How To Test The Fuel Pump (1990-1999 3.0L V6 Ford Taurus, Mercury Sable)

How To Test The Fuel Pump (1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999 3.0L V6 Ford Taurus, Mercury Sable)

The fuel pump, in your 3.0L Ford, can be easily tested with an inexpensive fuel pressure test gauge. This is due to the fact that your 3.0L V6 equipped Ford Taurus (Mercury Sable) comes equipped with a Schrader valve and it's to this valve that the fuel pressure test gauge is connected to.

In this tutorial I'm also gonna' explain the simple 'starting fluid' test, which is a quick way to confirm a lack of fuel problem causing a no-start problem.

ES In Spanish You can find this tutorial in Spanish here: Cómo Probar La Bomba de Gasolina (1990-2000 3.0L Ford Taurus) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the 3.0L OHV (Over Head Valve) V6 engine only. You can confirm this by checking the 8th digit of the VIN number. If your 3.0L is OHV, the 8th VIN character will be a letter U.

  • 3.0L V6 Ford Taurus: 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999.
  • 3.0L V6 Mercury Sable: 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999.

2000-2003 FUEL PRESSURE TESTS:

Symptoms Of A Bad Fuel Pump

The two most common fuel pump failures are a complete failure in which the fuel pump stops sending fuel to the fuel injectors or a fuel pump that is sending a volume that's lower than normal to the fuel injectors (provoking a lean air/fuel mixture).

Obviously, when the fuel pump completely fails, your 3.0L Ford Taurus isn't gonna' start. In this type of scenario, you'll see that:

  1. The engine turns over but will not start.
  2. The ignition coil pack feeding spark to all 6 cylinders.
  3. The PCM will still pulse (activate) all 6 fuel injectors.

When the fuel pump is starting to fail and under-performing, you'll probably see one or more of the following symptoms:

  1. Lean air/fuel mixture trouble codes.
  2. Rough idle.
  3. Engine starts after extended cranking.
  4. Lack of power when accelerating the vehicle down the road.
  5. Back-fires thru' the intake manifold when accelerating your pickup or van down the road.

Both of these conditions can be tested with a fuel pressure gauge. Alright, with this info under our belts, let's get testing.

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 following fuel pressure test gauge kits are pretty good deals and include the adapter to tests all 3.0L Fords:

Disclosure: As an Amazon Associate, I earn from qualifying purchases. If my tutorials help you, using these links is an easy way to support the site at no extra cost to you. Thank you!

Fuel Pressure Specifications

The fuel pressure specifications with the key on engine off (KOEO) and key on engine running (KOER) are:

YearKOEOKOER
1990-199335-40 PSI30-45 PSI
1994-199540-43 PSI35-38 PSI
1996-199835-40 PSI30-45 PSI
199937-43 PSI26-45 PSI

Fuel Pump Circuit Wiring Diagrams

TEST 1: Checking Fuel Pressure With A Fuel Pressure Gauge

In this section we'll use a fuel pressure test gauge to find out if the fuel pump is creating the factory specified pressure.

Using a fuel pressure gauge comes in handy in diagnosing either a no-start condition or lean air/fuel mixture caused by an under-performing fuel pump.

You can find the Schrader valve in these locations:

  • 1991-1995 vehicles: Located on the fuel injector rail for cylinders 1, 2, and 3 —near the point were the fuel supply line connects to it (see photo 2 of 3).
  • 1996-1999: The Schrader valve is located on the fuel injector rail for cylinders 4, 5, and 6. The Schrader valve is almost right behind the alternator (see photo 3 of 3).

NOTE: If you don't have a fuel pressure gauge, take a look at the section: Where To Buy A Fuel Pressure Test Gauge.

OK, let's get started with this test:

  1. 1

    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.

    To see the location of the Schrader valve, go here: Fuel Pump Inertia Switch: Location, Function, And Reset (1991-2007 3.0L V6 Ford Taurus, Mercury Sable).

  2. 2

    Connect the fuel pressure gauge to the Schrader valve on your 3.0L Ford Taurus's fuel injector rail.

  3. 3

    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 the connection at the Schrader valve for fuel leaks and if any tighten the fuel pressure a bit more (by hand only) to eliminate them.

  4. 4

    Your fuel pressure gauge should register the specified KOEO fuel pressure for the particular year of your 3.0L Ford in the table above if the fuel pump is OK.

Let's take a look at what your results mean:

CASE 1: Fuel pressure is 0 PSI. This confirms that the cause of your 3.0L Ford Taurus or Mercury Sable's no-start problem is caused by a lack of fuel.

The most likely cause here is a bad fuel pump. I do recommend you take one more step, though, and make sure the fuel pump is actually getting power.

This is a super easy check you can do right at the fuel pump inertia switch connector. I'll show you how to do that step by step in this tutorial: Power To Fuel Pump Check (1991-1999 3.0L V6 Ford Taurus, Mercury Sable).

CASE 2: The fuel pressure is below specification. Any fuel pressure below the spec will cause engine performance issues and points to a failing fuel pump. Replace the fuel pump.

CASE 3: Fuel pressure is within specification. This test result lets you know that the fuel pump is working and delivering enough fuel to the fuel injectors.

The reason your 3.0L Ford Taurus or Mercury Sable isn't starting is due to another reason. The fuel pump is OK.

TEST 2: Using Starting Fluid To Confirm Lack Of Fuel

Using Starting Fluid To Confirm Lack Of Fuel. How To Test The Fuel Pump (1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999 3.0L V6 Ford Taurus, Mercury Sable)

I've been using starting fluid, to diagnose a lack of fuel causing a no-start problem, since the first week on the job (some 25 years ago). It's a fast and easy test but the successful outcome of this test depends on making sure that all 6 cylinders are getting spark.

This means that you have to precede this test with a spark test on 6 spark plug wires (with a dedicated spark tester).

IMPORTANT: This is a very fast and easy test but you do have to take one very important safety precaution and this is to reconnect the air intake duct after spraying starting fluid down the throttle bore (although you don't have to fasten it). This will prevent any backfire, that might occur, from scaring the heck out of you when cranking the engine.

This is what you have to do:

  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 one of the next steps.

  2. 2

    Open the throttle plate and spray starting fluid down the bore.

    As a safety precaution reconnect the air duct after you have sprayed a good squirt of starting fluid (but you don't have to tighten the air duct's hose clamp).

  3. 3

    Crank the engine once the air duct is back on and you're clear of the engine compartment.

  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 or.

    2.) The engine will only crank but not start at all.

OK, let's find out what your results mean:

CASE 1: If the engine started and ran for a few seconds. This test result tells you that the no-start problem is due to a lack of fuel.

Your next step is to check to see what the fuel pressure is with a fuel pressure test gauge. Go to: TEST 1: Checking Fuel Pressure With A Fuel Pressure Gauge.

CASE 2: The engine did not start, not even momentarily. This usually means that a lack of fuel IS NOT the reason your car is not starting.

Now, remember what I said about this test not being very accurate? Well, I suggest you do one more test and this is to check the fuel pressure with a fuel pressure test gauge. Go to: TEST 1: Checking Fuel Pressure With A Fuel Pressure Gauge.

Fuel Pump Inertia Switch

Fuel Pump Inertia Switch. How To Test The Fuel Pump (1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999 3.0L V6 Ford Taurus, Mercury Sable)

As you're probably already aware, your Ford Taurus (Mercury Sable) comes equipped with a fuel pump inertia switch. This switch is a safety device that de-activates the fuel pump in case of an impact and once it activates, you have to manually reset it. It's usually located on the right side (passenger side) of the dash, below the glove box or in the trunk of the car.

When the inertia switch is jolted into action, the engine is not gonna' start. It'll crank but not start, which can lead you to believe that the fuel pump is bad.

Although it's designed to activate during a severe impact caused by an automobile accident, sometimes it gets activated by less than severe impacts. This means that it's always a good idea to check and reset the inertia switch whenever testing the fuel pump.

Resetting the fuel pump inertia switch simply involves pushing down on the button located on top of the inertia switch till it bottoms out.

Where To Buy The Fuel Pump And Save

The fuel pump in your 3.0L Ford Taurus is located inside the fuel tank. The fuel pump can be bought in any auto parts store, but I think you'll find the better price online. The following fuel pumps are pretty good deals:

1990-1996

1998-1999

Disclosure: As an Amazon Associate, I earn from qualifying purchases. If my tutorials help you, using these links is an easy way to support the site at no extra cost to you. Thank you!

Not sure if the above fuel pumps fit your particular 3.0L Ford Taurus? Don't worry, once you get to the site, they'll make sure it fits by asking you the specifics of your vehicle. If it doesn't fit, they'll find you the right one.

More 3.0L V6 Ford Taurus Diagnostic Tutorials

You can find a complete list of 3.0L V6 Ford Taurus and Mercury Sable diagnostic tutorials in this index:

Here's a sample of the diagnostic tutorials you'll find in the index:

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Ford Vehicles:

  • Taurus 3.0L (OHV)
    • 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000

Mercury Vehicles:

  • Sable 3.0L (OHV)
    • 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000