2015-2016 Ford 6.7L Powerstroke Fuel Lines

Fuel lines on the 2015-2016 Ford 6.7L Powerstroke

There are three circuits to think about. The low-pressure supply runs from the tank through the frame-mounted Diesel Fuel Conditioning Module, with its electric lift pump, 10-micron filter and water separator, up to the 4-micron secondary filter on the driver side of the engine and into the CP4.2. The high-pressure side runs from the pump to the two common rails, which operate at up to 30,000 psi on 2011-2019 engines, and from the rails to each piezo injector through individual injection lines. Then there is the return circuit from the rails and injectors. Ford used OE-style quick-connects on the factory supply lines. The rest of this engine's parts are on the Powerstroke hub.

What fails and why

Two problems drive most line work on this truck. The first is CP4.2 contamination. When the pump's roller followers skate on the cam, they shed fine metal that passes the metering-valve screen and spreads into the injectors, rails, lines, lift pump and tank. After a failure, the lines and rails must be replaced or cleaned along with everything else in that path. The second is leaks on the return side. The plastic injector-return fitting is a documented leak point, and like the plastic engine-mounted filter housing it can crack and spray fuel onto the exhaust in the engine valley, which is a fire hazard. Signs include a diesel smell, fuel on top of the engine and drips near the driver-side filter.

Stock replacement vs. upgrade

For a factory-spec repair, OE-style injection line and O-ring kits restore the original layout, and a contamination kit covers the post-failure job in one order. For the return-fitting leak, a billet replacement fitting is the documented fix. If you are adding protection or filtration to the supply side, choose parts that plug into the factory quick-connects instead of compression fittings, which can shed debris into the fuel; the S&S CP4 kit is built that way. Universal oversized high-pressure lines and AN fittings are for custom fuel builds and need a plan before you buy.

What we carry

Alliant Power AP0087 and AP0088 injection line and O-ring kits, plus Alliant fuel contamination kits AP57001, AP57001NP (no pump) and AP57010 for cab and chassis trucks. XDP XD515 and XD612 (no pump) stock-replacement contamination kits, and the SPE Motorsport DKT151667 kit. The Mahle GS33712 fuel rail supply line. The Fleece Performance Engineering FPE-FMC-FF-RLK-1116 injector return line repair fitting. A BD Diesel 1050165 fuel injector line set. Dynomite Diesel universal oversized high-pressure injection lines in multiple lengths. Exergy Performance M14x1.5 three-way T fittings, plug-and-nut rail caps, and M12x1.5 to -6AN and -8AN high-flow supply fittings.

Fitment notes

The Alliant line kits and the Mahle supply line are listed for 2011-2019 6.7L trucks, which covers your 2015-2016, and the BD line set is listed for 2011-2021. The contamination kits are model-year specific: AP57001, XD515 and DKT151667 are listed for 2015-2016, and AP57010 is the cab and chassis version. The Exergy high-flow supply fittings are titled as CP3 fittings, so confirm they suit your build before ordering. AP0087 and AP0088 are different kits; check each listing for which lines it covers. When in doubt, verify by VIN.

Frequently asked questions

Do I have to replace the fuel lines after a CP4 failure?

Plan on it. The guidance after a CP4.2 failure is that the lines and rails must be replaced or cleaned along with the injectors, pump, lift pump, filters and tank. Reusing a contaminated line puts that metal right back in front of new parts. A contamination kit is the simplest way to cover the whole job.

Why is there fuel on top of my 6.7L Powerstroke?

The two documented culprits are the plastic engine-mounted fuel filter housing and the plastic injector-return fitting, both of which can crack and spray fuel onto the exhaust in the engine valley. That is a fire hazard, so do not ignore a diesel smell. Billet replacement fittings are the documented fix for the return side, and the Fleece injector return line repair fitting in this collection is made for that spot.

What is the difference between a contamination kit with and without a pump?

The no-pump versions, Alliant AP57001NP and XDP XD612, leave the injection pump out of the box. They suit owners who are sourcing the pump separately, for example someone moving to the S&S DCR conversion instead of another CP4.2. The other kits include a pump.

Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.