How To Test The Fuel Pump (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon)

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

A quick way to find out if the engine's no-start problem is being caused by a lack of fuel is a starting fluid test.

This test involves spraying starting fluid into the throttle body and cranking the engine to see if it starts.

If the engine starts and runs (although just for a few seconds), then you can conclude that the engine's no-start problem is due to a lack of fuel.

The starting fluid test is not a very precise way of checking the fuel pump, but it does help in pinpointing the engine's no-start problem to a lack of fuel (if the fuel pump isn't working).

IMPORTANT: For the starting fluid test to give you an accurate test result you first have to make sure 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 Silverado (Suburban, Tahoe) And GMC Sierra (Yukon, Yukon XL) Tutorials

You can find a complete list of V8 Chevrolet Silverado (Suburban, Tahoe) and GMC Sierra (Yukon, Yukon XL) tutorials in this index:

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

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

• Resistance Specifications Of The TAC Electronic Throttle Body.
• How To Test The GM Accelerator Pedal Position (APP) Sensor 2.
• How To Test The MAF Sensor (GM 4.8L, 5.3L, 6.0L, 8.1L).
• Blown Head Gasket Test (GM 4.8L, 5.3L, 6.0L).