Mazda6 Fuel Injector Problems

Your fuel injectors are the central component of the entire fuel injection system. When you're having fuel injector issues in your Mazda6, it can be a nightmare to diagnose. Hopefully, you'll find the solution in this breakdown of fuel injection issues and solutions. (Be sure to check out our parts guide, too.)

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The Basics Of Fuel Injectors

Mazda6 injector issues

Fuel injectors are valves that have electronic controls that are given signals from the control unit of your Mazda6’s engine. The gas pump sends the pressurized fuel into the injectors, which open and close based on signals from the engine computer. Fuel is then jetted into the airstream just outside the cylinder (or, on some models, fuel is injected directly into the cylinder). The fuel mixes with oxygen and combusts, and we have locomotion. When the engine asks for more fuel, the valves stay open longer. This time is called the "pulse width."

Symptoms Of Injector Issues

Engine power is inconsistent. If you have an engine that is revving high and low, you have a dirty fuel injector. You will see a fluctuation in the tachometer.

Engine misfires. If the fuel supply is inadequate, then the engine will misfire. Any reduction of 8 to 10 percent can cause a misfire. This means that you can have a dirty fuel injector, a fuel injector that is not opening or is clogged.

Engine idle is uneven. There should always be a smooth idle, but if the gas is unevenly supplied, you are going to see a rough idle. This is caused by a dirty fuel injector.

Fuel smell. A faulty injector creates a strong and obvious fuel smell. This is due to a fuel injector either leaking or not closing.

Poor fuel economy. When the fuel injectors are not sending the right mixture of fuel, your engine asks for more, which lowers your fuel mileage. This is due to a fuel injector leak or one that is not closing.

By paying attention to your vehicle symptoms, you can resolve problems before you run into more trouble.

Common Injector Problems

Dirty or clogged fuel Injectors – Injectors can become caked with grime over time, causing them to become clogged. This keeps them from spraying the proper amount of fuel. A simple fuel system cleaner will usually fix this -- if nothing else remove them and soak them in fuel injector cleaner.

Fuel injectors not opening – If the valve in your injector is not opening, fuel cannot be delivered. There may be a fault in the windings or a rusted injector. Windings can overheat, break, or short.

Fuel injectors not closing – A bad spring can keep the injector from closing, as will rust or additive build up -- it then can leak fuel.

Leaking fuel injector – Should you have another failure in the system, you may have a gas leak due to overheating and failure of the injector. Additionally, you may have a faulty injector.

Diagnostic Testing

You can run some tests yourself, but you may need to use some uncommon tools.

  • Manifold temperature testing. You need a laser thermometer to perform a temperature test on the exhaust manifold. The normal temperature is plus or minus 30 degrees of 450ºF. A temperature around 200 to 250ºF means the valve on the injector is not opening, and a temperature around 600ºF means the valve is not closing.
  • Listening to the injectors. You can use an engine stethoscope to listen to your fuel injectors. They should click sharply when they are operating normally. If you do not hear any sound, you have a problem.
  • Injector inspection. You can take the injectors out and manually inspect them. Detach the fuel rail, and then detach the injector from the rail. There may be a bit of fuel that comes out of the rail when you take the injector off, so make sure you protect your hands. Look at each injector for damage or cracks.

These tips should help your find and fix your fuel injector problems. If you find that you cannot diagnose your fuel injection problem or after fixing it you are still having trouble, you may need to consult with your local Mazda dealership. If you end up having to replace your injectors, you can find high quality OEM replacements here.