The Gas Injectors represent one of the focal points of a Gas System.
Their malfunction could be the reason for major problems and even a risks for driving.

Therefore their Periodic Maintenance is essential, and linked to many factors:

- Gas Filters: if the filtering is accurate, the filters will clogs easily, but the Gas Injectors will be less dirty. The Gas Tanks, although new, often contain dirt that contribute to dirty the filters and to reduce their functionality: as we all know, the filters work well when they are clean, but they do damage when they start to get dirty, therefore: watch the Maintenance of Filters

- Gas Quality: not all Gas are equal, in fact to the producers is given the right to vary, unfortunately with a certain amount of discretion, the percentages of its components, sometimes also as a function of the ambient temperature, that if too low would impede its normal use. Fortunately the ECUs equipped with OBD control, performing automatic corrections, at least do not suffer from such harmful variations. Sometimes even the Gas Tanks, at Service Stations, are not thoroughly cleaned and mix with the Gas dirt of various nature

- number of Hours of Operation, stated by the Manufacturer: Some injectors are sold for 30,000 kilometers, others to 100,000 kilometers, etc ... depending on the characteristics of the materials they are made and the technical measures taken to reduce the wear.

Some softwares allow you to set the number of operating hours before reporting the need of maintenance.
To obtain an average value of the hours to the next maintenance, depending on the routes and the speed, for example 50 km/h as average, for 100,000 km the calculation is:

100.000 Km / 50 Km/h = 2000 hours

- type of Injection: Semi-Sequential Injection (2 openings per Turn) increases the wear and will reduce further the work hours, a Fullgroup Injection much more.

The ability to extend the life of a Gas Injector also depends on the Control Unit driving it, which can sometimes enhance the duration with certain precautions, as our POWERFUeL

The problems that can affect the correct functioning of the Gas Injectors are therefore substantially of two kinds:

1. 1 - DIRT, which is solved with a good cleaning
   

2. 
   

3. 2 - and WEAR, more complex to manage, that is resolved by the replacement of worn parts or of the entire Injector

After having understood that one of the Gas Injectors is leaking (see our previous tutorial HERE ) let's take a look at how to disassemble an injector and to perform its cleaning properly.

CLEANING

First, to Remove the Coil, pry the e-clip washer with a screwdriver

Then Remove the Coil

Unscrew the Shutter Housing

Remove the Shutter

Since each Shutter Housing is calibrated, generally by robotic machines, to work with a specific Shutter, it is good not to mix the various pieces nor swap their position, otherwise the Injectors will be not calibrated anymore and you will need to recalibrate them necessarily! operation not so easy. For this reason we strongly recommend to clean up a Shutter at a time, and reassemble it each time, before putting hands on the next.

Clean the Shutter-Housing, the Shutter and the Spring by using only AIR and White Petrol, like the one used for lighters, being careful not to damage the rubber parts

or use only any Specific Liquids or Spray, suggested by the Manufacturer, AVOIDING ALCOHOL or SOLVENTS by which you risk irreparably damaging the rubber parts!

An alternative is to use an oil, fluid enough to brush the components to remove any encrustations.

After thoroughly cleaning the Shutter, carefully watch the rubber parts and if they are damaged, or if you see that, after reassembling, the Injectors still leak, it means that it is necessary to replace the Shutters with original parts.

Before assembling, if necessary, also replace the Shutter-housing o-ring seal, lubricating it slightly.

CALIBRATION

If it was necessary to replace the Shutters, or if you doubt you have shuffled the various Shutters, reversing their original position, you will probably have to re-calibrate the Injectors. To be sure that this operation is necessary, first try to keep the engine running on Gas mode, at idle and, if it seems irregular and unstable, you will have to re-calibrate the Injectors.

The Calibration Operation is to ensure that the excursions of all the Injectors' Shutters, on the same engine, are equal to each other, otherwise an Injector would supply a quantity of Gas different from another. Unfortunately, the quantity of Gas dispensed substantially changes even if the excursion is different of just a few hundredths of a millimeter! For this reason it is a delicate operation that might jeopardize the success of the cleaning just made.

To Perform a Calibration you have basically three different ways.

1 - BY USING A DIAL GAUGE:

Specific Dial Gauges are available on the market just to calibrate Gas Injectors, equipped with an adapter that allows a quick application on the rail of the Injectors. Then you will not have to waste your time to lock both the Injectors and the Dial Gauge in such a position that allows both a precise measurement, and in the same time, a maneuver of adjustment of the fixed core, by means of an Allen Wrench.

The Excursion for which every single Shutter must be calibrated depends on the Injector Model used. These data are declared by its Manufacturer. Generally the range is between 0.3 and 0.6mm, but the tolerance in the adjustment is just ± 0.03mm, so great caution must be applied.

If you don't know this information, we suggest taking a new identical block of Injectors, and measure its excursion. If also this is not possible, take as a reference the average of the readings you can get on the 4 injectors of the same old rail, because the most important thing is that the 4 adjustments are the same.  However, keep in mind that a shorter excursion allows a better response, and the injector will be able to open with smaller injection pulses, but at the expense of the flow rate that will be lower; on the contrary, a larger excursion allows a larger flow, but it makes it difficult to open the injector with small pulses, unless you use our POWERFUeL that opens any injector with less than 1 ms time.

To perform the measurement, put the Dial Gauge probe in touch with the rubber of the Shutter and zero the instrument by its reset button. Now, to measure the excursion, it's necessary to supply power  to Injector Coil, that will attract the Shutter, allowing its displacement and the relative measurement.
The Coils of the Gas Injectors are a few ohms, generally from 1 to 3 ohms, then the measurement operation must be rapid enough to prevent the coil will melt! or that the winding enamel will be damaged, causing a low insulation.

Instead of using the 12 volts, it would be preferable to use a 6 volts power supply, of a suitable amperage (4 or 6 Amps), in the absence of which we suggest you to make a cable of this type, with 2 (or more) injectors in series,

to stress the Coils as little as possible, but using the 12volts, easier to withdraw from the Battery of the same car; so they will trigger two at a time, but with less stress.
Rotate the Allen Wrench until between the rest and opening position there will be exactly the excursion necessary, for example 0.60mm for the Rail Apache IG1 Injectors.

2 - BY A HOMEMADE METER:

A DIY (do it yourself) method, but quite effective if it's well done, is to build a Calibration Apparatus in the manner described herein. We didn't Patent it :) so you are free to use it.

First, you need to build a tool, made up of a jar with airtight lid, like what you use for jams, in which to drill 2 holes for the installation of 2 fittings for rubber hoses, for example with quick-connection for teflon pipes. Partially fill it with water or colored liquid.

Connect the Injectors to a Gas ECU, you can even connect only the RED wire (Battery 12v), RED-WHITE wire (Key Switch, also on Battery 12v) and BLACK wire (Battery Ground).
Connect the Injectors to an Air Compressor and adjust the Air Pressure to approximately 1/2 bar, otherwise the quantity of liquid that will be moved will be exaggerated and, despite the fact that the outlet pipe is long enough, you might take a shower. If your compressor does not allow this adjustment, interpose an old Reducer between the compressor and the Injectors.

Connect only one injector at a time to the inlet tube.
Open the Software and in the Test window, when everything is ready, click on TEST GAS Injectors to start the Test. In this way the Gas Injectors will open alternately for 4 milliseconds, with intervals of about 2 seconds, giving you the time to stop the Test when completed.

Decide with a test if 1, 2, 3 or more openings of the same Gas Injector are required to raise enough the Column of the Liquid in the pipe.
Mark on the pipe, with a small piece of insulating tape or by a small oring, the Arrival Point of the Column of Liquid, which will be also the arrival point for all the other injectors, following the same number of openings.

Obviously if the column stopped too high or too low, compared to the first injector, rotate a little bit the Allen Wrench and repeat the Test after removing the Injector pipe in question and having waited that the level of the liquid in the measuring pipe has fully dropped into the receptacle.

While the Test is paused, if the liquid inside the pipe does not maintain its stable level but it goes up or down, it means that there is a leakage on the Injector's Shutter.

For those who have the good habit to perform these calibrations frequently, it is advisable to equip a stable workbench, with Control Unit, Power Supply, watertight container, pipes, etc. ready for use, which allows greater speed of execution, without having to rebuild it every time, maybe adding a fast air button or drain cock to reset the level in the pipe, without bothering to detach the injector to perform more than one test, creating in this way an accurate Gas Injectors Test Bench, almost at No Cost.

3 - BY EAR:

A deprecable method, but nevertheless practiced by those who have good hearing for the engine, is to keep the engine running at idle and, with the help of the changing over of one or more Petrol or Gas Injectors, it is possible to "tune" the injectors in the same way you do with a musical instrument

If you had to Calibrate the Injectors, we recommend repeating the system self-calibration.

Finally, it must be stressed that in many Countries, where labor cost exceeds the cost of the material, if maintenance goes beyond a simple cleaning, the complete replacement of the injectors with new ones is without doubt the most affordable way, for the benefit not only of assured efficiency, but also to reduce the dwell times in the workshop.