How To Test The Fuel Pump (3.1L V6 Buick, Oldsmobile)

Using Starting Fluid

The starting fluid test is a pretty simple way of checking to see if the engine is not starting due to a lack of fuel (like when the fuel pump stops working).

This test is usually the first test I perform when diagnosing a no-start problem.

Although the starting fluid test is not the most accurate way of diagnosing a bad fuel pump, it will get your no-start diagnostic pointing in the right direction.

IMPORTANT: To get the most accurate test result from this test you need to first make sure that all 6 spark plug wires are sparking. If you haven't already, test all 6 spark plug wires for spark with a dedicated spark tester.

OK, 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.
   
   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 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: If the engine started and ran for a few seconds. This test result lets you know that the engine's no-start problem is due to lack of fuel.

Now remember, this isn't the most accurate way of diagnosing a bad fuel pump. If I were in your shoes I would test the fuel pump's 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 momentarily. This test result most always tells you that the engine's no-start problem IS NOT due to a lack of fuel from the fuel pump.

Now, remember what I said about this test not being very accurate? Well, I suggest you do one more test and this is to test the fuel pump's fuel pressure with a test gauge. For this test go to: Using A Fuel Pump Pressure Tester To Test The Fuel Pump.

More 3.1L V6 Buick, Oldsmobile Tutorials

You can find a complete list of 3.1L V6 Buick (Oldsmobile) tutorials in this index:

• GM 3.1L Index Of Articles.

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

• How To Test Engine Compression Test (3.1L V6 Buick, Oldsmobile).
• How To Test A Blown Head Gasket (3.1L V6 Buick, Oldsmobile).
• How To Test The 24X Crankshaft Position Sensor (1995-1997 3.1L V6 Oldsmobile Cutlass Supreme).
• What Does The CKP Sensor Do? (3.1L V6 Buick, Oldsmobile).