Almaty mechanic David Mosinyan has described recurring cases of fuel injector fouling and explained why owners of cars with direct injection should pay closer attention to the condition of their fuel systems, the website infohub.kz reports.
According to the specialist, his Almaty service shop has recently seen a growing number of drivers arriving with fouled injectors. In some cases the deposits are so severe that a standard flush no longer helps.
"This epidemic of dirty fuel has shown just how fragile direct-injection injectors are and how demanding they are when it comes to fuel," the mechanic says.
As an example, he cited a BMW that came in for diagnostics after refueling. "The injectors were clogged so badly that no product will touch it. Right now we're selecting the right chemicals to remove all these deposits," Mosinyan noted.
The mechanic stressed that the vehicles coming to them with this problem are exclusively those with direct injection — GDI, FSI and TFSI.
In such systems, the injectors operate at high temperatures and pressures, and fuel is sprayed directly into the cylinders. Deposits on the nozzle can disrupt injector operation, and a standard flush does not always help.
The most telling case from the shop's practice was a car that covered about 2,000 km after cleaning before the problem returned. According to Mosinyan, after refueling again during a trip toward East Kazakhstan, the injectors became fouled once more. He did not disclose the name of the filling station.
The specialist believes that cars with classic port injection, such as older BMWs and Toyotas, run into the problem less often. For owners of direct-injection models, he advises not to ignore the first signs of trouble: worsening acceleration, rising fuel consumption and lean-mixture error codes.
At the same time, the mechanic recommends not rushing to buy new injectors or a high-pressure fuel pump (HPFP), but instead running diagnostics first. It should include checks of fuel trims, system pressure and injector performance. Even a spray pattern that looks normal does not guarantee that an injector is delivering the right amount of gasoline.
Drivers should also keep their fuel receipts and pay attention to symptoms appearing soon after refueling. This will help the shop establish a possible link to the fuel.
A fuel filter traps mechanical contaminants but does not remove compounds dissolved in gasoline, so a working filter does not rule out the formation of deposits. However, the cause cannot be determined from the appearance of an injector alone — confirming fuel-related problems will require testing the gasoline itself.
The mechanic claims his shop has already learned how to clean such injectors, but he considers it important to establish the cause of the repeated fouling.
Earlier, Kursiv Auto explained why cheap additives can make fuel-system problems worse.