Fuel System Deposits

Fuel system deposits can cause various driveability problems. Deposits usually occur during hot soaks after the key is in the off position. Poor fuel quality or driving patterns such as short trips followed by long cool down periods can cause injector deposits. This occurs when the fuel remaining in the injector tip evaporates and leaves deposits. Leaking injectors can increase injector deposits. Deposits on the fuel injectors affect the spray pattern, which in turn can cause reduced power, an unstable idle, hard starts, and poor fuel economy.

The intake valve deposits can also be related to the fuel quality. While most fuels contain deposit inhibitors, some do not and the effectiveness of deposit inhibitors varies by the manufacturer. If the intake valve deposits occur, the fuel may be suspected. These deposits can cause symptoms such as excessive exhaust emissions, power loss and a poor fuel economy.