A fuel injector.

What is a fuel injector?

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

Certain components need to be in good working order in order for your vehicle’s engine to run properly.

Its performance can be impacted when there is a problem with the fuel injectors. These parts are responsible for sending fuel to the cylinder, allowing the engine to operate.

A 2008 Jeep Wrangler that was brought to HomeTowne Auto Repair and Tire needed new fuel injectors. The vehicle’s check engine light had turned on, and it had a fuel injector code.

The intake manifold on a Sahara Jeep Wrangler.
Intake manifold on a Sahara Jeep Wrangler

Replacing fuel injectors

To reach the fuel injectors, we needed to remove the intake manifold. On this Jeep Wrangler, the exhaust gas recirculation (EGR) tube runs from the valve on top of the intake.

While working on the vehicle, we realized that a fuel injector was out of specification. We needed to install new injectors before rechecking it.

The steps to replace fuel injectors vary among vehicles. Some fuel injectors are in the intake manifold. Others are mounted directly into the cylinder head like a spark plug. That’s called direct injection.The general injector replacement process includes releasing fuel pressure, disconnecting the fuel rail, and pulling the fuel injectors out of the fuel rail.

Intake manifold.
Intake manifold

The number of injectors depends on the cylinders. Most vehicles have one per cylinder but some have two for each cylinder.

Fuel injectors normally last the life of the vehicle. However, there are a few common issues found with some automobiles. For example, when certain Chevrolets reach 70,000 or 80,000 miles they will have a misfire at a cold start. This problem tends to resolve itself as the engine warms up. We’ve worked on a bunch of those vehicles. 

Signs of fuel injector problems

The check engine light turning on isn’t the only sign that the fuel injectors aren’t working correctly. You may also notice the vehicle is riding rough and lacking power.

Other indicators of a fuel injector problem include the car having trouble starting or using more fuel than normal. 

Another symptom that can appear if something is wrong with the injectors are engine misfires, which is when the fuel isn’t ignited right.

As high tech as some of these vehicles are becoming – such as certain Mercedes engines – it could take a while to diagnose and track down what your misfire problem may be due to the injectors. 

A direct replacement may not be a fix. The manufacturer may have to read the values of the injectors overtime, and they can recommend what cylinder the injector should be put in to balance out the engine. 

However, it’s always good to check the basics first, such as spark plugs, ignition coils and the operation of the fuel injectors.

Fuel injector maintenance

The best way to make sure a vehicle’s fuel injectors last is to take care of them over a period of time. Having fuel induction services conducted regularly is one way you can maintain them. 

Recommended every 30,000 miles, the fuel induction service cleans out the air induction and fuel injection systems. Contaminants are removed from fuel injectors and other parts by a fuel system cleaner.

It’s a good idea to replace any bad fuel injectors in your vehicle sooner rather than later. If you have a symptom that’s linked to a fuel injector problem and the part isn’t replaced, the symptom will continue to grow worse.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Lake Ridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.