How to diagnose a stuck open EGR valve?

How to diagnose a stuck open EGR valve?

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 remove the EGR valve from its place on the intake manifold and make sure it’s valve pintle is not stuck open. For this test, go to: TEST 2: EGR Valve Pintle Stuck Open.

Where is the EGR valve on a 4.3L engine?

Some of these engines did not have an EGR in 2002 but if it did it would be in the diagram below. The 4.3L engine’s EGR valve is located on the top, front of the engine. EGR valve is pictured below.. If you need replacement procedures just let me know..

Why is my exhaust gas recirculation valve not working?

After miles of service, the exhaust gas recirculation (EGR) system — especially the EGR valve — will lead to engine performance problems due to carbon buildup, components mechanical problems, or vacuum hose leaks.

How to test an EGR valve with a hand mirror?

As you do this, watch the valve diaphragm movement. Use a small hand mirror for this, if necessary. If the stem or diaphragm doesn’t move, disconnect the thin vacuum hose from the top of the valve. Place your finger on the opening of the vacuum hose you just disconnected. Increase engine rpm again as you did in the previous step.

How does the ignition work on a S-10 Blazer?

Troubleshooting the ignition system in your S-10 Blazer begins with a basic understanding of how the system works. Electrical power is supplied to the primary coil of your ignition coil by the ignition module, generating a magnetic field around the secondary coil in the ignition coil.

What does it mean when the EGR valve does not have vacuum?

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.

How to troubleshoot ignition system on Chevy Blazer?

Remove the coil wire from the coil, and hold the 12-volt test light close to, but not touching, the secondary coil tower that the coil wire was plugged into. Turn the ignition to the “Start” position and watch the coil. A bright spark should jump from the coil tower to the test light.

What to do if spark doesn’t work on S-10 Blazer?

If the spark is weak or doesn’t happen, replace the coil. Remove the plug wire from a spark plug, leaving it attached to the distributor cap (or coil pack on S-10s with distributor-less ignition systems) and turn the ignition key to the “Start” position. A bright spark should cross an inch or more to the engine block.

Can a bad EGR valve cause poor acceleration?

Answer: The EGR could be stuck open. If the engine is fed exhaust fumes continuously, this can overheat the valve, cause poor acceleration. Check the EGR system and see if a bad vacuum solenoid is keeping the valve opened. Check the control circuit as well.

Where is the vacuum inlet port on an EGR?

One side of the EGR vacuum solenoid (the one that has only one vacuum inlet port) connects to the vacuum port labeled with the letter J on the throttle body. In case you’re wondering, the letter J is embossed above the vacuum port on the throttle body. The other side of the EGR vacuum solenoid has 2 ports.

What causes a rough idle on an EGR valve?

A rough idle may be caused by a faulty ignition coil, a vacuum leak, or an ignition system problem. So before spending money and replacing parts, troubleshoot the EGR valve and other system components to try to narrow down the problem.