How To Test A Fuel Injector (Chrysler 2.0L, 2.4L)

Continued from the previous page.

1. 3

   Probe the fuel injectors two male spade terminals with the multimeter test leads.
   
   In case you're wondering, it doesn't matter which test lead (black or red) you use on which terminal on the fuel injector, since the polarity doesn't matter in a simple resistance test.

2. 4

   Write down the Ohms (resistance) value that your multimeter is registering on a piece of paper. Write down what engine cylinder that fuel injector belongs to, too.

3. 5

   The fuel injector resistance value will be around 11-18 Ohms. On your particular 2.0L (SOHC, DOHC) or 2.4L (DOHC), the actual value your multimeter registers might be a different. Don't fret over this and you'll see why when you interpret the resistance value of all four.
   
   Now, repeat the above steps on the remaining fuel injectors.

Interpreting The Results Of The Fuel Injector Test

Let's find out what your specific multimeter test results mean for your Neon (or Stratus, or Voyager, or Caravan, or Breeze, etc):

CASE 1: All four fuel injectors registered the same resistance values. This confirms that the fuel injector your are testing is OK.

Here's why: If any one of the fuel injectors were bad, your multimeter would've registered a completely different resistance value for that fuel injector. Since your resistance (Ohms) value were the same for all then this is an indication that the fuel injectors do not have an internal electrical fault.

CASE 2: One of the four fuel injectors registered a completely different resistance value. This indicates that the fuel injector is bad. Replace the fuel injector.

Which Fuel Injector Do I Test First? Or Do I Test All Of Them?

You don't have to test them all, if you don't have to. This is especially true if you have a repair manual for your specific Chrysler 2.0 (SOHC, DOHC) or 2.4L (DOHC) and that repair manual has the fuel injector resistance specification.

The main reason I suggest you test them all is to avoid having to search for the resistance value, either online or in a book. Now, don't get me wrong, the more info you have at your disposal, the better. But, if you test them all then you'll find out what the average Ohms value is without having to look it up.

My Personal Testing Suggestions

Finding the bad fuel injector is not hard to do if you have a specific diagnostic strategy. In this section, I'm gonna' share with you the way I diagnose a bad fuel injector (and of course, you can modify my testing suggestion to fit your specific needs).

I first start by:

1. Check for misfire trouble codes.
   • You won't always have a specific bad fuel injector code, but you'll definitely have a misfire code (around 90% of the time that is).
2. Check the ignition system for spark.
   • Before I even start thinking that I may have a bad fuel injector, I make sure that every engine cylinder is getting spark.
   • I check that each spark plug wire is feeding spark to the spark plug.
   • I check that the spark plug wire boot and spark plug are NOT soaked (or swimming) in engine oil.
   • I remove the spark plugs and check them for cracks or carbon tracks (this is SO important).
     • Here's a real life case study on carbon tracks and how they can cause a misfire: Carbon Tracks Are A Common Cause Of Ignition Misfires (at: easyautodiagnostics.com).
   • You can find an in-depth step-by-step tutorial on how to test the ignition system here: How To Test The Ignition Coil Pack (Chrysler 2.0L, 2.4L) (this info is found at: easyautodiagnostics.com).
3. Check engine compression.
   • After making sure that the ignition system and all its components are OK, I check for low engine compression.
   • This is one of the most overlooked tests when diagnosing a misfire or rough idle condition.
   • You can find the test here: How To Test The Engine Compression (Chrysler 2.0L, 2.4L).
4. Noid Light Test.
   • If every test above checks out OK, I do a fuel injector Noid light test.
   • The Noid light test will help you make sure that the fuel injector is getting activated.
   • The following Noid light article/tutorial may help you: How To Use A Noid Light And Where To Buy It (I know that this is not the most in-depth article on the subject, but it should give you an idea of what is involved).

The above testing strategy may seem like overkill or too difficult but it isn't. Most of the above tests can be done pretty fast and are not hard to do.

I can tell you from experience that the way to save yourself the frustration of replacing good parts, your vehicle doesn't need and that don't solve the problem, is testing everything. Thankfully, there's a test for just about anything on your car!