What Causes Diesel Injector Leak Back?

Many important components make up common rail injectors. Another typical problem caused by contamination or wear and tear over time is that the pilot valve in your common rail injector wears out, causing your injector to back-leak, causing your vehicle to stall, run rough, lack power, and eventually stop running.

How do I stop my diesel injectors from leaking?

If there is a leak, turn off the car right away. Start the automobile after removing the fuel pump fuse and wrapping the leaking injector with a shop towel to absorb up the gasoline. Allow the vehicle to continue to run until it stalls. This procedure relieves the fuel rail’s pressure, allowing the rail to be safely removed.

What happens when diesel injectors leak?

A basic grasp of the fuel injection system is essential to understand why leaky fuel injectors are problematic and harmful. Manifold fuel injection and direct fuel injection are the two types of fuel injection systems. A gasoline pump, fuel pressure regulator, fuel lines, fuel filter, fuel rail, fuel injectors, and the engine control unit or engine management system make up the basic manifold fuel injection system. Side feed and top feed fuel injectors are used in manifold fuel injection systems, which run at roughly 45 Psi (pounds per square inch) on average.

When the engine is started for the first time on any given day, the fuel rail, which is part of the fuel injection system, is pressurized to the operational pressure of the fuel injection system by the fuel pump, which is controlled by the engine management system. Throughout the driving or running period, this operating pressure is maintained. External fuel injector leaks, such as a fractured fuel injector body or worn-out fuel injector O-rings, might result in an engine fire at any time.

Leaking fuel injectors can cause Oil Thinning

When the engine is turned off, the fuel pressure should be kept at or just below operational pressure for a long time. Fuel will escape into the intake manifold due to pintle, ball, or disc seat leaks, as well as the bottom O-ring leak on a side feed injector. Fuel will flow down from the manifold to the intake valves. When an intake valve is open, fuel enters the cylinder, leaks past the rings, and finally mixes with the engine oil.

Engine bearing damage and burned cylinder side walls can result from oil thinning. It can even cause an explosion inside the engine in extreme situations. Hydro lock has been reported as a result of leaking fuel injectors because so much fuel gathered on top of the piston that when the engine was turned over, it couldn’t compress the liquid in the cylinder. To name a few effects, hydralock can result in bent connecting rods, fractured pistons, and blown head gaskets. All of the repairs were extremely costly.

Leaking fuel injector can be the cause of hard starting

The most common reason of problematic or difficult to start engines, especially when they are heated, is a leaking fuel injector or injectors. This is because the fuel rail pressure has reduced, allowing fuel to flow into the manifold, flooding the spark plugs.

O-rings are used to seal the fuel injector and the fuel rail in both top feed and side fuel injectors. Fuel injector O-rings, especially on older automobiles, can harden and become brittle over time. This can result in both external and internal gasoline leaks and should be addressed right away.

The vehicle should not be driven if a fuel leak is observable from any of the fuel injection components. The issue should be resolved as soon as possible. If you suspect your engine’s fuel injectors are leaking, call your mechanic right away.

What causes a fuel injector to leak?

Clogs and leakage are two issues that plague fuel injectors. As previously stated, clogs occur when carbon deposits form on the injector nozzles, causing them to become stuck in either the open or closed position. O-ring failure between the injectors and the fuel rails is the most common cause of leaks. Engine heat can cause the o-rings to become brittle and shatter, resulting in a fuel injector leak.

Can you drive with a leaking fuel injector?

-If your fuel injectors are dirty, the automobile will merely misfire since they can still transfer fuel in a gaseous form but not enough for the engine.

– If your fuel injectors are jammed and won’t open to send fuel into the intake tract, your automobile won’t start at all.

– If your fuel injectors are leaking, which means they are dripping liquid fuel rather than gaseous fuel, you should avoid driving until the problem is resolved. Otherwise, a hydrostatic lock could occur, causing the piston to break, connecting rods to flex or shatter, and valves to break or bend. Particularly in an interference engine.

– If your fuel injector gets caught on the nozzle owing to a defective control, it could produce a hydrostatic lock, as the nozzles would pour more fuel than needed, flooding the system and contaminating the spark plugs.

Because the signs we outlined above indicate that it will be highly harmful to your engine in some situations, replacing a fuel injector is far easier and less expensive than replacing a whole engine. If you still want to drive despite all of this, be prepared to face the following consequences:

What is the most common cause of injector failure?

Fuel injectors are nothing more than solenoids, which are cylindrical coils of wire that act as magnets and transport an electrical current and actuate pistons very quickly as part of the engine’s fuel delivery system. It takes a high-pressure mist of gasoline and sprays it into the engine, all under the direction of the car’s internal computer. The computer controls the amount of gasoline dispersed as well as the precise time. One fuel injector per cylinder is standard on most vehicles and light trucks with internal combustion engines. The injectors could fire millions of times over the duration of the vehicle’s life!

Previously, automobiles were built with fuel sprayed into the upper intake manifold to mix with air before being ignited in the combustion chamber. Manufacturers eventually switched to one injector per cylinder fuel injection, where fuel is delivered into the lower intake manifold right behind the intake valve. Many automakers have switched to direct injection in recent years. Instead than using the intake manifold, direct injection injects fuel directly into each cylinder. Direct fuel injection systems emit less pollutants, are more powerful, and efficiently deliver gasoline. Direct injection, on the other hand, is more expensive due to more expensive parts and higher fuel consumption. As a result, while the car uses fuel more effectively, it still consumes a significant quantity.

What are the Signs of a Bad Fuel Injector?

The development of impurities such as carbon causes fuel injectors to malfunction. Carbon buildup might result in a clogged or partially clogged injector, preventing it from fully closing. This causes a leak, which causes a misfire. Dry, damaged rubber seals or flaws within the injector itself can cause fuel injectors to leak outside. Electrical components of the injector are particularly susceptible to aging, heat, and moisture damage. Failure manifests itself in the following ways:

  • Misfires caused by a lack of fuel – Misfires are perceptible occurrences that happen while the engine is operating and are usually noticed by a difference in performance or a minor popping sound. The larger the engine, though, the less likely you are to experience a misfire.
  • Lack of power – The engine is unable to provide enough power to keep running.
  • Poor fuel efficiency — Fuel is wasted due to leakage, over-supply, or inability to produce a correct spray pattern for burning.
  • Check engine light on – The check engine light can be triggered by too much or too little fuel provided to the engine.
  • Having trouble starting – The engine is receiving too much or too little fuel. This can also cause the engine to stall or prevent it from starting at all.
  • Fuel Odor — If an injector is leaking, you may notice a gasoline odor while driving.

Any time your car develops a leak, especially a fuel leak, it should be evaluated by a professional as soon as possible. Fuel and fumes leaking from the vehicle’s hood could ignite and cause a fire. A clogged injector does not endanger the vehicle’s safety, but it does starve it of fuel, leading it to operate poorly. Long-term fuel deprivation can cause internal engine damage as well as catalytic converter damage. It’s possible to inspect and test fuel injectors to see whether they need to be changed or cleaned.

How often should diesel injectors be replaced?

The fuel injection system is an important part of any diesel engine. The fuel is pressurized and injected into compressed air in the combustion chamber via this system. Feeding fuel to the injectors, regulating the fuel supply, modifying the injection time, and atomizing the fuel are all operations of a fuel injection system.

The proper amount of fuel, at the right time, in the right condition for combustion, must be delivered.

Fuel injectors help enhance fuel efficiency, reduce the need for fuel system maintenance, and keep emissions cleaner. A diesel fuel injector has an average lifespan of 100,000 kilometers. The nozzle and the injector body are the two primary elements of a standard fuel injector. If either of these components becomes clogged or destroyed, the vehicle’s overall performance is jeopardized.

  • Uneven idling or difficulty starting the car. The engine cranks, but it won’t start unless you crank it hard enough. On idle, the engine uses a variety of rev levels.
  • Misfire. A full diagnostic of a vehicle that is misfiring on ignition entails determining which component of the combustion process is missing. This is caused by either a lack of fuel injection or a lack of combustion chamber heat in a diesel engine. One of the cylinders’ fuel charge fails to ignite, or the fuel supply to the ignition system is insufficient.
  • There’s a strong odor of gasoline. The scent of diesel within the cabin indicates that there is a leak. This could be caused by a malfunctioning injector that allows fuel to leak out while it isn’t in use.
  • Emissions are filthy. Filters that are clogged and deposits on injectors create an uneven or partial fuel burn, resulting in a polluted environment around the exhaust and the discharge of white smoke from the exhaust pipe.
  • Fuel consumption has increased, while miles per gallon has decreased. Faulty injectors waste more fuel and have a direct impact on the performance and efficiency of your vehicle.

Clean fuel injectors are essential for your diesel engine to run at its best. Any of the following signs could suggest an issue with your fuel injectors, which should not be overlooked. Injectors that are unclean, clogged, or leaky are examples of this. If you’ve driven your car for more than 100,000 miles without replacing the fuel injectors, it’s time to have them looked at by a specialist.

How much should injectors leak off?

A set of measuring bottles, 2 meters of 3.2mm internal diameter tubing, a set of leak-off connections, and four plugs with 7 mm entrance holes are required to complete a leak-off test.

I used four hair color bottles that I found on eBay at a very low price. The 3.2 mm tubing, like the second-hand leak-off connectors, was purchased on eBay. The four plugs are easily created by drilling a blind hole in any hard material with a 7 mm drill. The depth isn’t crucial, but it must allow the small O ring to enter. Hard wood, plastic, or metal, like in my case, could be used.

The Ford leak-off pipes aren’t quite what they seem to be. The rigidity of the pipes is due to the black rubber outer covering a strong plastic inner tube. I didn’t think I’d be able to remove the car’s leak-off pipes from the connections, so I acquired a junk set and cut the pipes off of them before removing the outer rubber covering. In the shot below, you can see the inner hard plastic tube inside my translucent plastic tubing. (Alternatively, a 7mm OD hose, such as 3.2x7mm silicone vacuum pipe, can be plugged into the injector holes directly.)

Unplug the car’s leak-off connectors and insert your plugs (in my instance, the gleaming metal cylinder) into each one. (Alternatively, the leak-off connector can be plugged using cocktail sticks and a couple of turns of PTFE tape.) If these pipes are not plugged, air will be pulled into the high-pressure injection pump, causing problems with starting the engine for the test.

The tapered nozzles on the hair color bottles can be cut off and the transparent plastic tubing pushed onto them. It’s a good idea to mount the bottles on a metal strip so that the results don’t get mixed up.

According to Delphi, the fuel temperature should be at least 50 degrees Celsius for this test.

In this test, good injectors should not leak more than 25ml. Looking at my results from left to right, the first one is a factory-installed injector that gives a decent 20ml result. The second is a Swadincote Diesel injector that has recently been reconditioned and barely passes the 25ml test. The next two show 30ml and 28ml fail results, respectively.

Injectors might fail in one of two ways. The Leak-Off Test above is used to determine how much water is leaking through the valve. Due to excessive leakage, the injection pump is unable to produce or maintain the pressure in the common rail that the ECU requires. When this happens, the ECU will limit or shut down the engine, and a DTC error such as P1211 will be recorded, indicating a failure to attain proper pressure.

The other type of leaking is that which occurs after the needle has been removed. Fuel seeps into the cylinder when it shouldn’t in this scenario. This leakage has the consequence of causing firing to occur earlier or more powerfully than intended. When the knock sensor detects excessive knock, the ECU will alert you. When this happens, the engine will enter limp mode, and one or more of the DTCs listed below will be logged.

How do I know if my injectors are leaking?

Examine each fuel injector head where it attaches to the fuel rail closely. On the rail, injector body, or cylinder head, look for any evident dribbling leaks or fuel spray patterns. Check for odors of gas. A leak at the injector head indicates a problem with the injector body’s O-ring seals.

Can a leaking injector cause low compression?

Injector came out with intake, just like the prior time. The teflon seal ring had deteriorated/gone, as soon as the inspection was completed. It’s no surprise that air can now leak through the injector (worst leak down value), resulting in decreased compression.