A fuel injector resistance test can easily determine if a fuel injector on your Dodge Neon (or Stratus or PT Cruiser or Cirrus or Breeze, etc) is defective or not. This test doesn't require that you use expensive testing equipment, since a simple multimeter will suffice.
A bad fuel injector will cause your Neon (or any 2.0L (SOHC, DOHC), 2.4L (DOHC) equipped Chrysler vehicle) to idle rough, run rough, and light up the check engine light with either misfire codes (P0300, P0301, P0303, P0304) or fuel injector diagnostic trouble codes (P0201, P0202, P0203, P0204).
Contents of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar Los Inyectores De Combustible (Chrysler 2.0L, 2.4L) (at: autotecnico-online.com).
Symptoms Of A Bad Fuel Injector
The most common and obvious symptom of a bad fuel injector will be that your car's engine will have a rough idle and an engine miss when you accelerate it down the road.
What really stinks is that the PCM won't always set a specific fuel injector trouble code. But if it does, you'll see one of the following:
- P0201: Injector #1 Control Circuit.
- P0202: Injector #2 Control Circuit.
- P0203: Injector #3 Control Circuit.
- P0204: Injector #4 Control Circuit.
From personal experience over the years, what's really interesting is that around 90% of the time, when you do have a bad fuel injector, you'll see a misfire trouble code:
- P0301: Cylinder #1 Misfire.
- P0302: Cylinder #2 Misfire.
- P0303: Cylinder #3 Misfire.
- P0304: Cylinder #4 Misfire.
And well the other symptoms your vehicle may experience are:
- Lack of power.
- Bad gas mileage.
- Check engine light is on.
What Tools Do I Need To Test The Fuel Injectors?
To test the fuel injectors in your Chrysler 2.0L or 2.4L equipped car 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: Abe's Scan Tool Recommendation.
- Pen and paper to write down your fuel injector resistance test results.
The Fuel Injector Test
The best way to do this test is with the engine in your Stratus (or Cirrus, or PT Cruiser, or Voyager, etc.) slightly warmed up. If your car has been running for a while and it's hot, let it cool down for about an hour. If it's completely cold then crank up the engine and let it warm up for about 20 minutes.
Although having the engine warmed up helps to get a more accurate snapshot of the condition of the fuel injectors, it's not that critical.
The reason I mention this is that you may have the fuel injectors already off of the car, or the car may not start, etc. So, if this is your case, you don't have to install the fuel injectors and start the engine to warm her up. You can test them cold.
Some vehicles (like the PT Cruiser) require that the intake manifold's plenum be removed to gain access to the fuel injectors. If this is the case in your particular 2.4L (DOHC) vehicle, please read this section: Important Tips.
Alright, here are the steps:
Unplug all four fuel injectors from their electrical connectors.
Grab your multimeter and place it in Ohms mode.
Continued in the next page.