Question: How To Bypass Purge Valve: 5 Effective Steps

A malfunctioning purge valve can wreak havoc on your vehicle’s engine. It may cause less fuel economy, starting problems, increased emissions, engine misfires, and a Check Engine Light coming on. If your vehicle has such symptoms, bypassing the purge valve can help resolve the issues.

So, how do you bypass the purge valve? Note that incorrect bypassing of the valve can cause further issues with the engine. But don’t worry because this article got you covered.

We’ll discuss how to bypass purge valve in five steps to ensure your vehicle gets back on the road. You’ll also learn how to test for a bad purge valve, the effects of bypassing the purge valve, and more.

Question: How Does the Purge Valve Work?

The purge valve is a crucial component of a vehicle’s emission control system. It regulates the flow of fuel vapors generated in the fuel tank to the combustion chamber.

As the fuel from the tank evaporates, it creates vapors that can increase pressure in the tank. This pressure needs to be stored to prevent it from escaping into the atmosphere. Hence, these vapors go to an evaporative canister for storage.

When you start the engine, the purge valve opens up, allowing the stored vapor to flow into the air intake manifold. The vapor mixes with fuel to be burned in the combustion chamber.

Question: Why Is the Purge Valve Important?

Vehicle manufacturers install the purge valve to reduce the emission of harmful gasses. Remember that gasoline contains volatile hydrocarbons that can pollute the air. The purge valve ensures the vapors burn in the combustion to prevent the emission of carbons.

Another benefit of the purge valve is to prevent wastage of fuel. As the fuel evaporates in the tank, these vapors must be stored and used in the combustion chamber. Failure to store and use these vapors would lead to less fuel economy.

Moreover, the purge valve and the entire evaporative emission control system prevent pressure buildup in the tank. Fuel evaporation creates vapors that can accumulate in the tank. If these vapors don’t get out of the tank, they can increase pressure and cause fuel leaks or explosions.

Lastly, a functional purge valve enhances a vehicle’s performance. It prevents excessive fuel vapor from accumulating in the combustion chamber, ensuring the engine operates effectively. An effective engine leads to more power and enhanced acceleration.

Answer: How To Test for a Bad Purge Valve

If the engine acts up and your vehicle experiences poor fuel economy, you should check if the purge valve is the culprit. A multimeter will help you know if the purge valve is the cause. Follow these steps to test for a bad purge valve:

  • Turn off the engine: Ensure you’ve turned off the engine for 15-30 minutes.
  • Disconnect the purge valve: Locate the purge valve and disconnect the electrical connectors.
  • Measure the resistance: It’s time to test the purge valve with your multimeter. Ensure you’ve set the multimeter to measure resistance. Then, touch the multimeter leads on the purge valve’s terminals.

A functional purge valve’s reading should be between 22 and 30 ohms. A reading below or above that indicates issues with the purge valve.

Answer: How To Bypass Purge Valve

Over time, the purge valve might malfunction and fail to release vapors into the engine. When this happens, you can bypass the purge valve before looking for a long-lasting solution.

As a DIY enthusiast, you might want to know the step-by-step process of bypassing the purge valve. Read on to get this job done.

Step 1: Disconnect the Battery

When bypassing the purge valve, remember to disconnect the battery. You can do this by disconnecting the negative cable. The goal is to prevent powering the vehicle, which might result in shorts.

Step 2: Remove the Charcoal Canister

The charcoal canister holds vapors until the purge valve releases them to the engine. You can locate it near the fuel tank.

Start by lubricating the two vacuum lines on the canister using some WD-40. You’ll find one of the lines at the top and the other at the bottom. Use pliers to squeeze, twist, and pull the lines until they come out.

If you have a defective or clogged charcoal canister, uninstall the bolts or brackets holding it into place. Doing so will create a room for installing a new canister.

Step 3: Remove the EVAP Purge Solenoid

Locate the line connected to the side of the EVAP purge solenoid and pull it out. To uninstall the purge solenoid, use a 10mm socket and an open-ended wrench to remove the nuts at the bottom.

The purge solenoid features two engine vacuum lines. One is at the top, traveling above the charcoal canister. This is the line you unplugged at the top of the canister. The other engine vacuum line runs below the air intake manifold. Unplug the end of this engine vacuum line to disconnect it from the purge solenoid.

Then check your assortment kit for a matching cap and use it to cover the vacuum ports.

Step 4: Coil the Remaining Lines

You don’t want gasoline vapor and odor to fill the vehicle base. So, loop the return and supply lines to ensure no vacuum leaks.

The engine vacuum line has a rubber line that can fit on both ends of the ports and the lines. So, flip this rubber line, fit and rotate it on both ends to make a connection. Connecting both ends of the lines and ports ensures no fuel vapor leaks.

Step 5: Monitor the Vehicle’s Performance

After bypassing your purge valve, start the engine and check for vapor leaks in the connections. Then, monitor your vehicle’s performance, particularly the engine’s performance, emissions, and fuel economy. If everything works properly, you’ve successfully bypassed the purge valve.

Question: What Happens When You Bypass the Purge Valve?

After knowing how to bypass purge valve, you might want to know how reliable his method is.

The truth is that there are more effective ways to solve issues with the engine than bypassing the purge valve. This method should be used as a temporary fix. Usually, bypassing the purge valve can present some potential problems.

Below are various issues you might experience after bypassing the purge valve:

  • Check engine light
  • Poor fuel economy
  • Failed emission test
  • Engine running rich
  • Hard starting
  • Engine misfiring
  • Jerky vehicle idle
  • Vacuum leaks
  • Collapsed fuel tank

Question: What Causes the Purge Valve to Malfunction?

Several issues will cause the purge valve to malfunction. They include:

Environmental Factors: Exposing your vehicle to extremely high or low temperatures for an extended period can cause premature valve failure.

Contaminated fuel: Low-quality or contaminated fuel emits carbon-rich deposits that clog the purge valve. These deposits can also accumulate in the charcoal canister and cause it to malfunction.

Wear or damage due to excessive use: The purge valve succumbs to wear and fails over time. Parts in the valve can wear out or get damaged and prevent efficient vapor flow into the engine.

Answer: How to Troubleshoot a Malfunctioning Purge Valve

Instead of bypassing the purge valve, finding a permanent fix is advisable. You can either clean or replace the bad purge valve.

Start by diagnosing the purge valve to determine the cause. If debris or contaminants clogs your purge valve, cleaning it can help fix the issue. But first, consult a professional to know if cleaning the purge valve is safe. Some valves should not be cleaned as they can get damaged.

If you have a valve that’s safe to clean, unplug the wire connection and remove the hoses. Uninstall the purge valve and dismantle it to access the interior parts. Then follow these steps to clean it:

  • Use a small object to poke the hard deposits inside. Be careful to avoid damaging any internal parts.
  • Spray an effective cleaning solution to get rid of the deposits. Avoid exposing the cleaner to the electrical terminals when spraying, as this could result in damage.
  • Allow the cleaner to soak up the deposits for 15-20 minutes. You can then use water to clean the dark particles in the valve.
  • After cleaning, reassemble the purge valve and test the vehicle to see if you’ve solved the problem.

If the vehicle continues to act up, you might have a damaged purge valve. Inspect it for signs of damage and replace it if necessary.

Bottom Line

Hopefully, you’ve learned how to bypass purge valve to ensure your vehicle is running again. And since this valve is part of the vehicle’s emission control system, ensure you’ve bypassed it before driving again.

If bypassing doesn’t help solve the issues, consider a permanent fix. You can clean the valve if dirty or replace it if damaged. Lastly, inspect the purge valve and consider regular maintenance to ensure it remains in good condition.

Leave a Comment