MaxxForce DT Fuel Injection Code Repair

This is a 2010 MaxxForce DT engine with a fuel injection code. It’s telling us that there’s a problem with the injectors not firing on all cylinders. There are a few possibilities including the high pressure oil pump not delivering enough pressure or a bleed down at the injectors or oil manifold. The harness to the electronic fuel injectors could be at fault with possible continuity issues or the fuel system isn’t delivering enough flow to the injectors.

Using the ServiceMaxx software we can see the desired fuel pressure and high pressure oil readings among other related readings. There are several tests to carry out to check these readings and since we’re just in the beginning stages of working on these engines ourselves it’s all going to be a brand new learning curve. Where have I heard that before?

To start with we removed the valve cover to inspect the top end. The resistance was measured on each injector and one was faulty not matching the other injector readings. The high pressure oil manifold was removed and it was soon discovered an oil pressure sensor and the engine compression brake control were loose in the threads with disintegrated o-rings.

The injector wiring harness had a rubbed through wire and there was also a previous wiring repair made by the Navistar dealer. We are planning on replacing the one injector, injector wiring harness (integral with the valve cover gasket) and replacing all of the high pressure oil manifold seals. I believe this will eliminate the lack of power experienced by the driver.

I’ve seen a lot of performance problems with our DT engines but they were covered by good old warranty. Five years have passed and the 2010 DT diesel engines are in our realm of repair. The common problems have been failed injectors and IPR (injection pressure regulator) / harnesses.

I’ve got technicians in the shop that aren’t afraid to jump on a challenge and figure out a problem. The whole process is interesting from start to finish and common sense will prevail in all cases. The DT diesel engine needs a certain level of fuel pressure and high pressure oil along with a series of sensors and regulators for the injection system to function normally.

Of course healthy injectors help. If the coil on top of the injector head is faulty that will cause a misfire or no injection at all. Extremely high oil pressure to hydraulically actuate the fuel injector is a great concept but any kind of weak spot will cause an engine code once the oil pressure drops to a level not within the specifications. So it’s onward and upward with the troubleshooting and repair of our ‘out of warranty’ DT diesel engines which I will blog about on this site as the problems occur.