Dirty fuel filters are a common problem on all cars, even those as sophisticated as BMWs. Yet many people still aren't sure how to recognize the signs that a fuel filter is nearing the end of its lifespan. If you would like to improve your ability to diagnose common automotive problems, read on. This article will teach you to recognize two common symptoms that a fuel filter needs to be replaced.

Your car is having a harder and harder time driving up steep grades.

As its name would imply, a fuel filter is responsible for removing any dirt or impurities from your gas before it passes into the engine. Otherwise those impurities would quickly wreak havoc on the delicate mechanical systems inside an engine. Over time, a fuel filter will have absorbed a great enough amount of these unwanted substances that fuel can no longer pass through it correctly.

In the early stages, this type of build up may not cause problems when traveling over level ground. But when it comes time to drive up a hill, suddenly your car may seem to be struggling. That's because the restricted fuel filter prevents your engine from receiving the increased amount of fuel it needs.

At first this problem may seem relatively mild. But, as time goes on, your car will have to struggle harder and harder to get up even relatively low-grade inclines. If the problem is allowed to persist long enough, it may even cause permanent damage to the fuel pump and other components of the fuel system.

Your car produces black stinky exhaust when accelerating.

Black exhaust smoke in general is a sign that the fuel mixture inside of your engine is too rich. In other words, there is too great an amount of fuel and too little air. In other words, that black smoke represents the excess fuel being burned off. While this can be caused by a variety of different problems--everything from a leaking fuel injector to a poorly adjusted choke--it is most commonly the result of a dirty fuel filter.

At first this may not make sense. It would seem that if fuel is having too difficult a time passing through the filter, the result would be a fuel mix that is too poor, not too rich. Yet the key factor here is the pressure of the fuel entering the injectors. Because of the increased resistance of the dirty filter, the fuel pressure is much greater. Having a fresh fuel filter installed should greatly reduce the severity of the problem.  

Talk to a professional from a company like Jim Stephen's Foreign Car Repair for more information on fuel filters.