How To Test The Fuel Pump (1989-1993 3.1L V6 Buick Regal, Oldsmobile Cutlass Supreme)

Using Starting Fluid

I've used the starting fluid test fairly frequently over the years to diagnose engine no-start problems.

Although the test isn't as accurate as the fuel pressure test, the starting fluid test will still point your engine no-start diagnostic in the right direction.

IMPORTANT: To get the most accurate test result from the starting fluid test, you must ensure that all of the spark plug wires are sparking before beginning the test. Test all 6 spark plug wires for spark with a dedicated spark tester if you haven't already done so.

OK, 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 with this test:
   
   1.) The engine will start momentarily and after a few seconds will die or.
   
   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 isn't starting due to a lack of fuel.

I suggest that your next step be 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.

CASE 2: The engine did not start, not even momentarily. This result generally tells you 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 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.