Ford 6.0 Diesel

The 6.0 Injector

There are three basic problems that happen with these injectors. The 6.0 injector is prone to failure from dirty engine oil. If you own one of these trucks be sure to keep up on regular oil changes. The other injector problem is from what is called stiction. The injectors on the 6.0 have two spool valves on top of the injector. One opens the injector to let high pressure oil in to fire the injector and the other closes it. After time and use, these spool valves will start to weaken. Especially when the engine and oil is cold, weak spool valves cannot pull the valve open and closed fast enough to operate without severe missing. This is what causes the common complaint of terrible starts and cold running until operating temperature comes up to normal. When the oil and engine temp reaches normal the truck will run like normal with no performance problems. Besides keeping the oil clean, fuel is the second major issue that affects 6.0L injectors. Poor quality fuel containing dirt and water is a recipe for 6.0L injector disaster. Additionally, because fuel in the injector is used to provide a cushioning action for the internal valving of the injector, low fuel pressure will severely harm the injectors. Clogged fuel filters caused by neglected maintenance intervals are a common reason for injector damage. We recommend that fuel filters be serviced at 10,000 mile intervals. Low pressure caused by a failing fuel pump can cause repeat injector failure. ALWAYS check fuel pressure after installing new injectors – it should be between 45 and 55 PSI and should not drop below this spec under load. Running a 6.0L Powerstroke out of fuel should be avoided at extreme cost. If you think you are going to run out of fuel, shut the truck off, and walk – it may save you $2,500. Again, good diagnostics are going to be needed here to figure out whether you have bad injectors, bad batteries, bad glow plugs, a bad ficm or something else that is causing your hard cold starts.

What are some common symptoms of injector failure?

Hard Starting (especially w/ cold engine)
Excessive Smoke
Rough Running
Low Power
Bucking / Jerking

How do 6.0L Injectors Work?

The Ford Powerstroke 6.0L injector is a HEUI Injector (‘HEUI’ stands for Hydraulic Electronic Unit Injection). A high pressure oil pump on the engine uses the engine oil to develop up to 3,800 PSI of oil pressure. This high pressure oil is routed to the injectors where pressure multiplication occurs at a ratio of 7:1 generating actual fuel injection pressures over 26,000 PSI. The fuel injectors are controlled by a control module called FICM which produces 48 volt outputs to solenoids on each injector which ultimately determines the duration and timing of fuel injection.

What causes the injectors to fail?

We have seen early trucks require a complete set of eight new injectors after enduring fuel starvation. Later build trucks incorporate a PCM strategy which limits pressure to prevent injector damage during a low fuel condition, but we strongly recommend that testing the effectiveness of this strategy be avoided.

Tips for diagnosing faulty 6.0L Fuel injectors:

Please note that we cannot begin to cover all the diagnostic strategies and possible failures of the 6.0L injection system here. These are just some useful tips we have found. The starting point is always to check for cylinder contribution codes using a Ford IDS / WDS or similar scan tool. Follow this step with a cylinder balance test which creates a visual display of crankshaft RPM variation allowing you to see which cylinder(s) are weak.

  1. The starting point for 6.0L injector diagnosis is often the scan tool. A Ford IDS or quality aftermarket scan tool may be used. The first step is to check for codes. Two types of codes may be found – These are cylinder contribution codes, and electrical fault codes. NOTE: Cylinders numbered 2, 4, 6 and 8 are on the driver’s side of the engine. Cylinders numbered 1, 3, 5, and 7 are on the passenger’s side. Higher numbers are toward the rear.
  2. If electrical fault codes are present, do NOT assume that the injector is at fault. Concerns with the fuel injection wiring harness are very common and may cause extremely troubling intermittent conditions. Close visual inspection of the harness running between the FICM (fuel injection control module) and the injectors, especially where it rubs against the valve covers, intake manifold, and intake manifold mounting bolts is very important. Chafing of the insulation is very common in these areas. Often replacement of an injector or FICM will appear to correct a problem temporarily, but the problem will reappear as the wire resumes its original position.
  3. Cylinder fault codes (without electrical codes) also do not automatically indicate that the injector is at fault. Keep in mind that there are other reasons a given cylinder may not contribute it’s fair share to the engine’s operation. Many better scan tools will allow a relative compression test to be performed from the comfort of the driver’s seat by comparing the draw of the starter (and the corresponding drop in battery voltage) during cranking as each cylinder goes through the compression stroke. We have seen many cylinder contribution codes caused by simple and easily repaired upper valve train problems such as broken rocker arm bridges or bent push rods.
  4. In order for 6.0L injectors to operate correctly, they must have sufficient quantity and pressure of good clean engine oil and fuel. Before condemning injectors, always check engine oil level and change it if it has been neglected. Taking a fuel sample and inspecting it for any contamination, as well as measuring fuel pressure (there is a plug on the secondary fuel filter housing for this purpose) are highly recommended.
  5. Fuel injection control module issues are another common cause of 6.0L fuel injection concerns. If FICM codes, multiple fuel injector circuit low codes, or code U0105 are present then pursue FICM diagnosis and possible replacement before faulting the injectors.
  6. Combustion gas (air) entering 6.0L injectors and fuel rails is a common problem and will cause a random misfire not only on the cylinder the problem originated on, but on other cylinders as well once air enters into the fuel rail. If multiple misfires are present, predominately on one bank, suspect this fault. By far the most common route for combustion gas to enter the system is via a leak past the copper gasket at the tip of the injector. After leaking past the tip gasket, gasses under high pressure will blow past the lower o-ring on the outside of the injector and allow air into the fuel system. As the failure progresses over time, fuel under pressure will eventually find its way into the cylinder following the reverse path as the combustion gasses. This will at first result in massive quantities of white smoke, and shortly thereafter in a hydro-locked engine.

Follow the following steps to find which cylinder is causing the problem:

  • Remove the fuel pump and fuel injection control module relays
  • Remove the fuel lines that run from the fuel filter housing to each cylinder head.
  • Put a balloon over the end of each of the fuel lines coming from the head and use a rubber band or zip tie to seal the balloon tightly to the line.
  • Have a helper crank the engine and watch the balloons closely for any sign of pulsing which indicates compression leakage. This will allow you to determine which bank the problem is on.
  • Remove all but one glow plug from the bank with the problem. (Removing the glow plugs relieves compression in the cylinder.) Crank the engine and move the glow plug from cylinder to cylinder to find which one is affected.
  • Remove affected injectors, and carefully observe the copper gasket at the tip. The washer should display an even circular crush pattern and there should be no carbon above the washer. If in doubt, replace the washer and try again. Beware of missing washers, or possible mistaken installation of two washers.
  • Alternate methods of detecting combustion gas leaks (“Bubble test”):
    • Remove the top cover of the secondary fuel filter and observe for bubbles rising in the filter housing while cranking (with FICM and fuel pump relays removed!)

Additional Tips:

  • Before beginning any diagnosis or parts replacement, always determine if your truck’s PCM and FICM have been updated to the latest software. Several program updates are available to correct hard cold start, no cold start, white smoke, and poor cold operation issues by energizing the injector coils using an inductive heating strategy to prevent the injector spool valves from sticking until the engine has reached normal operating temperature. Correct up to date software is critical to satisfactory 6.0L operation.
  • Any time a 6.0L develops a stalling problem or a miss, check the problem out right away to prevent further damage!
  • The word ‘Stiction’ combination of the words ‘sticky’ and ‘friction’. Stiction affects the operation of the injector’s spool valve and will result in rough engine operation especially when the engine is first started. Maintaining clean engine oil of the proper type and viscosity at all times will prevent contaminants from developing inside the injector and causing stiction.

Replacement Instructions:

  • 6.0L injector replacement is not extremely difficult and does not usually require special tools, but is only recommended for those with at least a minimum of mechanical training. It does require strict attention to the details mentioned below – Please read the following to avoid common errors.
  • EVERY time an injector is removed / replaced the copper tip washer and o-rings MUST be replaced. Be sure not to install two copper washers (Ensure the old one did not stay in the head.) CAUTION: The seal between the tip of the injector (where the copper tip washer contacts the head) is very critical. Make sure this area is clean, that only one washer is installed, and that the injector retaining bolt is properly torqued. If a leak occurs in this area, combustion gases will pass up the side of the injector and burn out the lower injector o-ring. This, in turn, will allow fuel into the cylinder which, in a worst-case scenario, can cause hydro-locking and engine damage. This is NOT a warrantable condition.
  • Book time for a single injector replacement on a pickup is 1.6 hours with additional injectors on that side paying 0.2 hours each. Vans are much more difficult and replacing an entire set can consume 8 hours.
  • Owners of 2004.5 and newer trucks should consider replacing the standpipe and dummy plug seals while the valve covers are off – leaks at these locations are a common cause of hard hot starting. (See related items below.)
  • Torque on the injector retaining bolt is very critical! Early build trucks with a T40 retaining bolt require 24ft-lbs. Later trucks with T45 retaining bolt require 26 ft-lbs.
  • ‘Quick’ Removal /Installation Guide (NOT a substitute for your manual):

    • Remove valve cover
    • Early build trucks (before 2004) will have a tubular style oil rail that requires a special tool to disconnect the supply line from the oil rail (such as OTC 6594). In most cases it is not actually necessary to disconnect the rail. You can gently move it around to clear the injector as needed.
    • Later build trucks require removal of the high pressure oil standpipe that delivers oil to the ‘wavy’ design oil rail. The standpipes require an allen wrench for removal.
    • Remove the 8 bolts that retain the high pressure oil rail and pull straight up to remove.
    • Inspect the oil inlet area of the injectors for metal shavings which indicate high pressure oil pump failure in process. If shavings are found, the high pressure oil pump must be replaced and the system flushed or failure of the new injectors will occur in very short time. Also note that if the tops of any injectors are broken off the cause is insufficient fuel pressure or air in the fuel and that this issue must be corrected to prevent short-term reoccurrence.
    • After disconnecting the electrical connector, use a 19mm 12 point chrome socket to push the remaining portion of the connector body out of the rocker housing.
    • Loosen the torx bolt that holds the injector in place. Be sure to use a medium length torx bit to avoid making contact with the solenoid on the injector and breaking it off. Unscrewing the injector hold down bolt will unseat the injector – do not use air tools, and do not pry on the injector coils which will damage them. Also, be sure the copper tip gasket does not stay in the head.
    • Before installing the injector be sure that the injector cup in the cylinder head is perfectly clean, particularly the tip gasket and o-ring contact areas. Lubricate the o-rings with engine oil before installation.
    • Before tightening the injector hold down bolt, clean any oil out of the bolt hole. Oil remaining in the bolt hole will cause the bolt to tighten before the injector is seated resulting in catastrophic failure. Remember that injector hold down bolt torque is very critical.
    • Lubricate the inlet tubes on the high pressure oil rail with engine oil and seat the rail by hand before tightening bolts. CAUTION: Not seating the oil rail properly when installing the rail back on the injectors is the #1 installation error. If the rail is not installed with finesse, the injector inlet seal will be damaged and a high pressure oil leak will result, ultimately causing a hard hot start condition. Seating the rail properly is not difficult, just be careful to work it into the injectors slowly and keep it square so the seals are not damaged. Do not use force!
    • Changing the engine oil, oil filter, and primary and secondary fuel filters is recommended.
    • Be aware that the engine will be somewhat difficult to start since air has been introduced into the oil and fuel systems. Upon starting, the engine will run rough for some time until all of the air has purged.



714 Harkrider St
Conway, AR 72032