How To Test The Fuel Pump (1995-1997 2.3L Ford Ranger)

Using Starting Fluid

One of the tests I often run when diagnosing an engine no-start problem is the starting fluid test.

The starting fluid test consists of spraying a good amount of starting fluid into the throttle body bore and then having an assistant crank the engine.

If the engine starts, I can correctly conclude that the engine no-start problem is due to lack of fuel (usually from a bad fuel pump).

If the starting fluid does not get the engine to start, I can continue troubleshooting the engine no-start problem with other tests.

If a lack of fuel is causing the engine not to start, the starting fluid will cause the engine to start and run for a few seconds.

I want you to know that even after confirming that the engine starts and run for a few seconds (with starting fluid), I still do a fuel pressure test to make sure the fuel pump is defective.

IMPORTANT: The accuracy of the starting fluid test depends on all four spark plugs delivering sparks to their cylinders. If you have not checked the spark plug wires for spark (using a spark tester), do so before beginning the test. Otherwise, you may get a false positive result with this test.

These are the test steps:

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.
   
   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).
   
   Reconnecting the intake air duct is a very important safety precaution in case you get a back-fire thru' the intake manifold.

3. 3

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

4. 4

   You'll get one of two results:
   
   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 analyze your test result:

CASE 1: The engine started and ran for a few seconds. This result confirms that the engine's no-start problem is caused by a lack of fuel.

I suggest your next step is to test the fuel pump fuel pressure with a test gauge. For this test go to: Using A Fuel Pump Pressure Tester To Test the Fuel Pump.

CASE 2: The engine DID NOT start, not even briefly. This result generally tells you that a lack of fuel is NOT the reason the engine won't start.

Remember what I said about this test not being very accurate? Well, I suggest you do one more test and test the fuel pressure with a fuel pressure tester. For this test go to: Using A Fuel Pump Pressure Tester To Test the Fuel Pump.

More 2.3L Ford Ranger Tutorials

A full list of 2.3L Ford Ranger and Mazda B2300 tutorials can be found here:

• Ford 2.3L Index Of Articles.

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

• How To Test The Throttle Position Sensor (2.3L Ranger, Mustang, B2300).
• How To Test The Ignition Module And Crank Sensor (2.3L Ranger, Mustang, B2300).
• How To Test For A Blown Head Gasket (2.3L Ranger, Mustang, B2300).
• Testing The Blower Resistor (1995-1997 2.3L Ford Ranger).