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Before you pay more at the pump for gas or go out and purchase additives and cleaning solutions it would be nice to determine if they are actually needed.
Testing the flow rate and the efficiency of the injectors can not only be performed but can verify whether cleaning is necessary.
A fuel injector is nothing but a on and off solenoid that allows fuel to flow on command. When the injector opens and closes it makes an audible clicking sound. In the old days injectors were quite loud and easy to hear.
On some newer vehicles you may have to use a mechanics stethoscope and place it on each individual injector to hear the clicking sound created by the opening and closing. If you do hear the clicking on each injector at least you know the electrical side is performing correctly. Injectors that are not being fired will not click.
The metering holes in the injector tips are drilled to precise specifications. You never want to use a wire brush or other cleaning utensils to try to unblock an injector tip. The basic idea for cleaning fuel injectors is that some type of cleaning chemical is run through the injector as an attempt to remove deposits or gummy build up.
One of the most effective methods is to replace the fuel supply with a strong cleaning solution. In this case the vehicle's fuel pump is disabled and an alternate supply of cleaning solution is supplied. Many automotive parts store sell pressurized containers of this type of injector cleaner with a hose that connects to the fuel rail.
During the cleaning operation the engine runs on this pressurized container of fuel/cleaner. You will have to carefully follow the instructions on the cleaner solution because often they recommend that you Pinch off the fuel return line to stop the cleaner from flowing back to the gas tank.
Although this method can be time-consuming and in some cases complicated it is much more precise than adding fuel injection cleaner to the gas tank to be run over a long period of time.
Note that after successful fuel injection cleaning that your engine may not seem to run right for several drive cycles. This can happen because your vehicle's computer has a learning memory. It may have already compensated for the dirty injectors as much as possible.
With successfully cleaned injectors fuel flow is returned to normal but the memory of the computer will have to catch up to this new condition. How long this will take will depend on the year make and model of the vehicle. In most instances this learning process will take only a few minutes or drive cycles.
source: onlineautorepair