How To Test The Fuel Pump (1997-2007 4.6L, 5.4L V8 Ford E150, E250, E350)

At some point, the fuel pump on your V8 equipped Ford E150 (E250 or E350) will kick the bucket and it'll either cause an engine no-start problem or an engine performance issue.

In this step-by-step tutorial, I'll explain how to test the fuel pump with a fuel pressure gauge. You'll quickly know whether the fuel pump is to blame for the engine's no-start or engine performance problem.

Also, I'll explain how you can use starting fluid to determine if the engine's no-start issue is due to not getting fuel

APPLIES TO: This tutorial applies to the following vehicles:

• 4.8L, 5.4L V6 Ford E150: 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007.
• 4.8L, 5.4L V6 Ford E250: 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007.
• 5.4L V6 Ford E350: 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007.

Common Symptoms Of A Bad Fuel Pump

A fuel pump will usually fail in one of two main ways:

• Low pressure problem: The fuel pump kinda works —it gets enough fuel to the engine to start it but fails to deliver the right amount to keep the engine running smoothly, especially when you stick it in Drive and put the pedal to the metal.
• No pressure problem: This is when the fuel pump quits entirely. It doesn't pump any fuel to the engine, leading to an engine no-start problem.

Although the following is not the most exhaustive list of symptoms of a bad or failing fuel pump, these are the most common ones you're going to see:

• Engine No Start: The engine cranks but does not start.
• Stalling After Start: The engine starts but stalls after a few seconds.
• Stalling On Acceleration: The engine starts but as soon as you step on the accelerator pedal, the engine stalls.
• No Power Under Load: Lack of power while driving the vehicle.
• Backfiring: Explosions (loud popping sounds) can be heard coming from the intake manifold when you step on the accelerator while the engine is under load.
• Check Engine Light : The check engine light is on, and lean air-fuel mixture trouble codes are stored in the fuel injection computer's memory.

Before we jump into the next part, I gotta point out that other parts can go fail and mimic a bad fuel pump. So, it's super crucial to check the fuel pump's pressure with a gauge before you rush to swap it out. And that's exactly what I'm gonna walk you through in this tutorial.

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'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 your Chevrolet Express or GMC Savana's fuel pump:

Safety Precautions To Take When Testing The Fuel Pump Pressure

Before you start your tests, remember to play it safe to avoid any accidents or surprises. Here are a couple of important precautions to take:

• Work With A Cold Engine: Work with a cold engine when testing the fuel pump's fuel pressure or using starting fluid to reduce the risk of burns and injuries. Additionally, working with a cold engine reduces the risk of accidental ignition of fuel vapors.
• Avoid Flames And Sparks: When working with fuel-related components, it's crucial to avoid any open flames, sparks, or sources of ignition. This includes smoking, using electrical equipment that could produce sparks, or working near any other potential ignition sources. Gasoline and starting fluid vapors are highly flammable and can ignite easily, leading to fires or explosions.
• Wear Protective Gear: Wear appropriate protective gear to protect yourself from potential fuel spills or accidents. This may include safety glasses to protect your eyes from fuel splashes, gloves to prevent skin contact with fuel or chemicals, and appropriate clothing to minimize exposure to fuel vapors.
• Have a Fire Extinguisher Nearby: Have a fire extinguisher nearby in case of an emergency. Make sure the fire extinguisher is rated for use with flammable liquids and that you know how to use it effectively.
• Follow Fuel Pressure Gauge Manufacturer Instructions: When using a fuel pressure gauge to test the fuel pump's fuel pressure, it's important to follow the manufacturer's instructions carefully. This ensures that the gauge is connected properly and that the testing procedure is conducted safely. Incorrect use of a fuel pressure gauge can lead to inaccurate readings.

Sticking to these safety tips will help you cut down on the chance of any mishaps, letting you do the fuel pressure check both effectively and without any worries.

Fuel Pressure Specifications

The following fuel pressure specifications apply to the 1997-2003 4.6L and 5.4L V8 Ford E150, E250, and E350:

Fuel Pressure With The Key On Engine Off
35-45 PSI.

Fuel Pressure With The Key On Engine Running
28-45 PSI.

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

The best way to really know how your fuel pump's doing is by using a fuel pressure test gauge to check its pressure.

Since the V8 Ford engine in your van comes equipped with a pressure test port right on the fuel rail, it's a breeze to check it.

This test port, usually referred to as the Schrader valve, is on the fuel injector rail that has the fuel supply and return lines hooked up to.

NOTE: You'll need a fuel pressure tester that can connect to the Schrader valve. If you don't have one, take a loot at my recommendations here: Where To Buy A Fuel Pressure Test Gauge.

These are the test steps:

1. 1

   Locate the Schrader valve on the fuel injector rail.

2. 2

   Remove the dust cap from the Schrader valve and place a shop towel under the general area of the Schrader valve.
   
   NOTE: The shop towel's job is to absorb and fuel that may leak when performing step 3.

3. 3

   Connect your fuel pressure tester to the Schrader valve.

4. 4

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

5. 5

   Your fuel pressure gauge should register:
   
   Engine Does NOT Start: 35-45 PSI.
   
   Engine Starts: 28-45 PSI.

Let's examine your test results:

CASE 1: The fuel pressure is within the indicated specification. This is the correct test result.

This test result confirms that the fuel pump in your Express (Savana) van is OK (functioning correctly).

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 a 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.

TEST 2: Using Starting Fluid To Diagnose A No-Start Condition

A starting fluid test is a quick and easy way to see if a lack of fuel is why the engine in your Ford van won’t start.

Now, it's not as spot-on as testing the fuel pump pressure with a fuel pressure test to find if the fuel pump is bad, but it's always been my first move for troubleshooting an engine that won't start.

I'm a big fan of this method because it lets me zero in on the problem fast, and then I back it up with a fuel pressure gauge test for confirmation.

IMPORTANT: To get the most accurate test result from your starting fluid test, it's important that you confirm that all eight cylinders are getting spark from their ignition coils or spark plug wires (ignition coil pack equipped engines). If you haven't checked for spark yet, definitely do that before you dive into the starting fluid test.

CAUTION: Just a heads-up for safety - don't spray starting fluid into the throttle body while the engine is turning over. You should spray it in first, and then start cranking the engine.

These are the test steps:

1. 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. 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. 3

   Have your helper crank the engine once the intake air duct is back on the throttle body.

4. 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, not even a few seconds. This test result tells you that a lack of fuel from the fuel pump IS NOT causing the engine's no-start problem.

I want to point out that this conclusion is true only if all spark plug wires are sparking.

CASE 2: The engine started but died after a few seconds. This test result tells you that the engine's no-start problem is caused by a lack of fuel.