How To Test The Fuel Pump (Chrysler 2.0L, 2.4L)

FUEL PUMP TEST 2: Using Starting Fluid

Using starting fluid (or carburetor cleaner spray) to check to see if the no-start condition is due to a lack of fuel is one of the ‘oldest tricks in the book’ that techs use and in this first test, I'll explain how to do it.

Let me tell you, this method is not the most accurate way of testing the fuel pump but it doesn't mean it's not effective. Before you start this test, I recommend you make sure that all four cylinders are getting spark (using a spark tester).

Making sure all cylinders are getting spark will ensure the accuracy of this starting fluid test.

OK, to get this show on the road, this is what you'll need 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, manually, and spray starting fluid down the bore.

3. 3

   When you have sprayed a good squirt of starting fluid, quickly reconnect the air duct to the throttle body (you don't have to tighten the hose clamp).
   
   IMPORTANT: Reconnecting the intake air duct is a very important safety precaution in case you get a back-fire thru' the intake manifold.

4. 4

   Have your assistant crank the engine once the intake air duct is back on the throttle body.

5. 5

   You'll get one of two results with this test:
   
   1.) The engine will start momentarily and after a few seconds will die.
   
   2.) The engine will only crank but not start at all.

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

CASE 1: The engine started and ran for a few seconds. This means that the root cause of the no-start your Chrysler vehicle is currently experiencing is due to a lack of fuel.

Usually, this also means that the fuel pump is bad. But since we don't live in a perfect world, this could also mean a few other things like: the fuel pump fuse is blown, or the fuel pump relay is bad.

Your next step is buy or rent a fuel pressure gauge and actually check fuel pressure (your local auto parts store, like AutoZone or O'Reilly Auto Parts will rent the fuel pressure gauge to you for free for a cash deposit which they'll return to you when you return the tool).

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.

The next test is to actually verify the fuel pressure with a fuel pressure gauge. You can buy one or rent one (your local auto parts store, like AutoZone or O'Reilly Auto Parts will rent the fuel pressure gauge to you for free for a cash deposit which they'll return to you when you return the tool).

Related Test Articles

If you enjoyed and/or found this ‘How to’ article helpful, I have written several more 4.0L specific test articles. You can find here: Chrysler 2.0L, 2.4L Index Of Articles.

The following tutorials are a sample of the articles you'll find in the index:

• How To Test The Engine Compression (Chrysler 2.0L, 2.4L).
• How To Test A Fuel Injector (Chrysler 2.0L, 2.4L).
• How To Test The Coil Pack (Chrysler 2.0L, 2.4L) (at: easyautodiagnostics.com).
• How To Test The Crank Sensor (Chrysler 2.0L, 2.4L).
• How To Troubleshoot A No Start (Chrysler 2.0L, 2.4L).