Variable valve timing, or VVT, has been in existence since the 1960s. This is basically the name given to a very wide array of techniques that is used to generate greater power from the engine at higher speeds or when the engine is under a load pressure.
Different car manufacturers have different variable valve timing systems, yet almost all of them depend on a variable valve timing solenoid to control the flow of oil to the VVT system when engaged because VVT does not work on idle, and only comes into play during higher speeds/ when there is load needs. Thus when the solenoid is activated, oil is sent from the system to lubricate the VVT chain and gear. However, if the solenoid has failed or is clogged, the system will not work and will need replacement. Below are signs of a failed and or failing solenoid.
CHECK ENGINE LIGHT
One of the first symptoms that might indicate a bad or failing VVT solenoid is the Check Engine Light comes up on your dash. This shows that a code has been sent and stored on the car’s computer. Checking the code will give more information about the particular fault. You must however, know that there are other different generic VVT-related codes, as well as other specific codes used by different specific car manufacturers. If your Check Engine Light appears at any time, prompt investigation should ensue.
Because the VVT system uses oil, dirty oil can bring problems, especially for the VVT solenoid. If your engine oil has become dirty, it should be changed before any other thing about diagnoses is done. Debris in the oil can buildup in the system and cause the VVT inoperable or erratic.
LOW ENGINE OIL
Since oil is important to an operable VVT system. If the engine oil gets low, there’s a possibility that the solenoid is not able to send oil to the VVT system during use and this will cause damage to the VVT chain/gear. This is not really related to a damaged solenoid.
Even when the variable valve timing system does not at idle, a failed solenoid can cause a rough idle.
LOSS OF FUEL ECONOMY
Another sign of a failing variable valve timing solenoid is loss of fuel economy. This happens because the system can no longer control the amount of intake and exhaust valve overlap during engine operation.