Powerstroke diesel engines have gone in to Ford’s Super Duty trucks, E-Series vans and the Excursion since the mid 1990’s. Initially produced by Navistar, (formerly International Truck & Engine,) Ford took production in-house in 2011, today building the fourth generation in Mexico.
Known for good torque and horsepower, the Powerstroke has been a resounding success. Unfortunately it’s also known to have a few weaknesses, one of which is the injector harness.
The injector harness routes electrical signals to the injectors, ensuring fuel is delivered at the right point in the compression stroke. When those signals don’t get through the affected injector(s) won’t operate and the engine runs unevenly, or not at all. Injector harness problems have been widely reported with the 7.3 and the 6.0 liter Powerstroke engines.
The “Check Engine” light will be illuminated and the trouble code is “P1316”, meaning a fault with the injector driver module (IDM). A “Buzz” test will check all eight injectors are working, but not many home mechanics are equipped to do this.
The alternative is determine which injectors aren’t operating, (check the exhaust manifold temperatures,) and examine the harness connection supplying those cylinders. Often the connector will be found to have separated, although sometimes a poor connection has caused heating that burns or melts the connector block.
Here the problem is the harness routing. Over time it chafes, eventually leading to failure. Complicating matters, the damage is sometimes internal and not visible to the naked eye. Symptoms will usually be one or more injectors not working (though they will be on the same bank,) or random engine shut-offs due to the harness grounding internally.
While it’s possible to buy individual harness components it’s easier to buy a complete kit including valve cover gasket.