How To Test The Fuel Pump (2000-2005 2.0L SOHC Dodge/Plymouth Neon)

Fuel Pressure Test With A Gauge (Without Schrader Valve)

If your Neon doesn't have a Schrader valve on the injector rail, you can still check the fuel pump pressure. You just need a different adapter for the gauge.

In these vehicles, you'll connect the gauge where the fuel supply line enters the injector rail. In the photo above, the orange arrow shows you where.

According to the factory repair manual, the way you need to check the fuel pump pressure is by using an expensive professional grade scan tool to activate it with the key on and the engine off.

But there's another way: if the engine starts, simply disconnect the electrical connectors from the fuel injectors and crank the engine. The steps below assume that you're not using a scanner to activate the fuel pump and check the pressure.

OK, here are the steps for the test:

1. 1

   Disconnect the four fuel injectors from their electrical connectors.
   
   NOTE: This step only applies if the engine cranks and starts.

2. 2

   Disconnect the fuel inlet line from the injector rail.
   
   NOTE: As a safety measure, place a towel in the area under the fuel line to catch/absorb any spilled fuel.

3. 3

   Connect the gauge adapter to the injector rail.

4. 4

   Connect the fuel supply line you just disconnected to the adapter.

5. 5

   Connect the gauge to the adapter.

6. 6

   When you're ready, ask your assistant to crank the engine while you observe the gauge.

7. 7

   The gauge should report the specified fuel pressure.

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

CASE 1: The fuel pump pressure is within specification. This tells you that the fuel pump is in good working condition and is supplying fuel to the injectors.

If your Neon's engine does not start, then the result of this test now rules out the fuel pump as the source of the 'cranks but does not start' issue with the engine.

CASE 2: The fuel pump pressure is NOT within specification. This result tells you that the fuel pump is not working. Since the fuel pump isn't working, you can now conclude that it's behind the 'cranks but does not start' issue with your Neon.

Using Starting Fluid To Test For A Lack Of Fuel

Performing a starting fluid test is a simple and quick process that'll help you determine if the engine won't start due to a lack of fuel. However, it's important to note that this test is not as accurate as actually measuring the fuel pump's pressure output with a gauge.

Another crucial point you should consider is that, before starting and in order to get an accurate result from this test, you need to make sure all four cylinders are receiving spark.

You can easily find this out by using a spark tester and testing the spark on each spark plug wire. Once you've verified that all cylinders have spark, you'll be ready for the starting fluid test.

OK, here are the steps for the test:

1. 1

   Remove the air intake duct from the throttle body.
   
   You don't have to remove it completely, as you'll need to reconnect it in one of the following steps.

2. 2

   Manually open the throttle plate and spray starting fluid into the throttle body bore.

3. 3

   Quickly reconnect the air intake duct to the throttle body (you don't need to tighten the hose clamp).
   
   NOTE: Reconnecting the air intake duct is a very important safety precaution in case of a backfire through the intake manifold.

4. 4

   Crank the engine once the air intake duct is back on the throttle body.

5. 5

   You'll get one of two results:
   
   1.) The engine will momentarily start, run, and then shut off after a few seconds.
   
   2.) The engine will only crank but won't start at all.

Alright, let's find out what your test results mean:

CASE 1: The engine started and ran for a few seconds. This confirms that your vehicle's 'cranks but does not start' problem is due to a lack of fuel.

I suggest that your next step should be to test the fuel pump's pressure with a gauge. For this test, go to:

• Fuel Pressure Test With A Gauge (With Schrader Valve).
• Fuel Pressure Test With A Gauge (Without Schrader Valve).

CASE 2: The engine DID NOT start, not even momentarily. This tells you that a lack of fuel is not behind the engine not starting.