In this tutorial, I'm going to explain how to test the fuel pump with a fuel pressure test gauge on the 1995-1999 3.1L V6 Chevy Lumina and Monte Carlo.
With your test results, you'll be able to easily find out if the fuel pump is bad or not.
I've also included the test instructions on how to test a lack of fuel with starting fluid.
Contents of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar La Bomba De Combustible (1995-1999 3.1L V6 Chevrolet Lumina, Monte Carlo) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 3.1L Chevrolet Lumina: 1995, 1996, 1997, 1998, 1999.
- 3.1L Chevrolet Monte Carlo: 1995, 1996, 1997, 1998, 1999.
FUEL PUMP CIRCUIT WIRING DIAGRAMS:
- Fuel Pump Wiring Diagram (1995 3.1L V6 Chevrolet Lumina, Monte Carlo).
- Fuel Pump Wiring Diagram (1996 3.1L V6 Chevrolet Lumina, Monte Carlo).
- Fuel Pump Wiring Diagram (1997 3.1L V6 Chevrolet Lumina, Monte Carlo).
- Fuel Pump Wiring Diagram (1998-1999 3.1L V6 Chevrolet Lumina, Monte Carlo).
Symptoms Of A Bad Fuel Pump
The fuel pump will usually fail in one of two ways:
- It will stop sending fuel to the fuel injectors and the engine won't start.
- It'll send just enough fuel to start the engine but the engine will run with serious drivability issues.
When the fuel pump sends barely enough fuel to start and keep the engine running, you'll see one or more of the following problems:
- Rough idle.
- Engine takes a long time to start (extended cranking time).
- Lack of power when accelerating the vehicle down the road.
- Engine backfires through the intake manifold when accelerating the vehicle down the road.
- Lean air fuel mixture trouble code: P0171: Fuel System Too Lean.
If you're troubleshooting an engine no-start condition and need more help, check out the following guide. It walks you through additional tests and tips that'll point you in the right direction:
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 Lumina or Monte Carlo's Schrader valve and that I recommend for its low price and durability is the: BETOOLL 0-140 PSI Fuel Pressure Tester.
All of the following fuel pressure test gauge kits will help test your Chevy Lumina or Monte Carlo's fuel pump:
Disclosure: As an Amazon Associate, I earn from qualifying purchases. Buying through these links helps support this site at no extra cost to you. Thanks for your support —it really means a lot!
TEST 1: Checking Fuel Pressure With A Fuel Pressure Gauge
The most accurate way to test the fuel pump on your 3.1L Chevrolet Lumina (Monte Carlo) is to use a fuel pump pressure tester.
We'll connect the fuel pump pressure tester to the Schrader valve (see photo above) which is located on the fuel injector rail. To be a bit more specific, it's located between the alternator and the power steering pump reservoir.
NOTE: If you don't have a fuel pressure test gauge, you can run down to your local auto parts store and buy one there. You can also buy one online. Check out my recommendations here: Where To Buy A Fuel Pressure Test Gauge.
FUEL PRESSURE SPECIFICATION:
- 41-47 PSI Key On With Engine Off.
- With Key On Engine Running, fuel pressure should drop 3 to 10 PSI.
These are the test steps:
- 1
Place a shop towel around the Schrader valve.
- 2
Connect a fuel pressure gauge to the Schrader valve on the fuel rail.
- 3
When ready have your helper crank the engine while you observe the fuel pressure tester gauge.
- 4
The fuel pressure tester should register:
If engine doesn't start: 41-47 PSI.
If engine starts: fuel pressure should drop 3 to 10 PSI.
Let's examine your test results:
CASE 1: The fuel pressure gauge registered 0 PSI. This test result lets you know that the fuel pump is not supplying fuel to the engine. Without fuel, the engine is not going to start.
If the engine in your Chevy Lumina (Monte Carlo) cranks but does not start, then you can conclude that the reason behind this is a defective fuel pump.
CASE 2: The fuel pump registered a pressure way below the specified range but not 0 PSI. This lets you know that the fuel pump is defective.
If the fuel pump is not supplying enough fuel to the engine, the engine may start and run but it'll run badly. In these cases you'll see one or more of the following:
- The engine will start and run but as soon as your put the transmission in Drive and accelerate, the engine stalls.
- The engine starts and runs, but you hear explosions coming from the intake manifold when you accelerate the engine.
- Lean air/fuel mixture trouble codes lighting up the check engine light.
CASE 3: The fuel pump registered a pressure within the specified range. This lets you know that the fuel pump is working within normal parameters. In other words, it's not defective.
If your 3.1L Chevrolet Lumina (Monte Carlo) is cranking but not starting, you can conclude that it's not due to a defective fuel pump. See the following tutorial for additional test and tips to point you in the right direction:
TEST 2: Using Starting Fluid To Diagnose A No-Start Condition
Using starting fluid to see if the engine is not starting due to a lack of fuel is a very ancient test that automotive mechanics have been using since the age of carburetors.
The starting fluid test is not the most accurate way of testing a bad fuel pump, but can pinpoint a no-start problem to a lack of fuel.
This is probably the first test I perform when testing a 'cranks but does not start' problem.
IMPORTANT: For this test to give you an accurate test result, you need to make sure that all six cylinders are getting spark.
These are the test steps:
- 1
Remove the intake air duct from the throttle body. You don't have to completely remove it, since you'll have to reconnect it in step 2.
- 2
Spray starting fluid down the bore of the throttle body. After spraying a good squirt of starting fluid, quickly reconnect the air duct to the throttle body (you don't have to tighten the hose clamp).
- 3
Have your assistant crank the engine once the intake air duct is back on the throttle body.
- 4
You'll get one of two results with this test:
1.) The engine will start momentarily and after a few seconds will die.
2.) The engine will only crank but not start at all.
OK, let's find out what your results mean:
CASE 1: The engine did not start at all. This test result confirms that the no-start condition is NOT due to a lack of fuel from the fuel pump.
Remember, this test result is only valid if you have confirmed that all spark plug wires are sparking.
CASE 2: The engine started but died after a few seconds. This test result tells you that your 3.1L Chevy Lumina or Monte Carlo's no-start condition is being caused by a lack of fuel.
More 3.1L V6 Chevrolet Lumina (Monte Carlo) Diagnostic Tutorials
You can find a complete list of 3.1L V6 Lumina and Monte Carlo diagnostic test tutorials in this index:
Here's a list of articles you'll find there:
- How To Test The Engine Compression (3.1L V6 Chevrolet And Pontiac Vehicles).
- How To Test The Fuel Injectors (1995-1999 3.1L Chevrolet Lumina, Monte Carlo).
- How To Test The 24X Crankshaft Position Sensor (1995-1999 3.1L V6 Chevrolet Lumina, Monte Carlo).
- Fuel Pump Wiring Diagram (1998-1999 3.1L V6 Chevrolet Lumina, Monte Carlo).
If this info saved the day, buy me a beer!
