Troubleshooting the fuel pump, to see if it has failed and thus the cause of your vehicle's no-start condition, is not that hard.
What makes it easy, is that Chrysler has provided a fitting on the fuel injector rail (called a Schrader valve) to which you can connect a fuel pressure gauge to and test the fuel pump.
In this tutorial, I'll show how to do it and where to get the fuel pressure gauge you'll need to get the test done.
Contents of this tutorial:
IMPORTANT: Gasoline is extremely flammable! Take all necessary safety precautions, be alert, be careful. Starting fluid and gasoline can ignite very easily.
Symptoms Of A Bad Fuel Pump
A bad fuel pump will generally cause one of two problems:
- An engine no-start problem.
- The engine starts and runs, but runs badly under load.
If the engine starts and runs, but the fuel pump is failing, you'll see one or more of the following:
- The engine takes a long time to start (extended cranking time).
- The engine backfires thru' the intake manifold under load.
- The engine idles rough when placing the automatic transmission in Drive.
- Lack of power when you accelerate the vehicle on the road.
Where To Buy A Fuel Pressure Gauge
Owning a fuel pressure gauge is now becoming a must. All vehicles now use an electrical fuel pump to deliver fuel (under high pressure) to the fuel injectors and the best way to diagnose this fuel pump is with a fuel pressure gauge.
Thankfully, a Schrader valve is located on the fuel injector rail where you can tap into the fuel system and check its performance.
A fuel pressure gauge can cost you as little as $40 (US) or as much as $200 (US). The price difference depends on what type of fuel pressure gauge set you buy, this means either buying a non-professional technician grade tool or a professional technician grade too. Whichever one you buy, it's an investment that will pay for itself many times over.
Your local parts house will have a fuel pressure gauge set to sell you, although you'll pay more for it and it won't be a professional grade tool (if that's what you're looking for).
FUEL PUMP TEST 1: Fuel Pressure Test With Gauge
Depending on the specific Chrysler vehicle you own/drive, the Schrader valve will be in plain sight, on the fuel injector rail, or on the fuel line that feeds fuel to the fuel injector rail (see photos in the image viewer).
Using a fuel pressure gauge is the best way to test the fuel pump. If you don't own one, see my recommendations here: Which And Where To Buy A Fuel Pressure Gauge.
OK, let's get started with this test:
- 1
Place a shop towel under the Schrader valve. The shop towel's job is to absorb any fuel that may leak when doing step 2.
- 2
Connect the fuel pressure gauge to the Schrader valve adapter.
- 3
When ready, ask your helper to cycle the key ON and OFF but don't crank the engine while checking for fuel leaks.
If no fuel leaks, go to next step.
If fuel is leaking, resolve the leak before continuing to the next step . - 4
Have your helper to crank the engine while you observe the fuel pressure tester's gauge.
- 5
Your fuel pressure gauge will register one of the two following results:
1.) The fuel pressure gauge will register the indicated fuel pressure specification
2.) The fuel pressure gauge will NOT register the indicated fuel pressure specification.
OK, now that the testing part is done, let's take a look at what your results mean:
CASE 1: The fuel pressure gauge registered 0 PSI. This confirms that the cause of your 2.0L, 2.4L Chrysler car or mini-van is caused by a lack of fuel.
Now, I usually take one more precaution, before condemning the fuel pump as bad and this is to check that the fuel pump is getting 12 Volts as the engine is cranking. This is just to make sure that the fuel pump relay and fuse are OK and doing their job.
What you'll have to do to accomplish this is to attach a multimeter in Volts DC mode to the wire that supplies this voltage to the fuel pump and while a helper cranks the engine, verify that the fuel pump is getting this power. If the 12 Volts are being supplied to the fuel pump, you have now 100% verified that the fuel pump is fried and needs to be replaced.
CASE 2: The fuel pressure gauge registered 35 PSI. This fuel pressure gauge result lets you know that the fuel pump is working and delivering enough fuel to the fuel injectors. The reason your 2.0L, 2.4L Chrysler vehicle is not starting is due to another reason. The fuel pump is OK.
I suggest you take a look at the section Related Test Articles to see more testing options.
