6.7 Cummins Fuel Rail Plug Benefits: Review & Install Guide

What is a fuel rail plug?

A fuel rail plug is designed to provide a connection between the fuel tank and fuel rails that are present on the 6.7 Cummins Engine.

It is made up of high quality steel which ensures its durability. It features O.D. threads that are tapped into the 6.7 Cummins fuel tank fitting o-ring boss.

 It has a sealing/nipple end that can be screwed into the bottom of the engine using an adapter.

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6.7 cummins fuel rail plug benefits – What does a fuel rail plug do?

Fuel Rail Plug to be used when you change fuel injectors or need to remove your fuel rail to do other maintenance on the 6.7 Cummins.

In simple words, a fuel rail plug is a tool that allows you to connect your engine with the fuel tank. By using this tool, you can ensure a proper connection between both systems.

It is a device with a number of benefits. It includes screw dimensions which feature a sealing o-ring nipple end and a fitting/sealing o-ring boss on the fuel tank side.

Sometimes it is necessary to release fuel pressure to remove the fuel rail in order to perform other diagnostics, repair, or replace parts. This plug replaces the stock fuel release valve and will eliminate having to shim it open with washers after you have installed aftermarket ECM tuning that raises the pressure in the fuel rail. Check Which Way Does Coolant Flow Through An Engine?

Provide a better seal that helps prevent leaks and allows your glow plugs to fire at a lower temperature.

What is the purpose of the fuel rail plug on 6.7 Cummins?

The fuel rail plug is set to return fuel from the pressure relief valve and maintain available fuel pressure but can prevent lean blow-by to be detected.

Whether you are racing or cruising, the fuel rail plug is designed to prevent low fuel pressure rail diagnostic trouble codes (DTC P1093), Or  (DTC P0087) that can result when hot leaded fuel is returned from the fuel pressure relief valve by an incompletely closed butterfly in the fuel regulator.

The Cummins 6.7L Race Plug eliminates the ecm reversion safety feature that drops rail pressure if the safety sensor fails. Aftermarket ECM tuning raises the fuel rail pressure and will cause a drop in rail pressure after a rolling period of time which will cause trouble codes.

6 .7 Cummins fuel rail plug review-EVIL ENERGY Diesel Fuel Rail

The EVIL ENERGY Fuel Rail Plug Valve Replacement is your answer to fixing your Dodge Cummins power loss issue.

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It appeals to most diesel engine buyers because it can be installed easily by replacing the stock O-ring on top of the fuel rail with this plug valve that is fitted with a cap on its end cap to ensure that no dirt gets into the injector lines.

 Filled with specially blended blue fluid, this plug valve is compatible with three different kinds of diesel fuels.

It is designed to repair leaking fuel injectors in 2007.5-16 Dodge 6.7L Cummins & in 2004.5-2010 GM 6.6L Duramax diesel engines in trucks, tractors, steerable axels and more.

Eliminates (DTC codes P1093) / (DTC Codes P0087) .

Simply remove the stock diesel rail plugs and install our simple plug-and-go rail assembly complete with new nozzle selector switch housings, new mounting hardware, and easy-to-follow instructions.

Designed to fix leaking and poor performance issues.

For 07.5-16 Dodge 6.7L Cummins & 04.5-10 GM 6.6L Duramax.

6.7 cummins fuel rail plug problems

There is a known issue with the 6.7 Cummins fuel rail plugs that can cause problems when changing injectors or doing general maintenance if not taken care of.

What happens is one of the internal O-Rings in these plugs leaks allowing air to get into the system and pressurize it, causing what looks like an excessively rich condition. This can happen on all Cummins, but it seems to happen more often on the 6.7 since they are prone to oil leaks and this results in these O-Rings to leak.

What should fuel rail pressure be on 6.7 Cummins?

In a 6.7 Cummins, there is about 4000 PSI fuel rail pressure. All diesel engines including 6.7 Cummins have a certain amount of fuel that is injected into the engine cylinders, called a “common rail”.

The fuel injection pressure must be within a very small range otherwise the system could fail. Common rail fuel systems work by using high-pressure pumps to force the diesel fuel into tiny nozzles at extremely high speeds.

Because of the high speed of the fuel, it is important to have a stable pressure. Otherwise turbulence from engine movement could cause the flow of fuel to change or stop.

Where is the fuel rail pressure sensor on a 6.7 Cummins?

The fuel rail pressure sensor is a spring steel diaphragm with a strain gauge attached. You can find the fuel rail pressure sensor of Cummins 6.7L diesel is at the end of the fuel rail.

6.7 Cummins fuel rail plug pros and cons

There are lots of pros of using a fuel rail plug. A Fuel Rail Plug eliminates the OEM Pressure Relief Valve. It provides sufficient tension to the common rail and fuel injector.

Installing the rail plug clears the low rail pressure trouble codes on CP3 fuel injection engines.

A leaking pressure relief valve or rail draining issues can also be diagnosed by the fuel rail plug.

And the only cons would be costing you some bucks for buying it. No other downside for using a fuel rail plug for a 6.7 Cummins.

6.7 Cummins bad fuel rail plug symptoms

There are certain symptoms that show up when your fuel rail plug goes bad.

  1. Difficulty on engine starting.
  2. Less mileage.
  3. Check engine light on.
  4. Bad acceleration.

6.7 Cummins fuel rail plug installation process

1. Find the fuel pressure limiter. It’s located in the intake plenum behind the intake manifold.

2. Clean the fuel rail area and limiting valve thoroughly before installing.

3. Remove the intake connection/EGR valve assembly to access the limiting valve. Loosen the EGR crossover tube clamp on the EGR valve. Loosen the EGR crossover tube’s other end. Remove the intake clamp.

4. Remove the six intake connection bolts. To access the fuel pressure limiting valve, lift the EGR valve/intake connection up and to the side. Remove the old intake gasket.

7. Clean the manifold and the limiting valve area.

8. Clean engine oil the o-ring on the new plug. Clean engine oil threads and sealing surface

9. Tighten the new plug to 70 ft-lbs.

10. Replace the intake gasket. Tighten to 18 ft-lbs

1. Replace EGR crossover tube gaskets To 88 in-lbs on the crossover tube clamps

10. Check for leaks while running.

13. If there are no leaks, the car is ready to go.

How do you shim a fuel rail on a 6.7 Cummins?


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