Testing the fuel injectors of the 2004, 2005, and 2006 3.5L V6 Chevy Malibu can seem quite impossible, since they're located underneath the intake manifold plenum.
But nothing could be further from the truth because you don't have to remove the intake plenum to test them. In this tutorial, I'll explain how to do it.
Contents of this tutorial at a glance:
You can find this tutorial in Spanish here: Cómo Probar Los Inyectores (2004-2006 3.5L Chevrolet Malibu) (at: autotecnico-online.com).
NOTE: You can find the fuel injector tests for the 2007-2008 3.5L Chevrolet Malibu here: How To Test The Fuel Injectors (2007-2008 3.5L Malibu).
Symptoms Of A Bad Fuel Injector
The OBD2 system on your 3.5L Chevy Malibu is designed to set a fuel injector trouble code when one of them fails.
If the computer does set a fuel injector trouble code, you will see one or several of the following:
- P0201: Injector 1 Control Circuit.
- P0202: Injector 2 Control Circuit.
- P0203: Injector 3 Control Circuit.
- P0204: Injector 4 Control Circuit.
- P0205: Injector 5 Control Circuit.
- P0206: Injector 6 Control Circuit.
In the majority of the cases, the fuel injection computer will not set a fuel injector trouble code but a cylinder misfire trouble code. When this happens you'll see one or more of the following:
- 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.
Besides a fuel injector or cylinder misfire trouble code, you're also going to notice one or more of the following symptoms:
- Rough idle.
- Bad gas mileage.
- A heavier than usual exhaust gas smell coming out of the tailpipe.
- Lack of power when accelerating the vehicle under load.
Location Of The Fuel Injector Harness Connector
As you're already aware, the fuel injectors are located underneath the intake manifold plenum. The really awesome thing is that you don't have to remove it to test them.
What we'll do is test the resistance of each fuel injector from the fuel injector harness connector.
On the 2004-2006 3.5L Chevy Malibu, the fuel injector harness connector is located right above spark plug number 2 (see photo 1 of 3 above).
We'll be performing our tests on the connector that belongs to the fuel injector harness itself. This connector has male spade terminals as you can see in photo 2/3 and photo 3/3 in the image viewer above.
Where To Buy The Fuel Injectors And Save
The following links will help you comparison shop for the fuel injectors:
Not sure if the fuel injector will fit your particular GM vehicle? Don't worry, once you get to the site, they'll make sure it fits. If it doesn't, they'll find you the right one.
TEST: Testing The Fuel Injector Resistance
The fuel injector resistance specification is 11 to 14 Ohms with a cold engine.
If a fuel injector's internal coil winding is fried, then it's going to have a radically different resistance value than the specification.
These are the test steps:
- 1
Place your multimeter in Ohms mode.
- 2
Disconnect the fuel injector harness from the engine wiring harness connector.
NOTE: All tests are done on the fuel injector harness connector which has male spade terminals. - 3
Probe terminals A and C with the multimeter test leads to test injector #1.
Your multimeter should register 11 to 14 ohms. - 4
Probe terminals A and D with the multimeter test leads to test injector #2.
Your multimeter should register 11 to 14 ohms. - 5
Probe terminals A and E with the multimeter test leads to test injector #3.
Your multimeter should register 11 to 14 ohms. - 6
Probe terminals A and F with the multimeter test leads to test injector #4.
Your multimeter should register 11 to 14 ohms. - 7
Probe terminals A and G with the multimeter test leads to test injector #5.
Your multimeter should register 11 to 14 ohms. - 8
Probe terminals A and H with the multimeter test leads to test injector #6.
Your multimeter should register 11 to 14 ohms.
Let's examine your test results:
CASE 1: The resistance of all 6 fuel injectors is within specification. This is the correct and expected test result and confirms that the fuel injectors are not defective internally.
CASE 2: One or more fuel injectors' resistance value is not within specification. This let you know that that fuel injector or fuel injectors are defective internally and need to be replaced.