If you've got a car with a replaceable fuel filter, you need to replace it every 2-4 years. Many people wait until they experience the symptoms of a bad fuel filter to replace it. If you notice some symptoms, you want to confirm that your fuel filter is bad ASAP. The longer you drive with a bad fuel filter, the more your engine suffers.
Luckily, diagnosing a bad fuel filter is pretty easy to do. In this tutorial, we'll show you how to do this.
There's No Reason Not To Replace Your Fuel Filter
Before we start, we want to talk a bit about replacing your fuel filter. It's a pretty easy and straightforward process. There are many model-specific fuel filter replacement tutorials online. You can also check your owner's manual for instructions.
It's equally as easy to find an OEM replacement fuel filter. All you have to do is to look up your Mazda model in our catalog of OEM fuel filters. You'll get the right part number in no time. This fuel filter for certain 2012-2019 models is one of our best sellers.
The Most Common Signs Of A Bad Fuel Filter
If you experience any of the following signs, chances are your fuel filter is bad:
- Difficulty starting your car
- Vehicle jerking while driving uphill
- Poor fuel consumption
- Loss of power when your engine's load increases
- Engine stalling while idling
- Sputtering or coughing engine
Two Ways To Confirm That Your Fuel Filter Is Bad
If you want to confirm that your fuel filter is bad, you have two options:
- Perform a fuel pressure test
- Visually inspect the fuel filter
Let's go over each method in more detail.
1. Performing A Fuel Pressure Test
This method is best when your fuel filter is hard to access. For example, if your fuel filter is inside the fuel pump, it's much easier to perform a fuel pressure test. You would need a fuel pressure gauge. Here's an overview of doing a fuel pressure test:
- Find the fuel pump test point. It's commonly in the fuel line or near the fuel injectors. If you're not sure where it is, check the service manual. There should be either a separation joint or a test port.
- Turn the engine on and then let it run for about 5 minutes.
- Check the psi level on the gauge. That's the idling pressure.
- Check the repair guide for the recommended pressure level. If your psi reading is at least a few pounds lower, the filter may be clogged.
If the fuel pressure is low, then the filter is likely clogged. It could also mean that the fuel pump is failing. Since a fuel filter is inexpensive, you can just replace it. If you still experience the symptoms listed above, you may want to check the fuel pump. If you have dropped the fuel tank to get at the filter and pump, you should probably replace both at the same time.
2. Visually Inspecting The Fuel Filter
If it's easy to access the fuel filter, it's worth taking a few minutes to inspect the fuel filter. Some fuel filters come with a window that allows you to look inside and see the paper filter media. Does it look dark, dirty, or clogged up? If so, you need to replace the fuel filter ASAP.
If you can't see inside the filter, check the condition of the outside. If it looks old and rusty, then it's best to err on the side of caution and replace it.
If in doubt, replace the fuel filter. Fuel filters are pretty inexpensive, so it can't hurt to replace it anyway.