In this article, I'm gonna' show you one of the fastest and easiest ways I have used to diagnose bad fuel injectors on Nissan vehicles. You don't need any expensive diagnostic equipment to do it... all you need is a multimeter.
In this article I'm gonna' show you how to do a simple resistance test, with a multimeter, to diagnose a fried fuel injector.
Contents of this tutorial:
- Symptoms Of A Bad Fuel Injector
- What Tools Do I Need To Test The Fuel Injectors.
- The Fuel Injector Test.
- Interpreting The Results Of The Fuel Injector Test.
- Which Fuel Injector Do I Test First? Or Do I Test All Of Them?
- My Nissan Doesn't Start.
- Fuel Injector Tutorial Summary.
- More Nissan 2.4L Test Articles.
Symptoms Of A Bad Fuel Injector
In my experience, the three major causes of a fuel injector fault/problem are:
- Fuel injector doesn't spray any fuel.
- Fuel injector sprays fuel, but not enough (clogged fuel injector).
- Fuel injector stuck On all of the time (as soon as the key is turned On).
This article focuses on the most common, which is when the fuel injector doesn't spray any fuel at all. When this happens, it's because the fuel injector has fried internally.
What really stinks about having a fuel injector go bad, or get clogged, or stay stuck On all of the time, is that the PCM (Powertrain Control Module = Fuel Injection Computer) doesn't set a specific fuel injector malfunction trouble code.
So, one of the things that you and I have to do, when we suspect a bad fuel injector, is to do a fuel injector resistance test (and in this tutorial, I'll show you how).
What Tools Do I Need To Test The Fuel Injectors?
To test the fuel injectors in your 2.4L equipped Nissan Altima, or Frontier, or Xterra, you don't need any expensive tools.
Here's a basic list of tools you'll need:
- A multimeter.
- You'll only be using the multimeter to check resistance (Ohms).
- If you need to upgrade or buy a multimeter, check out my recommendation: Buying A Digital Multimeter For Automotive Diagnostic Testing (found at: easyautodiagnostics.com).
- Scan tool.
- To actually test the fuel injectors, you don't need a scan tool (since a scan tool can't dynamically test the fuel injectors). But, having one makes the whole process easier since you're able to retrieve any diagnostic trouble codes (DTCs) stored in the PCM memory.
- Don't have one? Check out my recommendation: Actron CP9580 Scan Tool Review.
- Pen and paper to write down your fuel injector resistance test results.
The Fuel Injector Test
To get the most accurate test result, from the info presented in this article, you need to test the fuel injectors on your Nissan Altima (or Frontier, Xterra) with the engine warmed up.
Now, in case your car doesn't start (as in it Cranks but Doesn't Start)... doing a fuel injector resistance test probably won't help you. If this is your situation, take a look at this section of this tutorial: My Nissan Doesn't Start.
You'll be using the image in the image viewer to know what fuel injector belongs to what engine cylinder.
OK, this is what you need to do:
To get started, you need to disconnect all 4 fuel injectors from their electrical connectors.
Once all of the fuel injectors are disconnected, test the resistance of each one with your multimeter in Ohms mode. You'll do this by probing the male spade terminals inside the fuel injector with the multimeter's test leads.
Continued in the next page...