This method is called : Closed CircuitCirculation . It means that the fuel is runing from the bottle and returning back to the pump without passing through the fuel tank .brYou can use any fuel cleaner brand you want .brIts fast and easy to clean injectors and injection pumps (both diesel and petrol injection systems ).brRecommended to do it once per 2 mounths to keep your injection system clean and effecient .brAll you have to do is disconnect the in and out fuel pump tubes and hook them into the bottle,then start your engine and keep it running for 10 mins .brYou will notice an engine sound inprovement (run smoother and healthier than before)brAfter finishing this step hook up everything in original mount and start the engine for 2 or 3 mins to let the fuel cerculate into the pump again and your done.brTake your car for a ride if you want .brN.B : if you have troubles to restart the engine after this method, dont worry. All you have to do is purge the fuel suction cup to let it go into the pump ,then start your engine .brIf you find this helpfull please give a thumbs up and comment below.brSubscribe for more !brThanks for watching.