How To Test The Fuel Pump (2001-2003 4.2L V6 Ford E150, E250)

Testing the fuel pump output pressure with a fuel pressure test gauge is the go-to method to determine if the fuel pump is functioning properly, failing, or has already failed.

In this tutorial, I’ll explain how to perform the fuel pump pressure test on the 2001-2003 4.2L V6 Ford E-Series van. I'm also providing the fuel pump pressure specifications so you can assess whether the pump is performing as it should.

I'm also gonna explain how to use starting fluid to check if a lack of fuel is the reason the engine won't start.

APPLIES TO: This tutorial applies to the following vehicles:

• 4.2L V6 Ford E150: 2001, 2002, 2003.
• 4.2L V6 Ford E250: 2001, 2002, 2003.

NOTE: If you need to see the fuel pressure test for the 1997-2000 4.2L V6 Ford E150 (E250), go here:

• How To Test The Fuel Pump (1997-2000 4.2L V6 Ford E150, E250).

Common Symptoms Of A Bad Fuel Pump

Typically, a fuel pump is going to fail in one of two ways:

• Low pressure issue: The fuel pump works just enough to send fuel to start the engine but not enough to keep it running optimally under load.
• No pressure issue: In this scenario, the fuel pump assembly stops working and doesn't send any fuel to the engine causing it not to start.

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 go to the next section, I just want to highlight that other components can fail and cause similar issues, just like a bad fuel pump. So, it's really important to test the fuel pump's pressure with a gauge before you decide to change it, and that's what I'll show you how to do.

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 Ford van'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 Ford E-Series van'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.

By following these safety measures, you can minimize the risk of accidents and perform the pressure check effectively and safely.

Fuel Pressure Specifications

The following fuel pressure specifications apply to the 2001-2003 4.2L V6 Ford E150 and E250:

Fuel Pressure With The Key On Engine Off
35-55 PSI.

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

What makes testing the fuel pump with a fuel pressure test gauge a pretty easy affair is the fact that Ford thoughtfully installed a fuel pressure test port on the fuel injector rail.

Although this test port (called a Schrader valve) is somewhat hidden by the upper intake manifold, it's located on the fuel injector rail that feeds cylinders 4, 5, and 6 (bank 2 -on the driver's side of the engine). This rail is where the fuel pressure line connects.

If the fuel pump has failed, you will generally see a fuel pressure of 0 psi. If the fuel pump is failing, you will see a fuel pressure below the specified values.

IMPORTANT: If you haven't already done so, check the fuel pump inertia switch first. See: Fuel Pump Inertia Switch Check.

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

   Disconnect the ignition coil from its electrical connector.
   
   The fuel pump is tested with the key on engine off (KOEO) and disconnecting the ignition coil will keep the engine from starting.

2. 2

   Locate the Schrader valve on the fuel injector rail crossover line (see photos above).

3. 3

   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.

4. 4

   Connect your fuel pressure tester to the Schrader valve.

5. 5

   Have your helper crank the engine and then let go of the key while you observe the needle on the fuel pressure tester gauge.
   
   NOTE: What you want to do is crank the engine by turning the ignition key and then letting it go. The key should automatically stay in the ON position after you let go, and that’s exactly where we need it to be. Since the ignition coil is unplugged, the engine won't actually start up.

6. 6

   Your fuel pressure gauge should register 35-55 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 Ford 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.

Using Starting Fluid To Diagnose A No-Start Condition

One of the fastest ways to determine if a lack of fuel, like one caused by a bad fuel pump, is preventing the engine from starting is to use starting fluid.

The starting fluid test simply involves spraying starting fluid into the throttle body's bore and then having a helper crank the engine.

If the engine starts and runs, it indicates that the engine isn't getting fuel. If the engine doesn’t start, then a lack of fuel is not the reason for the engine's failure to start.

I do want to point out that if a lack of fuel is the issue, when you spray starting fluid into the throttle body, the engine will only run until the starting fluid you sprayed is consumed.

IMPORTANT: To achieve the most accurate result from your starting fluid test, make sure all 6 cylinders are getting spark. If you haven't checked for spark yet, do so before proceeding with the starting fluid test.

CAUTION: As a safety precaution, you should never spray starting fluid into the throttle body while the engine is cranking. Instead, you should first spray starting fluid into the throttle body and then crank 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.

Fuel Pump Inertia Switch Check

Your Ford E-Series van is outfitted with a fuel pump inertia switch and it's located behind the plastic kick panel on the passenger side of the van. It's job is to cut off power (or ground) to the fuel pump when an impact occurs.

If the fuel pump inertia switch is triggered, the engine won’t start or it will stall if already running, due to fuel cutoff.

While this switch is primarily meant to activate during a pretty significant impact, such as in a car crash, it can sometimes be triggered by lighter bumps.

Since a light bump can trigger it, it’s important to always check and reset the inertia switch as part of any fuel pump testing process.

To reset it, simply press down firmly on the button at the top of the switch until it clicks into place.

More 4.2L Ford E150 And E250 Test Tutorials

If this tutorial was helpful, be sure and take a look at all of the 4.2L V6 E150 and E250 diagnostic tutorials in this index:

• 4.2L Ford E150 And E250 Index of Articles.

Here's a sample of the tutorials you'll find there:

• How To Test The Throttle Position Sensor (1997-2000 4.2L V6 Ford E150, E250).
• How To Test Engine Compression (1997-2003 4.2L V6 Ford E150, E250).
• How To Test The CKP Sensor With A Multimeter (1997-2003 4.2L V6 Ford E150, E250).
• How To Test For A Blown Head Gasket (1997-2003 4.2L V6 Ford E150, E250).