How To Test The Fuel Pump (2002-2005 GM 2.2L Ecotec)

When the fuel pump fails, your car is not gonna' start. Thankfully, testing the fuel pump on your 2.2L Ecotec equipped GM vehicle is not that hard.

So if you suspect that your car is not starting due to a bad fuel pump, this is the tutorial that'll help you find out (without having to replace the fuel pump first). I'll explain how to do the fuel pump test in a step-by-step way, and what tools you'll need (and where to get them).

IMPORTANT: Gasoline is extremely flammable. Be careful and take all necessary safety precautions. Use extreme care when using starting fluid since it ignites as easily as gasoline. Accomplishing both tests indicated in this article, without any unhappy consequences, is more than possible if you're careful and use common sense.

You can find this tutorial in Spanish here: Cómo Probar La Bomba De Combustible (2002-2005 2.2L Alero, Cavalier, Grand Am, Sunfire) (at: autotecnico-online.com).

Symptoms Of A Bad Fuel Pump

As you're probably already aware, each of your 2.2L Ecotec's 4 cylinders needs fuel, spark, and air to produce power. When any of these are missing from the mix, your car is going to crank but not start. In other words when you turn the key to start the engine, the engine only turns over but doesn't start.

Here are some more specific symptoms:

1. All of the coil packs, sitting on top of the ignition control module, are creating and delivering spark to the spark plugs. So you know that the ignition system is not at fault.
2. You've sprayed starting fluid (or carburetor spray) into the throttle body and your vehicle started, even if only momentarily.

Although the above list is a not a very complete list of symptoms the theme that runs thru' them and any other related symptom, is that the engine will crank and crank, but not start.

TEST 1: Using Starting Fluid

Using starting fluid, to confirm a lack of fuel condition causing a no-start problem, is a very old troubleshooting technique. But, it's not the most accurate way to troubleshoot a failed fuel pump.

Unfortunately the factory anti-theft system (PASS-Key/Passlock) on your car can mimic a failed fuel pump. The starting fluid test won't be able to tell you whether the lack of fuel problem is caused by an anti-theft system problem or a bad fuel pump. This means that you still have to do a fuel pressure test (to check the fuel pump).

The starting fluid test still has its merits. Because it is a good way verify if the no-start problem is due to a lack of fuel condition (either due to a bad fuel pump or an anti-theft problem).

OK, to get this show on the road, 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

   Once the intake air duct is back on the throttle body, have your assistant, inside the vehicle, crank the engine.

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 find out what your results mean:

CASE 1: If the engine started and ran for a few seconds. This means that the reason your car is not starting is due to a lack of fuel. This will usually be due to one of two things: a bad fuel pump or a problem with your car's anti-theft system (PASS-key/Passlock).

I suggest that your next step be to test the fuel pump's fuel pressure with a test gauge. For this test go to: TEST 2: Testing Fuel Pressure With A Fuel Pressure Test Gauge.

For more info about an anti-theft system failure go to: Is The Anti-Theft System Causing The No-Start Condition?

CASE 2: The engine did not start, not even momentarily. This usually means that 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: TEST 2: Testing Fuel Pressure With A Fuel Pressure Test Gauge.