The Fuel Injector Balancing Myth!

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.

How to Store Fuel Injectors?

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.

Can a Fuel Injector be Rebuild, Reconditioned or Refurbished?

Almost all gasoline based fuel injectors are sealed units. The term: remanufactured, rebuild, reconditioned and or refurbished fuel injectors are misleading and a myth when it comes to fuel injector service.

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

Fuel injection cleaning 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. The fuel injector is then connected to equipment that has the ability to pulls them at various speeds. The injector is now placed in a second ultrasonic cleaning bath with the nozzle of the injector immersed in a cleaning solution. The opening and closing of the pintle valve combined with the cleaning solution and ultrasonic waves agitation 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. Thus flush affect expel 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 un-serviceable and the fuel injector should be replaced.

Beware of fuel injection cleaners. When used at the wrong time they can cause severe engine damaged

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.

What is Fuel Injector Impedance?

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.

High Impedance fuel injectors  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 self are also referred 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.

What is fuel injector static flow rate?

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.

What is Injector Duty Cycle?

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).

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