How To Test The Fuel Injectors (1998-2000 2.0L SOHC Dodge/Plymouth Neon)

This tutorial will help you test the internal resistance of the four injectors in the 1998-2000 2.0L SOHC Dodge/Plymouth Neon.

Through this easy and simple test, you'll be able to determine if the injector is faulty and not injecting fuel.

You'll also find an explanation on how to start a diagnosis of the injectors, to find the one that's faulty or clogged.

NOTE: This tutorial only applies to the 2.0L SOHC engine (Single Overhead Camshaft).

You can find this tutorial in Spanish here: Cómo Probar Los Inyectores De Combustible (1998-2000 2.0L SOHC Neon) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

• 2.0L Dodge Neon: 1998, 1999, 2000.
• 2.0L Plymouth Neon: 1998, 1999, 2000.

Symptoms Of A Bad Fuel Injector

Fuel injectors usually fail in one of two ways. They can suffer from an internal short-circuit or open-circuit problem, causing them to stop injecting gasoline.

Or they get clogged and stop atomizing the gasoline properly. Both types of problems will affect engine performance.

These are the most common symptoms you'll see when one fails:

• Rough idle.
• Lack of power.
• The engine hesitates when you accelerate under load.
• Cylinder misfire trouble codes:
  • P0300: Random Cylinder Misfire.
  • P0301: Misfire In Cylinder #1.
  • P0302: Misfire In Cylinder #2.
  • P0303: Misfire In Cylinder #3.
  • P0304: Misfire In Cylinder #4.

The main focus of the test I'm going to explain specifically looks at fuel injectors with short-circuit or open-circuit problems in their internal winding. But I'm also gonna offer you a diagnostic strategy designed to identify clogged fuel injectors (in the subtitle: How To Find The Bad Or Clogged Fuel Injector)

Checking The Resistance Of The Fuel Injectors

The factory fuel injector resistance specification for the 1998-2000 2.0L SOHC Neon is 10 to 16 Ohms (Ω).

To check this resistance, your Neon should be at room temperature. In other words, the engine should be cold. Additionally, this resistance is checked with your multimeter set to its Ohms function.

Here are the test steps:

1. 1

   Disconnect the fuel injectors from their electrical connectors.
   
   NOTE: To identify which cylinder the fuel injector belongs to, see the illustration above with the cylinder numbers for the 2.0L Neon.

2. 2

   Set the multimeter to its Ohms (Ω) function.

3. 3

   Measure the fuel injector's resistance across its two male terminals with the multimeter probes (see the illustration above).

4. 4

   Record the resistance value that your multimeter shows for the specific fuel injector you're testing.
   
   The illustration above will help you identify the cylinder number to which the fuel injector belongs.

5. 5

   Repeat steps 1 to 3 for the remaining fuel injectors.
   
   NOTE: The resistance specification for the 2.0L Neon is: 10 to 16 Ohms.

Let's find out what your test results mean:

CASE 1: All fuel injector resistances are within the specified value. This is the expected and correct test result, and it tells you that none have an internal short-circuit or open-circuit problem.

If you suspect a clogged fuel injector (that the resistance test can't detect), proceed to the next section: How To Find The Faulty Or Clogged Fuel Injector.

CASE 2: One of the fuel injectors recorded a resistance value that's not within specification. This indicates that the fuel injector is faulty. Replace the fuel injector.

How To Find The Bad Or Clogged Fuel Injector

This section will provide you with a testing strategy to help you identify a bad or clogged fuel injector.

Even if the issue isn't injector-related, this guide will help you figure out the actual reason your Neon's engine is misfiring, especially if you're stumped on where to begin.

Don't worry. Finding the exact cause of the cylinder misfire (or rough idle) in your 2.0L Neon isn't complicated. Let's get started:

1. First, find the 'dead' cylinder.
   • This is the most important first step. You can do this by connecting an automotive scan tool (or code reader) and reading the fault codes stored in your Neon's fuel injection computer's memory.
2. After identifying the 'dead' cylinder, make sure it's receiving spark.
   • It's important to check for spark using a spark tester.
     • You can find this test explained step-by-step here: How To Test The DIS Ignition Coil (Chrysler 2.0L, 2.4L) (at easyautodiagnostics.com).
   • Make sure that the dead cylinder's spark plug boot and the spark plug are NOT soaked (or swimming) in engine oil.
   • You should also remove the spark plugs and check for cracks or carbon tracks (this is VERY important).
     • Here's a real-life case study on carbon tracks and how they can cause cylinder misfire: Carbon Tracks Are A Common Cause Of Ignition Misfires (at: easyautodiagnostics.com).
3. If the 'dead' cylinder is getting spark, the next step is to make sure it has good compression.
   • After ensuring the 'dead' cylinder's spark plug wire is delivering spark, you need to check for a low compression issue.
   • This is one of the most overlooked tests when diagnosing a cylinder misfire or rough idle. You can find the test here:
     • How To Test The Engine Compression (Chrysler 2.0L, 2.4L).
4. If the 'dead' cylinder has spark and good compression, the next step is to test the fuel injector's activation signal with a Noid light.
   • If every test gives you the correct and expected result, the next step is to make sure the fuel injector is receiving its activation signal.
   • The following tutorial on how to use a Noid light explains how to check for the fuel injector activation signal: (I know this isn't the most detailed article on the topic, but it should give you an idea of what's involved).
     • How To Use A Noid Light And Where To Buy It (at: easyautodiagnostics.com)
5. If the 'dead' cylinder has spark, good compression, and the fuel injector is being activated; the next step is to swap the fuel injector.
   • If I find that I have a specific 'dead' cylinder and:
     1. The ignition system isn't behind the issue.
     2. The compression value of that cylinder is fine (compared to the rest of the cylinders).
     3. The fuel injector's resistance is fine and it's being activated by the fuel injection computer...
     4. I think the fuel injector is clogged, I then swap that fuel injector with an adjacent one.
     If the cylinder failure now follows that swap, I now know that the fuel injector is clogged (or faulty) and needs to be cleaned or replaced.

Diagnosing a fuel injector problem in your Dodge Neon may seem challenging, but it's all about a process of elimination. Meaning that if one test says a part's fine, you move to the next. It's the same approach a pro mechanic/technician takes, and now you can do it yourself.