Testing the fuel pump isn't difficult at all on the 2.4L engine in your minivan. In this tutorial, I'll explain how using a fuel pressure test gauge.
With your test results you'll easily find out if the fuel pump is bad or not.
I'll also show you how to use starting fluid to figure out if your mini-van's engine no-start problem is due to a lack of fuel.
Contents of this tutorial:
You can find this tutorial in Spanish here: Como Probar La Bomba De Combustible (1996-2000 2.4L Caravan, Grand Caravan, Voyager, Grand Voyager) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 2.4L Chrysler Voyager: 2000.
- 2.4L Dodge Caravan: 1996, 1997, 1998, 1999, 2000.
- 2.4L Dodge Grand Caravan: 1996, 1997.
- 2.4L Plymouth Voyager: 1996, 1997, 1998, 1999, 2000.
- 2.4L Plymouth Grand Voyager: 1996, 1997.
CAUTION: Gasoline and starting fluid are extremely flammable. Be careful and take all necessary safety precautions. Make sure to perform all tests with a cooled down engine, work in a well-ventilated area, and stay away from open flames or sparks.
Symptoms Of A Bad Fuel Pump
The fuel pump in your minivan is going to fail in one of two ways. Here are the specifics:
- Complete failure: This is the most common type of failure and will cause the engine to not start.
- Slow failure: In this type of failure, the engine starts and runs but runs bad, especially under load.
To be a bit more specific, here are some of the symptoms you'll see from a complete fuel pump failure:
- The engine cranks but doesn't start.
- No fuel pressure is detected.
- No noise from the fuel pump.
These are some of the symptoms of a slow fuel pump failure:
- Lack of power when accelerating the engine under load.
- Unexplained loss of power.
- Bad gas mileage.
- The engine suddenly stalls.
Whether the fuel pump in your mini-van has suffered a complete failure or is just starting to fail, a fuel pump pressure test will help you identify the problem. Not only that, but this simple test will speed up your fuel pump diagnostic, meaning you'll spend less time (and less frustration) solving the issue and be able to replace the right part.
Where to Buy a Fuel Pressure Gauge
You'll need a fuel pressure test gauge kit to check the fuel pump pressure. The good news is that you can buy them at almost any auto parts store and online (and they don't cost an arm a leg).
The following fuel pressure test kits are very good deals and will connect to the vehicles included in this tutorial:
All of the fuel pressure test kits above have the adapter that'll connect to the fuel pressure test port of your mini-van.
Fuel Pressure Specifications
|2.4L Caravan, Grand Caravan, Voyager, Grand Voyager|
|1996-2000||47-51 PSI||Not Given|
- KOEO = Key On Engine Off.
- KOER = Key On Engine Running.
Fuel Pressure Test With A Gauge
The thing that makes testing the fuel pump easy on your 2.4L equipped minivan is that the fuel injector rail comes equipped with a test port. This test port is known as a Schrader valve (see photo above).
It's to this Schrader valve that we're gonna connect a fuel pressure test gauge and check the fuel pump's pressure.
If the fuel pump is functioning correctly, you should obtain a fuel pressure reading that matches the specifications listed here: Fuel Pressure Specifications.
OK, let's get started:
Disconnect the ignition coil from its electrical connector.
NOTE: This step only applies if the engine starts and runs.
Remove the dust cap from the Schrader valve on the fuel injector rail.
Place a towel under the area of the Schrader valve.
Connect the fuel pressure gauge to the Schrader valve.
Use a towel to dry any fuel that may have been released during the gauge connection process.
When you're ready, have your assistant crank the engine while you observe the pressure gauge.
The gauge should display the specified fuel pressure.
Let's analyze your test result:
CASE 1: The fuel pump pressure is within specification. This tells you the fuel pump is in good working condition and supplying fuel to the injectors.
If the engine doesn't start, then this test result rules out the fuel pump as the source of the engine's 'cranks but does not start' issue.
CASE 2: The fuel pump pressure is NOT within specification. This result tells you that the fuel pump is not functioning. Since the fuel pump isn't working, you can now conclude that it's behind the 'cranks but does not start'.
Using Starting Fluid To Check For A Lack Of Fuel
The starting fluid test has been one of my go-to methods for testing an engine no-start problem since the early days of my auto repair career.
This test consists of spraying starting fluid into the throttle body and then having a helper crank the engine. If the engine starts and runs for a few seconds, you can bet it's not getting fuel from the pump. If it doesn't start (with the starting fluid), then there's another issue at play.
IMPORTANT: This test is accurate only when all four spark plug wires are delivering spark to their spark plugs, so test them for spark with a spark tester before you begin.
OK, here are the test steps:
Remove the intake air 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.
Manually open the throttle plate and spray starting fluid into the throttle body bore.
Quickly reconnect the air duct to the throttle body (no need to tighten the hose clamp).
NOTE: Reconnecting the intake air duct is a very important safety precaution in case of backfire through the intake manifold.
Crank the engine once the intake air duct is back on the throttle body.
You'll get one of two results:
1.) The engine will briefly start, run and then shut off after a few seconds.
2.) The engine cranks but doesn't start at all.
Alright, let's figure out what it all means:
CASE 1: The engine started and ran for a few seconds. This confirms that the issue of your vehicle cranking but not starting is due to a lack of fuel.
I suggest your next step should be testing the fuel pump pressure with a pressure gauge. For this test, go to: Fuel Pressure Test With A Gauge.
CASE 2: The engine did NOT start, not even briefly. This indicates that a lack of fuel is not the reason why the engine won't start.
If this info saved the day, buy me a beer!