A 3-Step Guide to Installing Your Air Inject Check Valve
An air inject check valve is a component of a car's air injection system that takes part in letting fluid pass through the valves for a more efficient combustion in the engine. But despite the fact that the check valve is part of a whole assembly, it does not necessarily mean that it will not get damaged as a single component. There are instances when the air injection check valve becomes defective because of constant wear and tear. Some of the most common problems faced by a check valve are corrosion and overexposure to high temperature. And since most check valves work automatically, there is no way for people to address it but through replacement.
Required skill level: Novice
Needed tools and materials:
Preparing the vehicle
Park the vehicle at a spacious area where you can work comfortably. If in case you are replacing an old check valve, make sure that the car temperature has been cooled down before you start the process. The air injection valve is often exposed to extreme heat, and it could be harmful to begin right away when you have just turned off the engine.
Locating the check valve
Find the check valve on your car. Since it is part of the air injection system, you may find the check valve on the area where the catalytic converter is also placed. The component is quite small, which means that you would have to look through the system carefully, especially if you are doing this the first time.
Installing the check valve
Install the air injection check valve using one of the wrenches that you have. Simply twist the wrenches repeatedly until the valve tightens. See to it that the part is installed properly so it won't be easily removed, especially while the car is moving.
Checking the working condition
Check whether the newly installed valves are working properly. If there seems to be a problem with the part, try to take it out again and repeat the installation problem. If nothing improves, have the vehicle checked by experts in case there are other damages.
Tips and warnings
- Using hand gloves is also an option if you don't want to risk getting hurt while installing the check valve. But if you are more comfortable working with your bare hands, there is also no problem with that.
Air Injection Check Valve Buyer’s Guide
- The air injection check valve goes by the names secondary air injection check valve, air pump check valve, air injection valve, and air pump valve.
- The air injection system is an emissions control component that works by injecting fresh air into the exhaust to burn any unburned hydrocarbons in the exhaust.
- Unburned fuel is more harmful to the environment compared to burned fuel.
- The main task of air injection systems is to make sure there’s enough oxygen in the system to burn hydrocarbons.
- The air injection check valve helps with the operation by preventing the exhaust gas from flowing back into the air injection system.
- Check for symptoms like an illuminated check engine light, failed emissions test, and a foul fuel smell from the exhaust.
- There are two methods of air injection: pumped and aspirated.
- OE air injection check valve replacements on CarPart.com can cost you from $13 to $405.
There have been different innovations and inventions for controlling vehicle emissions throughout the years. One component that has been the subject of debate about whether it is actually needed or not is the air injection check valve. This small device is part of your vehicle’s exhaust system’s secondary air injection system.
Some people have little knowledge about the air injection valve, causing many to overlook its importance. You can face various problems, including a failed emission test, due to a malfunctioning air injection check valve.
What is an air injection check valve?
The air injection check valve goes by the names secondary air injection check valve, air pump check valve, air injection valve, and air pump valve. It is a device that prevents exhaust from flowing back to the air injection system. The air injection system is an emissions control strategy that works by injecting fresh air into the exhaust to burn any unburned hydrocarbons in the exhaust.
The reason why it’s secondary is because cars have a main air injection system called the induction chamber, which was in place long before the exhaust air injection was introduced. However, no one calls the induction chamber the primary air injection system, so the secondary air injection system can also be referred to simply as air injection.
Air injection systems exist because no engine in the world can reach 100% efficiency. Unburned fuel can still reach your exhaust from time to time even with a healthy engine. Unburned fuel is more harmful to the environment compared to burned fuel. The main task of air injection is to perform secondary combustion in the exhaust to burn the hydrocarbons by making sure there’s enough oxygen in the system.
However, due to backpressure, exhaust gas can sometimes force its way back into the engine. This is a problem as it can cause your engine to suffer a number of performance issues, which leads to more expensive repairs. The air injection check valve helps with the operation by preventing the exhaust gas from flowing back into the air injection system.
Symptoms of a failing air injection check valve
Luckily, you can pinpoint a failing secondary air injection check valve through various symptoms. All you have to do is to be aware of them and be vigilant about your vehicle’s performance. Below is a list of the known bad air injection check valve symptoms.
Illuminated malfunction indicator lamp (MIL)
If the engine control module (ECM) detects that the air injection system is operating below the ideal performance, it will trigger the check engine light. A faulty air injection system could be due to a bad check valve that may require immediate replacement. Consider running a scanner and double-check the reading with your trusted mechanic.
Failed emissions test
Since there’s nothing to burn the unburned fuel exiting your exhaust lines, your vehicle will pass on more hydrocarbons to the atmosphere. The increase in hydrocarbons coming out of the tailpipe can cause your vehicle to fail the emissions test.
Foul odor from the tailpipe
A foul exhaust fume odor coming out from the tailpipe is a clear sign of a problem associated with your exhaust system. The fresh gasoline or diesel odor could be due to a leak in the valve’s housing. It’s due to the exhaust gas leaking back into the air injection system.
To avoid expensive engine repairs, replace your failing air injection check valve as soon as you notice one or more of these symptoms.
Additional Information about Air Injection Check Valve
There are two methods of air injection: pumped and aspirated. These two differ according to the way they injection air. A pumped air injection system uses a vane pump to deliver air into the exhaust lines. It is operated by the engine either via a belt or an electric motor and pumps air under light pressure. The pumped air injection system is the one that uses the air injection check valve.
Aspirated air injection, on the other hand, works with the negative pressure pulses to draw fresh air through the aspirator valve. This valve is located in the air injection pump and draws air from the air filter. The drawn air is delivered through the exhaust stream at the catalytic converter. The advantage of this system is the absence of pump-related losses in the supply of secondary air injection. An aspirator air injection, however, only functions at idle, which means it will inject less air within a narrower engine speed range.
How much is an OE secondary air injection check valve replacement?
OE air injection check valve replacements can cost you around $13 to $405. The price range includes a wide array of parts from reputable manufacturers. They are sold individually or in sets of two. For a sure fit, specify your vehicle’s year, make, and model in the filter tab under the search menu to narrow down the list. You may further customize the list by optimizing through the “Refine By” section on the left-hand side.
Air Injection Check Valve Buyer’s Guide
An air inject check valve, with its two openings, plays a vital role in preventing backflow and making sure that fluid enters and comes out of the valve in one direction. However, consumers sometimes find it difficult to get the most efficient check valve in the market because of the variety of brands available. To help you come up with a wise decision, we reviewed two bestselling check valve brands: Motorcraft and Tomco.
The Motorcraft brand is precision-engineered to improve the overall performance of vehicles under the Ford, Lincoln, and Mercury lines. Although the brand also offers check valves that work for other car models, Motorcraft items are most recommended for consumers who are using Ford vehicles given that the brand is developed by Ford Motor Company. Tomco's check valve carries a more generic specification, which allows it to easily fit and function for plenty of other car models.
WINNER: Motorcraft and Tomco
Tomco features an elastomeric O-ring on each of the check valves it manufacturers, which ensures a tight seal for practically any kind of vehicle. The valve is capable of giving a gas-tight seal or a metal-to-metal seal that prevents leak on the system. Motorcraft's check valve, however, uses a more unique version of the seal that works best for Ford models.
Motorcraft offers its air inject check valve within the price range of $40 to a little less than $200. Tomco models, on the other hand, Tomco products are priced way cheaper at about $30 on average.
Although Motorcraft is the more popular brand between the two, we find Tomco's air inject check valve to be a better choice than the check valve from Motorcraft. Both brands have proven to be efficient and capable of improving the overall performance of the vehicle. We observed that the two check valves are durable, uses non-corrosive materials, and can perfectly resist abrasion. At the same time, both brands follow the specifications that are closest to the original parts, which make them perfect candidates as replacement parts. However, we think Tomco's check valve could cater to more consumers than Motorcraft. Also, Tomco's is more affordable and the price could still go lower through discounts.
Choosing the Right Air Inject Check Valve
The job of an air inject check valve is pretty simple: it allows exhaust gases out through the exhaust system but prevents the same gases to enter the engine components the other way. It is essentially a one-way control valve-if it fails to do its job and lets exhaust gases back into the engine system, it may damage your car. When it does fail due to damage over time, the installation of a secondary air inject check valve will prove to be very useful. However, irreparable damage on the valve means you will have to buy a replacement.
What to look for in a check valve
Here is a list of factors to consider when buying replacement or secondary check valves:
- Resistance to abrasion and corrosion
- Valve's service life
- Warranty coverage
You would know it's time for a replacement if you notice too much corrosion on the defective valve. You can try cleaning it with carburetor cleaner, but most of the time you would need to buy a new one. If this is the case, look for one that has high resistance to rust and factors that cause abrasion. Also try to find a replacement that will last a long time given that the valve is exposed to exhaust gases that apply damage to it over time.
The bottom line
Manufacturers with bumper-to-bumper warranty would gladly replace your check valve once it is determined that it needs replacement. However, if you are out of bumper-to-bumper warranty, it is a good idea to check if the emissions warranty is still valid-this should cover the damaged air inject check valve.
You can find check valves that are priced at around $50 - $100. If your local auto parts dealer doesn't have one for your car's make and model, you can order these online and then have them shipped.
How to Clean or Replace Your Air Inject Check Valve
An air inject check valve's primary function is to prevent exhaust gas from finding their way into the air pump system. If it becomes defective, it can cause significant damage to your air pump system and other parts of the engine. The following are the most common symptoms attributed to a check valve's failure:
- In most cars, a "Check Engine" indicator lights up. A code P0410 usually shows up if it's determined that the problem is with any of the air pump system components.
- A defective check valve may cause your car to fail an emissions inspection.
- It may also cause underhood exhaust leak or noise.
Difficulty level: Moderate
Tools that you'll need:
- Jack and jack stands
- Carburetor cleaner
Step 1: Locate your air inject check valve. Open the hood, jack up your car, and with a flashlight look under your car for the exhaust manifold ports. From there, follow the diverter valve and the air injection pipes, which are the two most rear tubes. At the end of these tubes is a small object called the air inject check valve.
Step 2: Remove the check valve by pulling off the hoses coming from it both ways. While you have the valve removed, it would be a good idea to clean the hoses off too.
Step 3:Inspect the check valve-when it is new, it is colored silver, but over time it can turn brown or black. Clean it with carburetor cleaner, put it back in, and start your engine to test if the "Check Engine" light is turned off-that means you got it fixed.
Step 4:If necessary, replace the check valve with a new one by plugging in the two hoses you removed from the old valve.
Step 5:It is also advisable to install a secondary air inject check valve; although it is not required to have one, a backup valve is always a good thing to have on hand.
NOTE: Although a lit indicator and/or a failed emissions test may also mean that there is a restricted passage or air pipe, a defective air pump, or a wiring problem, it is worth checking out if the air pump check valve itself is damaged. Although it is a bit tricky to spot under the hood, don't forgo the chance to inspect it once in a while.