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We at Injector Rx are not aware of a specific  “tool” available for the cleaning of fuel injectors.

Fuel injector cleaning is done with a combination of tools and specialized equipment. Fuel injectors should be tested for flow and atomization once cleaned

 

A remanufactured fuel injector is a used fuel injector that has been ultrasonically cleaned, flow tested to make sure it complies to manufacturer specification and then fitted with new O-rings, filters and pintle caps.

Fuel Injector Balancing mean the fuel injector both in spray pattern and in quantity of fuel delivered are even.

Fuel injector manufacturers in general send their fuel injectors as balanced sets to the end users such as auto, motorcycle, marine engine etc. manufacturers.

Due to dirt and contamination buildup over time fuel injector spray pattern and quantity delivery will change and become uneven. This in turn can cause many drivability or engine performance issues. To correct this all that needs to happen is for the fuel injector set to be ultrasonically cleaned.

Occasionally a fuel injector set just does not perform evenly and it requires to be “balanced”, but here is the catch in the phraseology being used on the internet. “We flow test and balance fuel injectors”

The flow testing part is correct but the balancing part is a myth. To our knowledge there does not exist a company that can precision drill or re-drill the fuel injector outlet holes or regrind the pintle shape to such exacting specs that will allow for precision balancing in both spray pattern and flow. Yes there are companies that can re drill the outlet holes of the fuel injector nozzle by means of laser but they cannot guarantee that the injector set you send them will be balanced.

So how do they balance fuel injectors both in manufacturing and in the aftermarket?

In manufacturing the new injectors are flow tested and then sorted in groups consistent in spray pattern and volume. Balanced set in the aftermarket is a whole different ballgame. Injectors are sourced from junk yards, cleaned and then flow tested. Fuel injector styles with the same volume are put together as flow matched sets. The same happens when fuel injectors are modified to make them deliver more fuel. Injectors are modified in bulk. They are then matched in volume but not in spray pattern.

It is highly unlikely that the same set of unbalanced fuel injectors sent to one of the companies claiming that they do fuel injector balancing service will return that original set of fuel injectors as a balanced set.

There is nothing wrong with doing this … just a misunderstanding of the terminology.

From time to time injectors need to be stored. Since corrosion is probably the injectors number one enemy the question then becomes how to store fuel injectors properly. Insure that the injectors are cleaned properly and lubricated, inside and out, with a good quality lubricant. The injectors should then be placed in a sealed plastic bag or container and stored in a cool dry place.

The cause of fuel injectors going bad when not in use is in part because large parts of America contain enough moisture to cause corrosion/rust damage. The internals of injectors are made of various steel alloys that will corrode and or rust when in the presence of moisture.  Gum, varnish and other normal deposits can be removed by cleaning but once an injector dries out and the deposits hardened inside causing a pintle to get stuck to its seat, that injector will become inoperable and in most cases not possible to clean.

All gasoline based fuel injectors available in the United States or in the rest of the world for that matter are sealed units. The term: remanufactured fuel injectors, rebuild fuel injectors, reconditioned fuel injectors and or refurbished fuel injectors are misleading and a myth when it comes to fuel injector cleaning service.

It will be cost prohibitive to take these dirty or clogged fuel injectors apart, replace and or clean internal components, re assemble and then reseal the injector. To our knowledge there is not a company that performs this exact service.

Most companies offering a fuel injector cleaning service are basically doing the same thing. When the dirty fuel injector or clogged fuel injectors arrive for service those components that can be removed from the fuel injector such as O-rings, pintle caps and filter baskets are removed. The injector then is placed in an ultrasonic cleaning bath to clean the external part of the fuel injector. Once this is done the fuel injector is then connected to an electronically controlled machine that has the ability to pulls the fuel injector at various speeds. The injector is now placed in a second ultrasonic cleaning bath in such a way that the nozzle of the injector is amerced in a cleaning solution. The opening and closing of the pintle valve combined with the cleaning solution, agitated by the ultrasonic waves now cleans the internal components of the fuel injectors. The pulsation of the fuel injector combined with the ultrasonic waves force the cleaning solution to move up in the injector thus causing a flush effect on the injector and therefore expelling dirt and debris from the fuel injector internals.

Once it is established by means of flow testing and visual inspection that the spray patterns are correct and that the fuel injectors are clean, new filter baskets, pintle caps and O-rings are installed and the fuel injector is now ready for service again.

If after several cleaning attempts the flow pattern cannot be corrected and or quantity delivered by the injector is still not within spec the injector can be deemed as unserviceable and the fuel injector should be replaced.

When choosing a business to do your fuel injector cleaning make sure of the following:

• The business can be contacted during normal offices hours.
• There is always somebody to answer the phone.
• The business has a legitimate business address.

Hydrocarbons and additives which forms part of today’s fuels evaporate at different temperatures. Small amounts of gasoline are left behind on the tip of the injectors each time the engine is shut down. Volatile compounds in the fuel evaporate and while others stay behind on the injector tip and eventually form solids. These solids accumulates and eventually start effecting the spray pattern and fuel distribution which in turn can have detrimental affects on the overall well being of the engine.

Higher operating temperatures of turbo and supercharged engines are very tough on injectors, especially due to higher intake temps and sometimes reversion. The same is also true for high performance engines with large duration cams.

Many high performance air filters does not clean the air sufficiently and contributes to the fouling of injectors. Dirty fuel filters and failure to regularly replace them is also a contributing factor

Moisture in the fuel tank that could eventually lead to rust being deposited below the injector filter and can cause catastrophic failure of not only the injector but in some instances the engine

Engines with worn rings and valve guides greatly contribute to the clogging of fuel injectors.

Fuel flowing through the injector helps to keep the injector cool and in most cases prevent it from overheating.

Impedance measures how easily a circuit conducts current when a voltage runs through it. Measured in ohms, impedance is a way of telling you how much of the voltage introduced at one end will really make it to the other end. Impedance depends on other qualities of electricity, such as resistance, reactance, inductance, and capacitance.

Most injectors fall into two categories: High or Low Impedance

High Impedance.

These have a typical coil resistance of 12 – 16 ohms and are the most commonly used. Drive circuitry for this type of injector is simple and sometimes referred to as a saturated driver circuit. The injectors them selfs are also refered to a saturated injectors.

Low Impedance.

Low Impedance Injectors has normally a coil resistance of 4 ohms or less and is typically found in larger sized or high performance injectors. Driver circuitry for these types is called a Peak – Hold type and is more complex and costs more than the saturated type.
In a Peak – Hold system, the driver circuit allows a high current for a short time to help turn the injector on quickly. The current is then reduced to a lesser value to keep the injector open. Peak current may be 4 amps to open the injector. Once open, the current might be reduced to as little as 0.75 amps.
With the lower coil resistance, the internal spring pressure that holds the pintle closed can be increased to shut the injector quicker. This allows both faster opening and closing times and makes tuning large injectors easier.
Peak – Hold systems reduce the power requirements to the injector coil thus keeping the coils from overheating.

Manufacturers rate fuel injectors by the maximum amount of fuel that they can flow in a given amount of time at a given pressure. This measurement is known as Static Fuel Injector Flow Rate and is normally taken at 100% duty cycle and a fuel pressure of 43.5 PSI.

Example: At 100% duty cycle a 55 pound (lb) injector at 43.5 PSI of fuel pressure will flow 55 pounds per hour.

Injector Flow Rates are expressed in pounds per hour (lb/hr) or cubic centimeter per minute (cc/min). Given the same pressure 1 lb/hr = 10.5 cc/min.

To convert lb/ hr to cc/min, multiply by 10.5
Sometimes injector flow rates are expressed in milliliter per minute (ml/min)
1 ml = 1 cc

Example: a 220 cc injector = 220 ml injector

Fuel injector static flow rate is the maximum fuel a fuel injector can flow at a given pressure.

If an injector stays on all the time, 100% duty cycle, it is said to be static. Injectors should never go static because control of fuel delivery is lost and this can cause catastrophic engine failure. Static injectors, or 100% IDC is normally an indication that the injector is too small for the engine. Injector duty cycle should usually not exceed 80%. Once 80% IDC is reached a bigger injector should be installed.

In some instances low fuel pressure or a failing fuel pump can cause injectors to become static. On the other hand, there are some injectors that will go static if the fuel pressure is too high.

To control the amount of fuel that enters the engine the injectors are turned on and off or pulsed very quickly. The amount of time an injector is turned on to delivering fuel is known as injector duty cycle. This is measured as a percent, so 50% duty cycle indicates that the injector is held open and held closed for an equal amount of time. When the engine needs more fuel, the time that the injector stays on (its duty cycle) increases so that more fuel can flow into the engine. If an injector stays on all the time, it is said to be static (wide open, or 100% duty cycle).

Fuel from the fuel rail, under pressure, is sprayed in a very fine miss from the tip of the injector. To achieve this, a current must flow through the fuel injector electrical field coils. Contrary to popular belief, this is NOT done by sending power to the injector. Fuel injectors are normally fed power whenever the ignition key is on, but the circuit is not completed and therefore the injector is still close. The computer controls the ground side of the circuit. When the computer provides the injector with a ground, the circuit is completed and current is allowed to flow through the injector. This energizes an electromagnetic coil inside the injector, which pulls a sealing mechanism such as a pintle, ball, or disc away from its seat. This makes it possible for fuel to flow through the injector and into the engine. When the computer removes the electrical ground to the injector, the electromagnetic coil becomes demagnetized and a spring forces the pintle, ball, or disc shut to cut off fuel flow. Even at an engine speed of just 1000 RPM, this is done hundreds of times per minute.

Most fuel injectors consist of a body that houses an electromagnetic coil and a sealing mechanism such as a pintle, ball or disc. These sealing mechanisms are usually kept close by means of a spring.

Injectors are fully open or fully close. The amount of fuel injected is determined by how long the injector is open or by how long the pintle, disc or ball is removed from its seat.

Failed emission:

• Performance lost
• Engine does not reach full RPM
• Increased fuel consumption
• Poor idle
• Surging an bucking under light throttle
• Smoke from the tail pipe
• Detonation which can lead to catastrophic engine failure
• Pollution

Leaking injectors will cause:

• Increased Fuel Consumption
• Poor Idle
• Fuel odors inside and around the car
• Hard Starting
• Poor Emissions
• Oil thinning which can lead to catastrophic engine failure
• Hydra lock

External injector leaks is a fire hazard and can not be fixed. Injectors with external leaks must be replaced.

Simply put; a fuel injector is an electronically controlled valve that is either fully open or fully close. The period the valve is fully open is measured in millionths of a second. Its  purpose is to supply the engine with enough fuel and it is controlled via the engine management system.

Fuel Injectors have the finest tolerances of any mechanical part on the engine. They are very resilient and does not go bad often. In most cases the fuel injectors can be restored to original factory specification with proper fuel injector cleaning service techniques.