Signs Of A Cracked Fuel Injector In A Diesel Engine And How Your Mechanic May Identify The Faulty Injector

Posted on

If there is a diesel engine in your vehicle, the fuel injector helps ensure that sufficient fuel pressure is reached to start your car or truck. One common diesel fuel system problem is a cracked injector. Here are a few signs that a fuel injector is cracked and how the crack may be identified by your mechanic:

Signs of a Cracked Fuel Injector

Rising Oil levels

Many people are concerned when the dipstick in the oil compartment of their engine indicates that the oil level is subsiding. However, if there is a problem with the diesel fuel injectors of your vehicle, the oil level may actually rise.

Although the injector may be cracked, the engine of your vehicle may still run. Still, the crack may allow fuel to leak into the oil chamber of the engine. As the fuel contaminates the oil, it increases the amount of liquid in the oil compartment. As a result, dipstick readings may be higher than normal.

Difficulty Cranking

Cranking a diesel engine may take longer than normal when there is a problem with the fuel injectors. For most diesel engines,  the engine will not crank until an appropriate fuel pressure level is reached. If a fuel injector is failing, the crank time will increase because it will take longer for the fuel system to pump enough fuel for the proper threshold pressure to be reached.

How can your mechanic tell which injector is cracked?

Most people are unable to determine which fuel injector is damaged without the help of a mechanic. A mechanic will likely perform a visual test of the injectors initially. In order to do this, he or she must remove the valve cover and start the diesel engine.

After allowing the engine to idle, the fuel injector body can be observed for each of the engine's cylinders. An external crack will likely be easy to notice. There may also be a tiny bit of smoke being emitted by the damaged fuel injector.

The mechanic may also identify a cracked injector by removing the hard line between the fuel injector and the fuel rail. He or she can then cap the fuel rail and subsequently try to crank the engine. If the vehicle cranks more quickly, the offending fuel injector is identified. The steps are repeated for each cylinder until the cracked injector that is delaying start time is revealed. In some cases, an engine won't start at all if a crack is severe because the fuel system never reaches the threshold pressure needed to fire the engine.

To have your diesel engine reviewed for fuel injector problems, schedule an appointment with a mechanic in your area.