In this tutorial, I'm going to explain how to test the EGR valve. You don't need expensive diagnostic equipment, not even a scan tool!
You'll find step-by-step instructions that'll help you easily and quickly find out if the EGR valve is good or bad.
Contents of this tutorial:
- Symptoms Of A Bad EGR Valve.
- Important Testing Tips.
- What Tools Do I Need To Test The EGR Valve?
- TEST 1: Checking For Continuous Vacuum To EGR Valve.
- TEST 2: Applying Vacuum To The EGR Valve.
- TEST 3: Bench Testing The EGR Valve.
- TEST 4: Making Sure The EGR Valve Pintle Is Not Stuck Open.
- TEST 5: Checking For Blocked EGR Passages.
- How Can I Tell If I Have A Negative Or Positive Back Pressure EGR Valve?
- More 2.2L Buick Century And Oldsmobile Cutlass Ciera Test Tutorials.
You can find this tutorial in Spanish here: Cómo Probar La Válvula EGR (1993-1995 2.2L Buick Century, Oldsmobile Cutlass Ciera) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 2.2L Buick Century: 1993, 1994, 1995.
- 2.2L Oldsmobile Cutlass Ciera: 1993, 1994, 1995.
You can find the EGR vacuum solenoid test here:
Symptoms Of A Bad EGR Valve
As you're probably already aware, the exhaust gas recirculation (EGR) valve is designed to allow a metered amount of exhaust gas into the intake manifold.
Recirculating the exhaust gas (which is oxygen free) back into the intake manifold reduces the amount of oxides of nitrogen the engine produces (when running).
The exhaust gas recirculation should only occur when:
- The engine has reached its normal operating temperature.
- The engine is under load.
- The fuel injection computer commands the EGR valve solenoid to supply vacuum to the valve.
When the engine is idling, the EGR valve should be closed, thus preventing any exhaust gas from entering the intake manifold.
When an EGR valve system failure occurs, the fuel injection computer usually sets the following EGR valve diagnostic trouble code:
- Code 32: EGR System Problem.
You'll also see one or more of the following symptoms:
- Rough idle.
- Bad gas mileage.
Important Testing Tips
TIP 1: The EGR valve can get very hot (when the engine is running). Start the EGR valve test with a cold engine.
TIP 2: You may need to remove the EGR valve to test it. You can reuse the same EGR valve gasket if it isn't damaged.
Whether you reuse the same gasket or install a new one, you must install the gasket dry. In other words: DO NOT use any sealer (like RTV Silicone) on it.
What Tools Do I Need To Test The EGR Valve?
The most important tool you'll need to test the EGR valve is a vacuum pump.
If you don't have one, you can borrow one from your local auto parts store (for a small deposit that they'll return to you once you return the tool -AutoZone, O'Reilly Auto Parts).
If you'd like to buy one, this is my recommendation: Actron CP7835 Vacuum Pump.
TEST 1: Checking For Continuous Vacuum To EGR Valve
The fuel injection computer is the component that controls the EGR valve (to open or close) by commanding the EGR vacuum solenoid to apply or release vacuum to the EGR valve.
The EGR vacuum solenoid has two vacuum ports. One port connects to the throttle body on the intake manifold.
The other vacuum port connects to the EGR valve and should NOT have vacuum with the engine idling.
For our first diagnostic test, we'll check if the vacuum hose connecting to the EGR valve has a vacuum when the engine is idling.
IMPORTANT: Be careful and take all necessary safety precautions while working around a running engine. Think safety all of the time.
These are the test steps:
Disconnect the vacuum hose that connects to the EGR valve vacuum port.
Leave the other end that connects to the EGR vacuum solenoid connected to it.
Connect a vacuum gauge to the vacuum hose you just disconnected from the EGR valve.
NOTE: If you don't have a vacuum gauge, don't panic. You can still check to see if vacuum is present in the vacuum hose.
Start the engine and let it idle.
The vacuum hose (that connects to the EGR valve) should not have vacuum.
Let's take a look at what your test results mean:
CASE 1: Vacuum WAS NOT present. This is the correct and expected test result since manifold vacuum should NOT be present when the engine is idling.
The next step is to apply vacuum to the EGR valve while the engine is idling. For this test, go to: TEST 2: Applying Vacuum To The EGR Valve.
CASE 2: Vacuum was present. This is a problem since vacuum should not be present when the engine is idling.
One of two possibilities could be causing the vacuum in the hose. Either the EGR solenoid is defective, or the vacuum hose is attached to the wrong port on the EGR solenoid.
Your next step is to check that the vacuum hose connected to the EGR valve is routed correctly. If the vacuum hose is going to the right place (the EGR vacuum solenoid), your next step is to test the EGR vacuum solenoid.
You can find the EGR vacuum solenoid test here: