How To Test EGR Valve Without Vacuum Pump

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Problems with the EGR system and valves are very likely to occur sooner or later. For a long time, small carbon particles in the exhaust gas accumulated in the intake passages, clogging tubes, and even the exhaust gas channels in the valves of the EGR system. This also affects the plunger mechanism of the valve. An easy test follows to get rid of it. So how to test the EGR valve without a vacuum pump?

EGR testing without a vacuum pump is very simple and straightforward. This test will protect you from damaging parts and other components of the EGR system. So keep reading this article to know the essential details and procedure for resolving EGR valve error except for the vacuum pump.

What Does The EGR Valve Do?

To reduce harmful NOx, a specific amount of EGR valve exhaust gas re-enters the system and changes the chemical composition of the air inside the engine. The EGR system has two primary settings. One open and the other closed. The more power the engine accelerates, the more air it will emit. EGR valves play a role in improving combustion efficiency and knock tolerance.

It contains about 80 percent of the nitrogen we breathe. Although it may seem ridiculous to you, the reality is so. This is because the EGR system emits large amounts of low combustion temperature gases which are harmful oxides of nitrogen.

However, once the engine is started, the gases begin to flow slowly as their speed increases. But when this flow pattern fails your engine performance will start to decline which is not good news for you at all. And most of the time the valve failure of the EGR system is responsible for this situation. Therefore, test the EGR valve before the engine is completely idle.

How To Test EGR Valve Without Vacuum Pump

The EGR system is a sensible thing that is directly related to the performance of the engine. Because it will also start to bother the engine operation when it has problems. Here we are presenting the steps to test the EGR valve in sequence.

Find The EGR Valve

Typically, the EGR valve is a round, thick, and metallic disc about 3 inches in diameter. Find out where it is. In most cases, you will find it in the upper area or on one side of the engine. However, this is not always the case with all cars. Some vehicles also have valves under the bottom components. After all, if you can’t find it, follow the car manual. Because each car has its own configuration based on the model.

It’s time to get back to the EGR valve testing process. Let’s see how to do it step by step.

Testing It Manually

Although valve testing with a vacuum pump is common. Not many people know that you can do it manually also. The valve’s strong metal disc has a little diaphragm, spring, and plunger to maintain its normal close position. During the repair, you will find a small underside that will give you the valve opening access.

Firstly, you have to open the valve. This is why you stick your finger at the beginning of the EGR valve opening and press on the diaphragm. Hope you can open the valve easily. If for some reason you can’t reach your diaphragm or move it, there’s no reason to worry. So all you have to do is inspect the valve passages for carbon deposits as if to restrict the movement of the plunger. Proceed to follow the next process.

Testing Valve’s Diaphragm Situation

The diaphragm of the valve suffers from wear and tear. Therefore they can leak exhaust gas. Follow the steps below to know the position of the hidden diaphragm inside the valve case.

  • Apply the parking brake and block all the wheels of the car.
  • Start the engine of the car.
  • Use a can of carburetor cleaner and insert it with a thin straw tip.
  • Now carefully find the small crack in the open part at the bottom of the cleaner and spray it through the diaphragm.
  • If the RPM of the engine increases after you spray towards the carburetor spray valve, then you have to understand the leak in the diaphragm. It is wise to replace it quickly.

Check For Stem or Diaphragm Movement

The processes for testing EGR valve system movement are as follows:

Step 1

First, turn on the engine and wait 15 minutes for the engine to reach operating temperature. 10 minutes is perfect if you are in a hurry.

Step 2

Then increase the engine speed to 2500 rpm. When increasing the RPM, release the accelerator connection by hand. Moreover, press the paddle quickly and take the help of an associate to release it.

Step 3

During this work, check the movement of the diaphragm. If necessary, take the help of a small hand mirror.

Step 4

If the diaphragm does not move, disconnect the vacuum hose from the surface of the valve. Then place your finger on the vacuum hose opening and disconnect it as you did a little while ago.

Step 5

Increase the RPM of the engine again as in the steps above. If you do not notice any change in vacuum pressure at this time, you will understand the problem from the circuit. Now reconnect the vacuum hose to the EGR valve.

Different Categories of EGR Valve

There are several categories of EGR valves. Initially use a vacuum to operate the valve. But now car models are using electronic control systems.

Diesel EGR valve with high pressure: It converts high flow and high soot exhaust gas before entering the diesel particulate filter. Moreover, soot oil can be combined with vapor to make sludge.

Diesel EGR valve with low pressure: It does the opposite of high pressure. This means it converts the exhaust gas when it passes through the filter.

Gasoline EGR Valve: This is equivalent to some high-pressure diesel and removes exhausts. Eventually, the EGR valve itself regulates its flow.


Vacuum pump technology is very significant for testing exhaust gas recirculation valves. But in addition to this, there are other effective ways through which you will be able to test the EGR valve comfortably. Above we discussed multiple ways you can test your car’s EGR valve without a vacuum pump. Hopefully, you will find these helpful. Protection Status
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