How To Test The Fuel Pump (2003-2007 V8 Chevrolet Express, GMC Savana)

TEST 2: Using Starting Fluid To Diagnose A No-Start Condition

The starting fluid test it is a test that I've used quite a bit over the years to find out if the engine's no-start problem is due to a lack of fuel.

The starting fluid test simply involves spraying starting fluid into the throttle body and then having a helper prank the engine.

If the engine's no-start problem is being caused by a lack of fuel, then the engine will start for a few seconds and then die (as the starting fluid is consumed).

If the engine does not start, then you can conclude that the no-start problem is not due to a lack of fuel.

One very important thing to keep in mind, is that the starting fluid test is not a very accurate way to diagnose a bad fuel pump (compared to a fuel pump pressure test).

Even so, the starting fluid test does help in pinpointing the engine's no-start problem to lack of fuel (if that's the cause).

IMPORTANT: To get the most accurate test result from your starting fluid test, it's important that you first check that all 8 cylinders are getting spark. So if you haven't already checked for spark yet, you should do so before doing the starting fluid 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 step 2.

2. 2

   Spray starting fluid down the bore of the throttle body.
   
   After spraying a good squirt of starting fluid, quickly reconnect the air duct to the throttle body (you don't have to tighten the hose clamp)

3. 3

   Have your helper 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: The engine did not start, not even a few seconds. This test result tells you that a lack of fuel from the fuel pump IS NOT causing the engine's no-start problem.

I want to point out that this conclusion is true only if all spark plug wires are sparking.

CASE 2: The engine started but died after a few seconds. This test result tells you that the engine's no-start problem is caused by a lack of fuel.

I want to point out that this conclusion is true only if all spark plug wires are sparking.

More Chevrolet Express (GMC Savana) Tutorials

You can find a complete list of V8 Chevrolet Express (GMC Savana) tutorials in this index:

1. GM 4.8L, 5.3L, 6.0L Index Of Articles.

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

1. Crank Sensor Test -No Spark No Start Tests (GM 4.8L, 5.3L, 6.0L).
2. Bad Fan Clutch Troubleshooting Case Study (GM 4.8L, 5.3L, 6.0L).
3. How To Do A Compression Test (2003-2014 V8 Chevrolet Express, GMC Savana).
4. Ignition Coil Circuit Wiring Diagram (2003-2007 V8 Chevrolet Express, GMC Savana).

If this info saved the day, buy me a beer!