How To Test The Fuel Pump (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon)

Testing the fuel pump, on the 1999-2006 V8 Chevrolet Silverado (Suburban, Tahoe) and GMC Sierra (Yukon, Yukon XL), isn't difficult at all.

A fuel pressure test gauge can easily be connected to the fuel system to find out if the fuel pump is bad or not.

In this tutorial, I'll explain how to do it in a step-by-step way.

You can find this tutorial in Spanish here: Cómo Probar La Bomba De Gasolina (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

Chevrolet:

• Silverado (1500, 2500):
  • 4.8L, 5.3L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Silverado (2500):
  • 6.0L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Suburban (1500):
  • 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Suburban (2500):
  • 6.0L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Tahoe:
  • 4.8L, 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006

GMC:

• Sierra (1500, 2500):
  • 4.8L, 5.3L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Sierra (2500):
  • 6.0L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Yukon:
  • 4.8L, 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Yukon XL (1500):
  • 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Yukon XL (2500):
  • 6.0L: 2000, 2001, 2002, 2003, 2004, 2005, 2006

Common Symptoms Of A Bad Fuel Pump

A fuel pump will generally fail in one of two ways. It'll either stop working completely (producing no fuel pressure) and cause an engine no-start problem.

Or the fuel pump will begin to fail and function only enough to start the vehicle but the engine will not run optimally. In this case, the fuel pump produces only enough fuel pressure to start the engine but not enough to drive the vehicle on the road.

These are the symptoms that you're going to see when the fuel pump has failed or is starting to fail:

• The engine cranks but does not start.
• The engine starts but stalls after a few seconds.
• The engine starts but as soon as you step on the accelerator pedal the engine stalls.
• Lack of power while driving the vehicle.
• Explosions can be 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 stored in the fuel injection computer's memory.

Where To Buy A Fuel Pressure Test Gauge

You can buy a fuel pressure test gauge just about anywhere and is one of the most important tools any serious DIY'er should have in his/her tool box.

The fuel pressure test gauge kit that'll connect to your Chevy or GMC pickup or SUV's Schrader valve and that I recommend for its low price and durability is the: Actron CP7838 Professional Fuel Pressure Tester.

All of the following fuel pressure test gauge kits will help test the fuel pump on your Chevrolet Silverado (Suburban, Tahoe) and GMC Sierra (Yukon, Yukon XL):

TEST 1: Testing The Fuel Pressure With A Fuel Pressure Test Gauge

As I mentioned at the beginning, testing the fuel pump simply involves connecting the fuel pressure test gauge to the fuel system.

The fuel pressure test gauge connects to the Schrader valve located on the fuel injector rail (passenger side of the intake manifold).

NOTE: If you don't have a fuel pressure tester, you can run down to your local auto parts store and buy one there. If you want to save some bucks on this purchase take a look at my recommendations here: Where To Buy A Fuel Pressure Test Gauge.

FUEL PRESSURE SPECIFICATION: The fuel pressure specification for the 1999-2006 4.8L, 5.3L, 6.0L Chevrolet Silverado (Suburban, Tahoe) and GMC Sierra (Yukon, Yukon XL) is 55 to 62 PSI. Flex fuel engines: 48-54 PSI.

These are the test steps:

1. 1

   Connect your fuel pressure tester to the Schrader valve.

2. 2

   Have your helper crank the engine while you observe the needle on the fuel pressure tester gauge.

3. 3

   The fuel pressure tester should give you a reading between 55 to 62 PSI.

Let's examine your test results:

CASE 1: The fuel pressure is within the indicated specification. This is the correct test result and it lets you know that the fuel pump is OK on your V8 Chevrolet Silverado (Suburban, Tahoe) and GMC Sierra (Yukon, Yukon XL).

CASE 2: You got 0 psi fuel pressure. This test result lets you know that the fuel pump is defective and is causing the engine to not start.

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.