Diesel Engine Running Rough? Get the Air Out of Your Fuel

Diesel engines require clean fuel that’s free of air and vapor. But agitation due to the vehicle’s motion introduces air bubbles to the fuel, as does the fuel return system. A fuel air separation system can help your engine deliver more power and extend its life by separating entrained air and vapor from your fuel before it gets to the injectors.

Difficulty Cranking

Air in your fuel will reduce your fuel pressure and make it more difficult to crank. If you see excessive smoke on startup, this is a sign that you’ve got air in your fuel. This problem may be most extreme in cold weather.

Problems in Deceleration and Idle

If you experience a loss of power or stalling when decelerating or idling, this can be caused by air in the fuel. Your injectors are struggling to deliver enough fuel to the engine.

Surging and Low RPM

If your engine will not maintain a steady RPM or will not reach the rated RPM, this is likely due to low fuel pressure. This can be due to a number of factors in the fuel system, but fuel with excessive air entrained in it is often the culprit, as it affects your fuel injector timing. A fuel air separation system prevents this by reducing the amount of air in the fuel.

Engine Damage Due to Air in Your Fuel

Cummins® and Caterpillar® manuals both caution that entrained air can damage fuel injectors if left unchecked. Lubrication and cooling of the injectors depend on a supply of fuel that’s relatively free of air. Cavitation in the injectors disrupts fuel supply and injector timing.

You can increase your horsepower, ease of startup, and engine life by installing a system to remove excess air from your fuel. An aftermarket system that separates the air from the fuel can get the job done.