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5 Signs Of a Bad Fuel Filter

Jul. 16, 2021

You can easily forget the fuel filter in your car, but if you do, you might regret it. Here is what you need to know to protect your fuel supply system and keep driving smoothly.

Poor engine performance

Under heavy loads, a clogged fuel filter may cause the engine to hesitate, surge or splash randomly. This situation is more obvious when accelerating, especially on steep slopes. Although there may not be any symptoms under normal driving conditions, when accelerating rapidly, a clogged fuel filter can cause the engine to lose extra fuel. The engine may also vibrate or stall at different speeds, depending on the degree of fuel restriction caused by dirty filters.

Hard start

Unless it is completely blocked, a bad fuel filter rarely prevents the engine from starting. For vehicles that have never replaced the fuel filter, a dirty filter can cause unstable fuel flow, causing the engine to start longer than usual before starting. Check your owner's manual for filter replacement intervals.


If an engine keeps stalling during driving, it may be warning you that the fuel filter is dirty. Similarly, depending on the severity of the blockage, your car can start immediately without any significant power loss. As congestion intensifies and fuel supply becomes more sporadic, the stall becomes excessive or worsens on acceleration. It is likely that the filter is completely clogged and it is time to replace it.

Random fire or rough idle

A clogged fuel filter will cause low fuel pressure, resulting in lean fuel and engine misfire. This may cause poor fuel mileage, rough idling, and may cause the inspection engine light to come. Once the light is on, it's time to go to the repair shop.



Fuel system component failures

A noisy, damaged, or failed fuel pump may be restricted by the fuel filter. The fuel filter is clogged, preventing the correct amount of fuel from reaching the engine. The fuel pump will try to compensate for the bad fuel filter, applying inappropriate pressure to the fuel pump motor, causing the fuel pump to fail prematurely.

The contaminants passing through the dirty fuel filter may damage, block, or cause the injector to leak, leading to various types of engine drivability problems. Unless it fails completely, replacing a dirty fuel filter and repairing or flushing the injector should get you back on the road with minimal expense.

The main fuel filter is replaceable. But before you take the DIY route, make sure the engine is cool, you have the proper tools, you release the pressure of the fuel system by pulling the fuel pump fuse (check the location of the owner's manual), and run the engine until it shuts down. Relieving Fuel pressure is critical because you don't want gas to be sprayed on the engine or the ground. Pay attention to safety and have a fire extinguisher nearby anyway.

Replace all o-rings, gaskets, and seals. Replace all mounting brackets and check to make sure that all fixing clips have been reinstalled correctly. Of course, check for leaks after installation.

There are several other reasons for engine loss of power and driving problems, but it is worth checking the condition of the fuel filter first. This is a cheap and easy method.

We are fuel filter manufacturers. Please feel free to contact us if you are interested in our products.


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