILTER

Four micron filterMounted next to oil filter on top of engineSecondary filter also houses regulator valve Returning excess fuel to return linealso 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 restrictionCheck inlet side of horizontal fuel conditioning module for a vacuumTee in vacuum gauge with fuel inlet Five – six inches of vacuum maximumHigher than five or six inches of vacuum check fuel inlet line and tank

9

FUEL AERATION TEST

Remove return line at horizontal fuel control moduleInstall clear hose on return line and run into clean containerOperate 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 railThere 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

13

Upper fuel o‐ring

Fuel inlet

Lower fuel o‐ring

Compression

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.

TIP-PwrBal. Test can find the worst of the bunch for us to Start with

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 bubbles in the fuel.

You can remove the left or right fuel line to determine what bank has the concern. But keep in mind it will be the one with the misfires.

FUEL LEAKS INTO THE OIL?

Oil leak

Bolts can break and cause a fuel 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