6.0 Injector Failure

by Rob Gaskell , First Coast Diesel Performance

Injector Failure

One very common condition is latching of the spool valve, or referred to by Ford as "Sticktion" which is an abbreviation for Static Friction. This condition is caused by oil accumulation on the ends of the spool valves, between the valve and control solenoid, there is a drain hole for this area but at low operating temperatures, oil will latch onto the valve as it is commanded to move and slow it's movement, causing a missed or late injection event, poor cold start and poor performance at low engine operating temperatures. As the spool valve and it's bore wear, the amount of oil which can accumulate in this area will increase and exacerbate the issue.

A certain amount of wear as injectors age is normal. Extended service intervals and coolant contamination of the engine oil will both cause more rapid wear. Coolant from failed EGR coolers has been proven to wipe out an entire set of injectors rapidly, not to mention the wear and damage it will cause to other components which require engine oil lubrication. Ford sought a fix due to the high number of injector warranty replacements. The first attempt was to cycle the injector spool valves for a short period after engine shut down. The purpose was to purge any excess oil from this area, but this was found to be ineffective due to oil accumulation from leakage after a cold start up. The next attempt was a developement of the inductive heating flash. this software applies a current to the close coil which creates a rapid heating of the coil and surrounding components which allows oil to drain away much faster, eliminating spool valve latching. Inductive heating solves nearly every case of cold start performance issues, and extends the service life of an injector. Injector harness issues have been quite common. Chafing of the harness and eventual breakage of wires can cause drivability issues such as misfire and can set circuit DTC's in the PCM memory.

FICM (fuel injection control module)

Fuel injection control module failures have been common. We have found a direct link between FICM failure issues and battery/charging system and connection issues. Low voltage will cause overheating of the circuit boards , DC to DC converters(these step up voltage from B+ to 48 volts) which leads to failure. It is important to quickly address any charging system issues. I have also read and heard that the inductive heating flash can cause FICM failure due to the amount of extra current during inductive heating. I have seen no evidence to support this claim.

Air in fuel or fuel interruption (low fuel volume)

Air in fuel can be caused by failed injector combustion sealing. Failure of the copper combustion seal or a damaged injector cup will allow combustion to pass into the fuel system. In the early stages it will cause poor engine performance and a noticeable lack of power. In the later stages it will cause cylinder misfire that will get worse as the engine runs, in a matter of a few seconds. At this stage the truck is generally not drivable and will hardly run. Combustion seal failure usually shows up after an injector replacement when the injector hold down bolts have not been properly torqued to specification. This failure will also cause damage to the injector cup and injector by subjecting both components to combustion heat. You will generally find a discoloration of the injector body which sits in the injector cup, and pitting in the cup sealing surface, in which case, both components will need to be replaced.

Low fuel volume or fuel interruption can be caused by retricted filters, air being drawn into supply system between the tank and lift pump, a restriced manifold assembly on the HFCM (horizontally mounted fuel conditioning module).

Low fuel volume will cause damage to the injector in a very short period of time. Fuel provides a cushion for the amplifier piston within the injector. Loss of this cushion will cause this piston to bottom out and eventually stick in the down position. This in turn will not allow the oil to escape before the next injection event. This will lead to breakage of the stator (the top part of the injector) retaining bolts and destroy the injector. Both air in fuel and low volume will cause internal damage to the injectors fuel delivery components, pintle, nozzle and other parts that need fuel for lubrication. As you can see, many of the 6.0L Powerstroke Diesel injector issues are preventable by performing regular maintenance.

If you have any questions or would like to comment, call, text or email 503-982-5516, robsr@fleetservicenorthwest.com

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