Testing the fuel injectors on your 3.0L V6 equipped Dodge (Chrysler or Plymouth) vehicle can seem quite the challenge since the fuel injectors are under upper intake manifold plenum.
But, after removing the intake manifold plenum they can be easily tested with a simple multimeter and in this tutorial I'll explain how.
Now, if you're really not that sure you have a bad fuel injector causing a misfire on your 3.0L V6 equipped Chrysler (Dodge or Plymouth) vehicle, I have a specific diagnostic strategy that'll help you narrow down the problem.
Contents of this tutorial:
NOTE: This tutorial applies only to the indicated 3.0L V6 equipped vehicles listed in the Applies To: box on the right column.
You can find this tutorial in Spanish here: Cómo Probar Los Inyectores (1998-2000 3.0L Dodge/Plymouth Mini-Van) (at: autotecnico-online.com).
Symptoms Of A Bad Fuel Injector
The most common symptom a failed or clogged fuel injector will provoke is a misfire condition. This misfire can be felt when the engine idles and/or when your accelerating the vehicle down the road.
Why a misfire condition?.. you might ask. Well, this is due to the fact that each cylinder, in your 3.0L V6 engine, needs 3 things to produce power. These are fuel, spark and air.
So, if the fuel injector isn't atomizing the fuel correctly (clogged fuel injector) or it's failed and isn't injecting fuel at all, the cylinder that injector belongs to will misfire.
Here are a couple of other symptoms your vehicle may experience:
- Rough idle.
- Lack of power.
- Hesitation when you accelerate your 3.0L V6 equipped Dodge (Chrysler) down the road.
- On vehicles that are OBD II equipped, you'll see a misfire diagnostic trouble code (DTC):
- P0300: Random Cylinder Misfire.
- P0301: Cylinder #1 Misfire.
- P0302: Cylinder #2 Misfire.
- P0303: Cylinder #3 Misfire.
- P0304: Cylinder #4 Misfire.
- P0305: Cylinder #5 Misfire.
- P0306: Cylinder #6 Misfire.
Just to point out something you'll need to keep in mind, fuel injectors tend to fail in one of several ways:
- The fuel injector's internal coil winding shorts out or becomes ‘open’. This causes the fuel injector to stop injecting fuel.
- The fuel injector becomes clogged and doesn't atomize the fuel correctly.
- It comes on and does not turn off (due to electrical issues). In other words: it does not pulse on and off but stays on all of the time spraying a tremendous amount of fuel as soon as you turn the ignition key to the ON position.
Whether the fuel injector is fried internally or clogged, this tutorial will offer you some specific suggestions to help you narrow down the possible solution.
Checking The Injector's Internal Resistance
Before you start (and to avoid any unnecessary repairs), I recommend that you eliminate the ignition system and engine compression as the cause of the misfire condition. If you haven't already, take a look at the following section: How To Find The BAD Or Clogged Fuel Injector.
As I mentioned earlier, the upper intake manifold plenum has to be removed to access the fuel injectors. I don't include any R & R (remove and replace) info but I do have a few suggestions for you before you start here: Precautions When Removing the Upper Intake Plenum.
NOTE: Don't have a multimeter or need to upgrade yours? Check out my recommendation: Buying A Digital Multimeter For Automotive Diagnostic Testing.
Alright, here are the steps:
Disconnect the fuel injectors from their harness connectors.
NOTE: The illustration above will help you identify the cylinder # the fuel injector belongs to.
Place your multimeter in Ohms (Ω) mode and:
Measure the resistance of the fuel injector across its two male spade terminals with the multimeter test leads (see the illustration in the image viewer).
Write down the resistance value that your multimeter records for the specific fuel injector you're testing. The illustration above will help you identify the cylinder # the fuel injector belongs to.
Repeat steps 1 through 3 on the remaining fuel injectors.
NOTE: The 3.0L V6 fuel injector factory manual resistance specification is approximately: 10 to 16 Ohms.
Let's find out what your specific multimeter test results mean:
CASE 1: Your multimeter reports all fuel injector resistances are within specification. This tells that none are shorted or open internally and this is good news.
Here's why: If any one of the fuel injectors were shorted or open internally, the fuel injector would have registered a radically different resistance value on your multimeter. Since the resistance values for all 6 were uniform, this test result tells you that they are not defective.
CASE 2: Your multimeter reports a fuel injector with a completely different resistance value. This indicates that the fuel injector is BAD. Replace the fuel injector.