In this tutorial, I'll explain how to test the fuel pump's pressure with a fuel pressure test gauge on the 1992-1993 3.3L V6 Pontiac Grand Am.
I'll also explain how to do a starting fluid test to check to see if the no-start problem is due to a lack of fuel.
Contents of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar La Bomba De Combustible (1992-1993 3.3L V6 Pontiac Grand Am) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 3.3L V6 Pontiac Grand Am: 1992, 1993.
Symptoms Of A Bad Fuel Pump
Over the years that I've been working on cars, I've seen that fuel pump failures usually cause one of two types of problems:
- Either the engine will not start.
- - or -
- The engine starts and runs, but runs very badly.
If your 3.3L V6 Pontiac Grand Am's engine starts and runs, but the fuel pump is failing -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.
Both types of failures can easily be diagnosed with a simple fuel pump pressure test.
Where To Buy A Fuel Pressure Test Gauge
You'll need a fuel pressure test gauge and a quick disconnect adapter to test the fuel pressure on your 3.3L V6 Pontiac Grand Am (since the fuel rail doesn't have a Schrader valve).
You'll also need a quick disconnect tool to disconnect the fuel line (to insert the adapter).
The following kits include the tools you need:
Using A Fuel Pump Pressure Tester To Test The Fuel Pump
As mentioned earlier, to test the fuel pump pressure you're going to need a fuel pressure test gauge and a quick disconnect adapter (to connect the gauge to your 3.3L V6 Pontiac Grand Am's fuel system).
You're also going to need a quick disconnect tool to be able to disconnect the fuel line from the fuel injector rail. This tool is also going to come in handy when it's time to disconnect the fuel pressure test gauge from the fuel line.
In photo 1 of 3, the orange arrow points to the fuel line you need to disconnect to install the fuel pressure test gauge adapter.
Photo 2 of 3, you'll see an example of the fuel pressure test gauge and the quick disconnect adapter you'll need for the fuel pump pressure test.
Photo 3 of 3, shows the quick disconnect tools you'll need to disconnect the fuel line from the fuel injector rail (to install the test gauge's adapter).
NOTE: If you don't have a fuel pressure tester with the correct adapter or don't have the quick disconnect tool, take a look at this section: Where To Buy A Fuel Pressure Test Gauge.
The fuel pump pressure for the 1992-1993 3.3L V6 Pontiac Grand Am is:
- 40-47 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:
Place a shop towel around the fuel pressure line (where it connects to the fuel injector rail).
The shop towel's job is to absorb any fuel that may leak when doing step 2.
Disconnect the fuel pressure line from the fuel injector rail.
NOTE: You'll need to use a quick-disconnect tool to disconnect the fuel pressure line from the fuel injector rail.
Connect the test adapter between the fuel pressure line and the fuel injector rail.
Connect the fuel pressure gauge to the adapter.
When ready, ask your helper to cycle the key ON and OFF several times but don't crank the engine while you observe the fuel pressure tester's gauge.
Check your connections for fuel leaks.
Crank the engine and check the fuel pressure gauge.
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. You can conclude the fuel pump is OK and 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.