Can a Bad Egr Valve Cause a Misfire
The symptoms of a bad EGR valve include reduced engine power, engine misfires, reduced fuel economy, difficulty starting the engine, and spark knocking.
The Exhaust Gas Recirculation Valve (also known equally the EGR) is a key component of the secondary emissions control system. A bad EGR valve can leave your engine running badly or non at all.
The chief function of the EGR valve is to reduce the nitrogen oxide (NOx) emissions by recirculating a portion of the exhaust gases dorsum to the combustion chamber.
Over time, the EGR valve tin get dingy and blocked with carbon deposits from the exhaust gases. This can eventually lead to the failure of the EGR valve.
six Symptoms of a bad EGR valve
The most common symptom of a bad EGR valve, is an overall reduction in engine performance, especially when accelerating.
This is because a broken EGR valve will often fail or get stuck in the open or partially open position. This ways that exhaust gases are not allowed back into the engine combustion chambers reducing efficiency when more power is needed.
The other most common signs of a bad EGR valveinclude the following.
one. Check Engine Light flashing
One of the possible signs the EGR valve has gone bad, is when information technology causes the check engine low-cal to beginning flashing. If the ECU detects a problem with the emission control system (and the EGR), it may warn you by turning on the check engine or service engine soon lite.
It's commonly safe to go along driving with a broken EGR valve, but you lot should get it checked out as shortly every bit possible.
2. Difficulty during engine first
An engine that keeps cutting out on startup can be one of the symptoms of an EGR valve stuck in the open up position.
A failed EGR valve, stuck in the open position can make information technology hard to start the engine and to keep it running.
Under normal circumstances, the EGR valve should exist closed on engine startup, blocking the flow of gases back into the engine. Information technology should stay like this until the engine warms upward and the vehicle starts moving.
If the EGR valve is not operating properly and allowing exhaust fumes to pass into the combustion chambers, this can crusade the engine to cut out, especially when the engine is cold. If on engine startup there is a strong smell of fuel coming from the exhaust, or the engine keeps cutting out, this may exist caused by a faulty or partially blocked EGR valve.
3. Possible engine misfires
Another sign the the EGR valve has gone bad, is engine misfires. A bad EGR valve may cause random engine misfires if it is causing a vacuum leak in the engine.
Sometimes and EGR valve volition not respond in a timely way to the ECU and will stay open up longer than it should, or open at the wrong time. This can cause a vacuum leak in the intake manifold that tin cause an intermittent engine misfire.
If you run an engine diagnostic, you may run into error codes such every bit P0300, P0100, P0101, P0102 or P0104.
These codes can indicate to leaks in whatsoever part of the air intake system, but removal and inspection of the EGR is a good place to start.
4. Crude Engine Idle
I of the well-nigh mutual symptoms of EGR valve failure is a rough engine idle, especially when the engine is cold.
EGR valves oft neglect in the open position, and this volition allow frazzle gases to recirculate back into the engine when it's non desirable for them to exercise so.
5. Reduced engine functioning
One of the effects of a bad EGR valve is a decrease in engine performance, especially nether heavy acceleration.
If the EGR valve is not responding to the ECU it can affect the power output of the engine. The EGR valve opens and closes in response to the real time conditions of the engine. If it stuck open up this can have an adverse outcome on the air to fuel ratio in the combustion chambers, resulting in a reduced power output.
Information technology tin can also bear upon the functioning of the turbo (if fitted). If the EGR is causing a vacuum leak, this can reduce the efficiency of the turbo, and can crusade premature failure of the turbo if left un-repaired.
6. Engine Spark Knock
1 of the symptoms of an EGR valve stuck in the airtight position is spark knock.
Spark knock is a loud knocking dissonance that can be heard from the engine bay when the engine is accelerating or is under load.
Spark knock tin exist caused by problems with the EGR valve. If the EGR valve has become blocked or the valve is not opening when it should, this will terminate the exhaust fumes from re-entering the engine when needed.
Spark knock tin can occur when the combustion chamber gets too hot or there is a build upward of excessive pressure that causes the fuel to detonate instead of burning smoothly.
1 of the primary roles of the EGR valve is to channel libation exhaust fumes dorsum into the engine to assist lower the temperature in the engine and this can help to prevent spark knock. If the EGR valve is non working properly, then there is an increased chance of spark knock occurring.
Spark knock tin can lead to caput gasket failure, damage to the piston rings, combustion bedroom, the connecting rods and the pistons. Simply cleaning the EGR valve can help to prevent spark knock from occurring.
What Is An EGR Valve And What Does It Do?
The role of the EGR valveis to reduce emissions by using exhaust gases to reduce the temperature in the combustion chambers in the engine.
The EGR valve works by re-routing frazzle gases back into the engine at certain times, usually when the engine is non under excess load.
A typical EGR valve with cooler attached
So does recirculating exhaust gases non damage the combustion procedure? The short answer is aye and no.
Overall engine efficiency will drop slightly, but the inert gases will non modify the air/fuel ratio considering the engine control module controls the operation of the EGR and will adapt fuel delivery appropriately.
This driblet in engine efficiency is offset by the reduction of dangerous nitrogen oxide gases from the exhaust, especially with diesel fuel engines.
By recirculating a small portion of exhaust gases back into the engine, the combustion temperature tin be reduced, under sure weather and this will pb to a drop in nitrogen oxide emissions.
How Does An EGR Valve Work?
The EGR valve is usually installed on the intake manifold close enough to the exhaust in order to recirculate the gases when necessary.
The engine command module analyses the data from several sensors including the engine coolant temperature sensor (ECT), the throttle position sensor (TPS), and the mass air flow sensor (MAF). It uses the information from these sensors to make up one's mind whether or not to actuate the EGR.
On modern systems equipped with a digital EGR valve, the ECU also follows, in existent time, the valve aperture using an integrated EGR pintle position sensor.
Internally the construction of the exhaust recirculation valve is very simple. Some models use a flap design (similar to the throttle body), others use a linear valve design.
The EGR is constantly exposed to the exhaust gases which tend to create carbon deposits over time. A clogged EGR valve may get stuck, producing several problems depending on its final position (open or closed). That'southward why is important to perform routine maintenance on the EGR valve to keep it in skilful status.
Here'southward a video describing frazzle gas recirculation.
Frazzle gas recirculation (EGR) made easy
How To Exam For A Bad EGR Valve
For the purpose of this article, it'due south causeless that you lot accept a bones cognition of safety precautions while working on your vehicle.
You may need one or more of the following tools:
- OBD2 Code Reader
- Digital Volt-Ohm meter
- Professional Automotive Scan Tool.
- Vacuum gauge with proper adapters.
- Manual vacuum pump with proper adapters.
E'er refer to the appropriate OEM literature when possible. Original manufacturer diagnostic procedures should always have precedence over a generic workflow.
one. Preliminary steps
Recommended tools: OBD2 Code Reader / automotive scan tool
> Data problem codes: using an OBD2 code reader take note of any DTC present in the ECU memory. For doing and so you lot only demand to connect your lawmaking reader and plough the ignition key on (engine off), a state usually known every bit KOEO.
> Information trouble codes clear: at present that you lot know what codes were stored into memory you lot need to clear them. This is usually done selecting "articulate codes" in your tool.
2. Visual Inspection
Recommended tools: none
> Vacuum line: on vacuum controlled EGR valves, disconnect the vacuum line and perform a visual inspection of its status. Expect for signs of worn or deterioration.
Remove the EGR valve to bank check physical condition
Pay special attending to possible holes in the vacuum line. Ideally, a vacuum line test using a transmission vacuum pump should be performed. Yous could too use the manual vacuum pump to operate the EGR and bank check that it'due south working properly.
> Frazzle Gas Recirculation valve inspection: perform a thorough inspection of the EGR valve exterior, tubing, and connections. Look for possible exhaust leaks in the EGR gasket and connections. Replace the gasket and/or EGR valve if necessary.
Fix whatever wiring trouble before continuing.
3. Electrical Tests
Recommended tools:digital volt-ohm meter (DVOM)
Of import: there are many dissimilar EGR implementations on the market. The following tests only utilise to digital EGR models. Information technology's highly recommended to find a reliable information source containing the proper wiring diagrams before doing any electrical exam.
> Reference voltage: as mentioned earlier in the commodity, some modern designs include a pintle position sensor. Internally, that sensor is nothing more than a linear potentiometer. Refer to the advisable wiring diagram to place your connector signals. In social club to measure the reference voltage, you volition need to enter in KOEO mode (Key On Engine Off) and turn the digital multimeter dial to "voltage" exam mode. Unplug the EGR connector.
Now place one multimeter lead in a known footing (battery negative is a practiced i) and the other probe tip in the terminal of the EGR wiring harness corresponding to the ECU reference. If there is no voltage (or is below 4V) so you lot must check the continuity and electrical resistance of the wire from the terminal all the mode to the ECU itself.
> Ground exam: this test assumes that you found a good reference voltage coming from the ECU. One time once more, enter in KOEO manner (Key On Engine Off) turn the digital multimeter punch to "voltage" test fashion and place one probe tip on the EGR harness terminal corresponding to the reference voltage and the other on the terminal that should be the ground.
Ideally, the voltage would be the same value as the previous exam. If the difference is greater than ten%, then you will demand to check electrical resistance and continuity of the ground line from the EGR harness all the way down to the ECU.
> Solenoid voltages: electronically controlled EGR valves could use 1 or more solenoids to control de valve aperture movements (open/close). Refer to the appropriate wiring diagram and locate EGR solenoid supply voltage, and/or solenoid command signals (usually EGR SOL High/LOW). Using the digital volt-ohm meter check each voltage.
> Solenoid functional examination: using extreme caution and the proper wiring diagram operate the EGR valve solenoid applying the 12V supply voltage to the corresponding terminal. Perform this examination directly on the EGR (electrical connector asunder) to avoid accidental ECU damage.> Solenoid functional test:
4. Browse Tool Tests
Recommended tools: automotive scan tool with alive data capabilities.
> Exhaust Gas Recirculation Valve live test: depending on the vehicle year and model, using an automotive diagnostic scanner yous can perform a EGR "live examination". First, enter in KOEO mode and lock the EGR related data on the brandish. Depending on your vehicle and scan tool maker you may take several items to check. Focus on the EGR position voltage output, EGR aperture (often expressed as %), EGR solenoid activation, and RPM.
Once you are ready, start the engine to enter KOER mode. Accelerate and deaccelerate the engine. Watch the EGR data carefully. The discontinuity should change depending on RPM, usually, the valve is airtight at idle and opens while accelerating.
> Exhaust Gas Recirculation Valve functional exam: depending on the vehicle twelvemonth, model and scan tool you may exist able to perform a functional examination of the EGR valve. Refer to the scan tool manual for detailed instructions. Basically, the functional test allows yous to open/shut the EGR valve and verify is working properly.
How To Clean A Clogged or Dirty EGR Valve
IMPORTANT: ever read the EGR cleaner instructions before proceeding.
Due to its working atmospheric condition, it's not uncommon to observe the EGR valve clogged with carbon deposits. It can be difficult to forbid the build up, particularly when engines get older and have higher mileage.
There are a couple of different solutions to the problem, depending on the severity of the blockage.
- Clean using a professional EGR cleaner spray: this method has the advantage of existence straightforward and time-effective because you don't need to remove the valve from the engine.
- Using a carburetor cleaner spray: this alternative requires removing the EGR from the engine then clean information technology with a metal toothbrush and carburetor cleaner. This method consumes a lot of time, not to mention the exposure to an ambitious production every bit the carburetor cleaner. However, it's a meliorate option than replacing the valve.
- Replacing the EGR Valve: this is the nearly radical solution, merely inevitably at some point, you lot will demand to replace the valve.
This commodity will presume yous will cull the easier alternative: using a professional person EGR valve cleaner.
> Preliminary steps: warm-up the engine until information technology reaches its normal operating temperature.
> Remove air filter or air intake hose: depending on your engine you will demand to choose a method to admission the air intake arrangement. You will need to spray the production on the air intake. Commonly, its easier to remove the air hose, but exist aware that y'all can't featherbed the MAF sensor or vehicle volition be unable to work properly.
> Spray the EGR cleaner into the air stream:increase the engine revolutions to approximately 2000 RPM (consult your production for exact instructions). And so spray the product in short bursts, commonly one 2nd each. The RPM volition drop momentarily.
That's normal, wait a few seconds allowing the engine to burn the cleaner. Repeat the procedure until the bottle is empty. Maintain the 2000 RPM at all times, increase them if necessary to avert stalling. Go along the engine running during 3-v minutes before shutting it off. Ideally, yous should perform a test drive, don't exceed 3000 RPM though.
If the spray cleaner doesn't ameliorate the EGR operation y'all may need to service the valve. As explained above that implies removing the EGR from the engine and clean it using a carburetor cleaner. A highly clogged valve will not be recovered fifty-fifty using this kind of products. If that's the case you will need to replace it.
Bad EGR valve replacement toll
It can cost between $200 and $650 to replace the EGR valve on a vehicle.
The cost can vary greatly, depending on the model and age of the vehicle, and the type of EGR valve that is fitted.
Replacing the EGR valve at domicile yourself is not a difficult job, and can save you lot a lot of money, specially if you fit a refurbished EGR valve.
Here are some example EGR valve replacement costs for 14 popular vehicles.
| Vehicle Model | EGR Plumbing equipment Labor Cost | Replacement EGR Cost | Total Price |
| Ford F-Serial | $40 – $60 | $160 – $220 | $200 – $280 |
| Chevrolet Silverado | $30 – $40 | $230 – $365 | $260 – $405 |
| Ford Focus | $80 – $100 | $120 – $220 | $200 – $320 |
| Toyota Camry | $l – $70 | $270 – $300 | $320 – $370 |
| Toyota Corolla | $80 – $100 | $260 – $400 | $340 – $500 |
| Nissan Altima | $thirty – $fifty | $190 – $230 | $220 – $280 |
| Honda CR-V | $75 – $100 | $220 – $370 | $295 – $470 |
| Honda Borough | $50 – $70 | $250 – $320 | $300 – $390 |
| Honda Accord | $50– $70 | $210 – $280 | $260 – $350 |
| Ford Fusion | $70 – $100 | $170 – $190 | $240 – $290 |
| PT Cruiser | $45 – $threescore | $195 – $200 | $240 – $260 |
| Lexus RX300 | $60 – $lxxx | $310 – $420 | $370 – $500 |
| Nissan Pathfinder | $120 – $150 | $220 – $345 | $340 – $495 |
| Subaru Impreza | $150 – $180 | $220 – $470 | $370 – $650 |
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Source: https://themotorguy.com/symptoms-of-a-bad-egr-valve/
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