This tutorial will explain how to test the fuel pump on the 2007-2008 2.2L Chevrolet Malibu.
Testing the fuel pump on this specific 2.2L Chevrolet Malibu is a breeze because the Schrader valve is very easy to access.
NOTE: The Schrader valve is pictured above and this is where the fuel pressure tester is connected to to be able to get a fuel pump pressure reading.
Contents of this tutorial at a glance:
Puedes encontrar este tutorial en Español aquí: Cómo Probar La Bomba De Combustible (2007-2008 2.2L Chevrolet Malibu) (en: autotecnico-online.com).
Symptoms Of A Bad Fuel Pump
Fuel pumps usually fail in one of two ways. Either the fuel pump stops working completely and the engine cranks but does not start.
Or the fuel pump supplies just enough fuel to start the engine but not enough to be able to drive the vehicle on the road.
The cool thing is that both of these conditions can be easily tested by connecting a fuel pressure test gauge to the Schrader valve on the fuel injector rail and seeing if the fuel pressure is within the factory specification.
When the fuel pump fails you're going to see one or more of the following symptoms:
- The engine cranks but does not start.
- The engine starts but stalls after a few seconds.
- The engine starts but idles rough.
- The engine starts but as soon as you step on the accelerator pedal the engine stalls.
- Lack of power while driving the vehicle.
- Popping-like sound heard coming from the intake manifold when you step on the accelerator while the engine is under load.
- The check engine light is on and lean air fuel mixture trouble codes are stowed in the fuel injection computer's memory (P0171: Fuel System Too Lean).
TEST 1: Testing The Fuel Pressure With A Fuel Pressure Test Gauge
As I mentioned before, what makes testing the fuel pump on the 2007-2008 2.2L Chevrolet Malibu easy is the fact that the Schrader valve is very accessible.
You're going to need a fuel pressure test gauge and if you don't have one, you can run down to your local auto parts store and you can rent or buy one there.
If you'd like to buy one and save a few bucks, check out my recommendations here: Where To Buy A Fuel Pressure Test Gauge.
The fuel pressure specification that'll let you know that the fuel pump is OK is: 50 to 60 PSI. This fuel pressure specification applies whether the engine is not starting or the engine is starting and running.
If the fuel pressure is below this range, then you can conclude that the fuel pump is failing and needs to be replaced.
If the fuel pressure is within the indicated specification then you can conclude that the fuel pump is OK (not defective).
These are the test steps:
Remove the air cleaner assembly from the throttle body to access the Schrader valve which is located on the fuel injector rail.
Place a shop towel around the Schrader valve. This will soak up any fuel that spills as you install the fuel pressure test gauge.
Connect your fuel pressure tester to the Schrader valve.
Have your helper crank the engine while you observe the needle on the fuel pressure tester gauge.
The fuel pressure tester should give you a reading between 50 to 60 PSI.
Let's examine your test results:
CASE 1: The fuel pressure is within the indicated specification. This is the correct and expected test result. It lets you know that the fuel pump is working correctly.
CASE 2: You got 0 psi fuel pressure. This usually lets you know that the fuel pump is defective and needs to be replaced.
Before you replace the fuel pump make sure that the fuel pump relay and fuel pump fuse are supplying power to the fuel pump when the engine is being cranked. If battery power is available to the fuel pump, when cranking the engine, then you can confidently conclude that the fuel pump is defective and that it needs to be replaced.
CASE 3: The fuel pressure was below the indicated fuel pressure specification. This test result lets you know that even though the fuel pump is supplying some fuel it's not supplying enough to have the engine run optimally.
This is an indication that the fuel pump is failing and needs to be replaced.