I have recently picked up a GM Tech2 scan tool and wanted to go thru some of the tests on my car. Mostly to become familiar with the tool and its hardware parts, software menus, etc.. Hopefully at the same time I am verifying the health of my Cadillac XLR-V. On my V I had to remove the intake plumbing to attach the fuel pressure gauge to the fitting on the driver side fuel rail. You can only run thru the 8 injectors with this test once. Then you need to start/stop the engine before running it again. Reason being you don’t want to load up the cyls with too much un-burnned fuel. I wrapped a rag around the fitting for the pressure gauge when disconnecting because it will spit out some fuel when you remove it.
You might see these symptoms that would lead you to want to run this test (listed on the web). All from erratic fuel injector behavior:
The Engine Misfires (Check Engine/DTC codes may be present, but not always)
Idling Gets Rough
Your Gas Mileage Tanks
The Tach RPM Needle Starts to Dance
Worse Case: Your Car Won’t Start
I also think if you did have one or more clogged injectors in a bank, you will see the long-term fuel trim (LTFT) for that bank higher than you would expect. This would be because the ECU will try to compensate for the overall lean situation, which it controls at the bank level.
Cadillac XLR GM Tech 2 Fuel Injector Balance Test Display
