A fuel pump pressure test is the diagnostic test you need to figure out if the fuel pump is good or bad on your 2000-2003 2.2L Chevrolet S10 pickup or GMC Sonoma.
This tutorial explains how to perform the fuel pump pressure test step-by-step and how to interpret its results.
You'll quickly determine if the fuel pump is good or bad with your test results.
Contents of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar La Bomba De Combustible (2000-2003 2.2L Chevrolet S10, GMC Sonoma) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 2.2L Chevrolet S10 Pickup: 2000, 2001, 2002, 2003.
- 2.2L GMC Sonoma: 2000, 2001, 2002, 2003.
Symptoms Of A Bad Fuel Pump
The 2.2L engine in your Chevrolet S10 (GMC Sonoma) needs three things to start. These three things are:
- Air.
- Fuel.
- Spark.
As you've guessed it, the fuel pump is the component that supplies the fuel the engine needs to start.
Sooner or later, the fuel pump will wear out and fail. When it does, it'll cause one of two issues:
- An engine no-start problem.
- An engine performance problem.
In many cases, the fuel pump still works but delivers just enough fuel to keep the engine running. Once the engine is under load, engine performance suffers.
If the fuel pump is still working but not delivering the correct amount of fuel, you'll see one or more of the following symptoms:
- Engine takes longer than usual to start (extended cranking).
- Engine idle is very rough.
- Engine backfires thru' the intake manifold under load.
- Engine starts, then dies.
A fuel pump pressure test will help you confirm (or eliminate) the fuel pump is the cause of an engine no-start or engine performance problem.
Where To Buy A Fuel Pressure Test Gauge
You'll need a fuel pressure test gauge with the GM Schrader valve adapter to test the fuel pressure on your 2.2L Chevy S10 or GMC Sonoma. Here are my recommendations:
Using A Fuel Pump Pressure Tester To Test The Fuel Pump
To test the fuel pump's pressure on your 2.2L Chevrolet S10 (GMC Sonoma), you'll connect a fuel pump pressure tester to the Schrader valve located on the fuel injector rail.
The Schrader valve is located on the fuel injector rail between fuel injectors #3 and #4 (towards the engine's firewall). Photo 2 of 2 in the image viewer points to the Schrader valve's general location.
If the fuel pump has failed, you'll either see a fuel pressure value of 0 PSI or a value below the indicated fuel pressure specification.
2000-2002 2.2L Chevrolet S10 and GMC Sonoma fuel pressure specification:
- 41-47 PSI Key On With Engine Off.
- With Key On Engine Running, fuel pressure should drop 3 to 10 PSI.
2003 2.2L Chevrolet S10 and GMC Sonoma fuel pressure specification:
- 55-62 PSI Key On With Engine Off.
- With Key On Engine Running, fuel pressure should drop 3 to 10 PSI.
OK, these are the test steps:
- 1
Remove the plastic dust cap from the Schrader valve.
- 2
Place a shop towel around the Schrader valve.
The shop towel's job is to absorb any fuel that may leak when doing step 2. - 3
Connect the fuel pressure test gauge to the Schrader valve.
- 4
When ready, ask your helper to cycle the key ON and OFF but don't crank the engine while you observe the fuel pressure tester's gauge.
Check your connections for fuel leaks. Resolve any fuel leaks before continuing to the next step. - 5
Crank the engine and check the fuel pressure gauge.
- 6
Your fuel pressure gauge should register the specified fuel pressure.
Let's take a look at your fuel pressure test results:
CASE 1: The fuel pressure test gauge registered 0 PSI. This confirms that the no-start problem is caused by a lack of fuel.
This usually means that the fuel pump is bad and needs to be replaced.
CASE 2: The fuel pressure gauge registered the indicated fuel pressure specification. This fuel pressure gauge result lets you know that the fuel pump is working and delivering enough fuel to the fuel injectors.
If your Chevrolet S10 or GMC Sonoma's engine is not starting, you can conclude the fuel pump is not behind the no-start problem.
CASE 3: The fuel pressure gauge registered a fuel pressure way below the specification. This test result lets you know that the fuel pump is failing.
