How To Test The Fuel Pump (1992-2003 5.2L, 5.9L V8 Dodge Ram Van)

You can check if the fuel pump on your full-size Dodge Ram van is good or bad with a fuel pressure test gauge. It's a quick test, and in this tutorial, I'll walk you through the whole process step-by-step.

Once you've got your fuel pressure readings, you'll know if the fuel pump's behind either your van's no-start issue or its engine performance issue.

I'm also gonna go over how to use starting fluid to figure out if a fuel delivery problem is the reason your van's engine won't start.

APPLIES TO: This tutorial applies to the following vehicles:

• 1992-1994:
• Dodge Ram B150 Van 5.2L V8: 1992, 1993, 1994.
• Dodge Ram B250 Van 5.2L V8: 1992, 1993, 1994.
• Dodge Ram B250 Van 5.9L V8: 1992, 1993, 1994.
• Dodge Ram B350 Van 5.9L V8: 1992, 1993, 1994.
• 1995-1997:
• Dodge Ram B1500 Van 5.2L V8: 1995, 1996, 1997.
• Dodge Ram B2500 Van 5.2L V8: 1995, 1996, 1997.
• Dodge Ram B3500 Van 5.2L V8: 1995, 1996, 1997.
• Dodge Ram B2500 Van 5.9L V8: 1995, 1996, 1997.
• Dodge Ram B3500 Van 5.9L V8: 1995, 1996, 1997.
• 1998-2003:
• Dodge Ram 1500 Van 5.2L V8: 1998, 1999, 2000, 2001, 2002, 2003.
• Dodge Ram 2500 Van 5.2L V8: 1998, 1999, 2000, 2001, 2002, 2003.
• Dodge Ram 3500 Van 5.2L V8: 1998, 1999, 2000, 2001, 2002, 2003.
• Dodge Ram 1500 Van 5.9L V8: 1998, 1999, 2000, 2001, 2002, 2003.
• Dodge Ram 2500 Van 5.9L V8: 1998, 1999, 2000, 2001, 2002, 2003.
• Dodge Ram 3500 Van 5.9L V8: 1998, 1999, 2000, 2001, 2002, 2003.

1989-1991 V8 Dodge Ram Van Fuel Pressure Test:

• How To Test The Fuel Pump (1989-1991 5.2L, 5.9L V8 Dodge Ram Pickup).

FUEL PUMP WIRING DIAGRAMS:

• Fuel Pump Circuit Wiring Diagram (1992 5.2L, 5.9L V8 Dodge Ram Van).
• Fuel Pump Circuit Wiring Diagram (1993 5.2L, 5.9L V8 Dodge Ram Van).
• Fuel Pump Circuit Wiring Diagram (1994 5.2L, 5.9L V8 Dodge Ram Van).
• Fuel Pump Circuit Wiring Diagram (1995 5.2L, 5.9L V8 Dodge Ram Van).
• Fuel Pump Circuit Wiring Diagram (1996 5.2L, 5.9L V8 Dodge Ram Van).
• Fuel Pump Circuit Wiring Diagram (1997 5.2L, 5.9L V8 Dodge Ram Van).
• Fuel Pump Circuit Wiring Diagram (1998-1999 5.2L, 5.9L V8 Dodge Ram Van).
• Fuel Pump Circuit Wiring Diagram (2000-2003 5.2L, 5.9L V8 Dodge Ram Van).

Symptoms Of A Bad Fuel Pump

It's been my experience over the years having diagnosed a ton of fuel pumps that most of the time, a fuel pump fails in one of two ways:

• Total failure: The pump just quits, and the engine won't start at all.
• Weak output: The pump still runs, but it doesn't push enough fuel to the injectors. Although the engine still starts, it runs like very bad.

If the fuel pump is weak but still manages to start the engine, you'll run into one or more of these problems:

• Rough idle: The engine runs rough at idle.
• Hard start: Seems like you've to crank the engine forever before it finally starts.
• Low power: You press the gas, but the engine feels sluggish or unresponsive.
• Backfires: It backfires through the intake when you try to accelerate (either from a standstill or at cruising speed).
• Running lean: You'll get lean mixture codes like P0171, P0174, or both (OBD-II equipped vans).

Doesn't matter if your van won't start or just runs like trash — a simple fuel pressure test will tell you if the fuel pump's the one to blame.

Fuel Pressure Specifications

1992
5.2L	39 PSI (Key On Engine Off -KOEO and vacuum hose disconnected from fuel pressure regulator)
5.9L	14.5 PSI (Throttle Body Injection -TBI- System)

1993
5.2L	31 PSI (Key On Engine Running with vacuum hose connected to fuel pressure regulator) NOTE: 8 to 10 PSI higher with vacuum hose disconnected to fuel pressure regulator.
5.9L	35-45 PSI (Key On Engine Running At Idle -No Load and vacuum hose connected to fuel pressure regulator)

1994-1995
5.2L	35-45 PSI (Key On Engine Running At Idle -No Load)
5.9L	35-45 PSI (Key On Engine Running At Idle -No Load)

1996-1997
5.2L	44-54 PSI (Key On Engine Off)
5.9L	44-54 PSI (Key On Engine Off)

1998-2000
5.2L	44-54 PSI (Key On Engine Running At Idle -No Load)
5.9L	44-54 PSI (Key On Engine Running At Idle -No Load)

2001-2003
5.2L	44-54 PSI (Key On Engine Off)
5.9L	44-54 PSI (Key On Engine Off)

NOTE: If your Dodge Ram van does not start and there's only a key on engine running (KOER) fuel pressure specification, then that KOER specification will apply to your key on engine off (KOEO) fuel pressure test.

Where To Buy A Fuel Pressure Test Gauge

The fuel pressure gauge test kits below can all connect to the Schrader valve on the fuel injector rail.

NOTE: Before buying any of these, make sure your van's fuel rail actually has a Schrader valve. Some don't —and in that case, you'll need a totally different type of fuel pressure test kit. If your van falls into that group, check this section: Fuel Pressure Test Gauge For Non-Schrader Valve Fuel Injector Rail.

Fuel Pressure Test Gauge For Non-Schrader Valve Fuel Injector Rail

No Schrader valve on your Dodge Ram Van's fuel rail? This fuel pressure test gauge comes with the adapter you need:

TEST 1: Checking Fuel Pressure With A Fuel Pressure Gauge

I know I'm starting to sound like a broken record, but it's worth repeating —some Dodge Ram vans don't come with a Schrader valve on the fuel injector rail.

If that's your setup, don't worry —you can still connect a fuel pressure gauge. You'll just need a special adapter. Check out image 3 of 3 in the image viewer above to see what it looks like.

FUEL RAIL WITH SCHRADER VALVE: If you don't own a fuel pressure gauge and need to buy on, see my recommendations here: Where To Buy A Fuel Pressure Test Gauge.

FUEL RAIL WITHOUT SCHRADER VALVE: The gauge kit you need comes with that adapter, and it won't break the bank. You can see it here: Fuel Pressure Test Gauge For Non-Schrader Valve Fuel Injector Rail.

IMPORTANT: Some Dodge Ram vans (1996 to 2003), a scan tool is required to activate the fuel pump to read its fuel pressure. If you don't one, no worries. The instructions below take into account having one and not having one.

Alright, let's run the test:

1. 1

   Wrap a shop towel around the Schrader valve. That towel's gonna soak up any fuel that might leak during the next step.

2. 2

   Connect your fuel pressure gauge to the Schrader valve (see image 1 of 3 and image 2 of 3).
   
   No Schrader valve? Do this instead:
   
   A) Relieve the fuel system pressure (see: Fuel Pressure Release Procedure).
   
   B) Disconnect the fuel line from the injector rail.
   
   C) Install the adapter between the injector rail and the fuel line (see image 3 of 3).

3. 3

   Have your helper turn the key ON and OFF without cranking the engine while you keep an eye on the fuel pressure gauge adapter connection points for any signs of leaking.
   
   NOTE: If you spot fuel leaking where the gauge connects to the rail, fix it before moving on to the next step..

Key On Engine Running (KOER) Only:

1. 4

   Fire up the engine.

2. 5

   The fuel pressure gauge should now show the correct PSI for your van's model and year.
   
   You can check the chart here: Fuel Pressure Specifications.

Key On Engine Off (KOEO) Without a Scan Tool:

1. 4

   Disconnect the ignition coil's 2-wire plug.
   
   NOTE: This method only works if your van has a KOEO fuel pressure specification.

2. 5

   Crank the engine briefly, then let go of the key.

3. 6

   The gauge should show the correct pressure value for your specific year and model.
   
   See the numbers here: Fuel Pressure Specifications.

Key On Engine Off (KOEO) Using a Scan Tool:

1. 4

   Hook up your scan tool to the diagnostic link connector (DLC).

2. 5

   Use the scan tool to activate the fuel pump.

3. 6

   The gauge should now read the proper fuel pressure for your van's year and model.
   
   Reference it here: Fuel Pressure Specifications.

Now let's break down what your results mean:

CASE 1: The fuel pressure gauge reads 0 PSI. That tells you the no-start issue is because the fuel pump isn't delivering fuel to the injectors.

This result, in about 90% of the cases, points to a bad fuel pump. Before you call the pump bad, double-check that it's getting power while the engine's cranking. This rules out the fuel pump relay and related fuses.

To do that, grab a multimeter, set it to DC Volts, and tap into the wire that powers the pump. While a helper cranks the engine, watch for 12 Volts at the pump wire. If power's there, then yeah — the fuel pump's done and needs replacing.

CASE 2: The fuel pressure is below spec. That means the pump's weak. It's not completely dead, but it's not doing its job either. Replace the fuel pump with a new one.

CASE 3: The fuel pressure is right where it should be. That's the result you want.

This means the fuel pump is working and sending the right amount of fuel to the injectors. If your van's still not starting, the problem lies somewhere else —but you can cross the fuel pump off your list.

TEST 2: Using Starting Fluid To Confirm Lack Of Fuel

One quick and dirty way to figure out if a no-start issue is being caused by a lack of fuel is the starting fluid test.

The test's simple and it's always been my go-to test when diagnosing an engine no-start problem. It involves spraying some starting fluid into the throttle body, cranking the engine, and seeing what happens.

If a fuel delivery problem is behind the no-start, the engine will fire up for a few seconds and then die as soon as the starting fluid burns off.

Now, this isn't the most precise way to diagnose a bad fuel pump, but it's a solid first step that can point you in the right direction.

NOTE: To get an accurate/reliable test result, you've gotta make sure all 8 spark plug wires are firing spark. If you haven't checked for spark yet, do that now.

IMPORTANT: This test's fast and easy — but don't skip this one safety step: after spraying the starting fluid into the throttle body, put the lid back on the air filter assembly before you crank the engine (no need to tighten it). This helps prevent any backfire (and maybe flames) from jumping out and scaring the life outta you.

Here's how to run the test:

1. 1

   Remove the lid from the air filter cleaner assembly.
   
   NOTE: No need to pull the entire air filter cleaner assembly completely off —just the lid.

2. 2

   Hold the throttle plate open and spray a solid squirt of starting fluid down the bore.
   
   After spraying, go ahead and place the air cleaner lid back on. You don't have to tighten it.

3. 3

   Crank the engine once the lid's back on and your hands are out of the engine bay.

4. 4

   One of two things is gonna happen:
   
   1.) The engine starts and runs for a few seconds, then shuts off.
   
   2.) The engine cranks but doesn't start at all.

Now let's go over what your result means:

CASE 1: The engine fired up and ran briefly. That confirms your van isn't starting because it's not getting fuel.

This could point to a bad fuel pump. Next step: check actual fuel pressure with a gauge. Go to: TEST 1: Checking Fuel Pressure With A Fuel Pressure Gauge.

CASE 2: The engine cranked but didn't start at all. That usually tells you a fuel delivery problem isn't the issue behind the engine's no-start.

Like I said earlier —this test isn't the most accurate thing in the world (to diagnose a bad fuel pump). So even if it didn't start, I still recommend doing a proper fuel pressure test. Go to: TEST 1: Checking Fuel Pressure With A Fuel Pressure Gauge.

Fuel Pressure Release Procedure

Before hooking up the fuel pressure test adapter to your van's fuel rail (that doesn't have a Schrader valve), you've gotta release the pressure in the fuel line first.

Here's how to do it on your full-size Dodge Ram van:

1. Pull the fuel pump relay out of the Power Distribution Center —that's the fuse and relay box under the hood.
2. Crank the engine. If it starts, let it run until it stalls out on its own.
3. Keep cranking the engine a few more times, or until it refuses to start anymore.
4. Wrap a shop towel around the fuel line and disconnect it from the fuel rail.
   • The towel catches whatever fuel is still left in the line.
5. Put the fuel pump relay back in place.
6. After you're done testing fuel pressure, clear out any diagnostic trouble codes that might've popped up from cranking the engine without the relay installed.

More 5.2L, 5.9L V8 Dodge Ram Van Diagnostic Tutorials

I've written quite a few ‘how to’ tutorials for the full-size Dodge Ram van with a V8 engine. You can find them in this index:

• 5.2L, 5.9L V8 Dodge Ram Van Index Of Articles.

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

• How To Test The MAP Sensor (1998-2003 5.2L, 5.9L V8 Dodge Ram Van).
• How To Test The Intake Air Temp (IAT) Sensor (1998-2003 5.2L, 5.9L V8 Dodge Ram Van).
• How To Test Engine Compression (1989-2003 5.2L, 5.9L V8 Dodge Ram Van).
• How To Test For A Blown Head Gasket (1989-2003 5.2L, 5.9L V8 Dodge Ram Van).