Can a bad egr valve cause a lean condition

I suspect the anti-shudder valve ("throttle plate" thingy in the EGR valve assembly) got stuck in the closed position due to clogging buildup, causing the no-start condition. ok well, removing a EGR can cause a decrease in MPG here is the way it works The EGR valve controls a small passageway between the intake and exhaust manifolds. Each term describes a slightly different condition, but the result is usually the same with each, engine damage. If you tap on a sticking EGR valve lightly with a heavy screwdriver it sometimes will reseat the EGR valve pintle. The good news is you can clean it. Usually, a bad or failing EGR valve will produce any these 4 symptoms that can alert the driver of a potential issue. do you think the EGR Valve is staying open causing the lean. You'll notice one or more of the following symptoms That being said, it also depends on how bad an EGR is leaking as to whether the O2 reports a lean or rich condition An EGR that has a small leak (one that would only cause a small shutter at idle for example) could cause the O2 to show rich; because of the inert exhaust gas is displacing the oxygen entering the combustion chamber. The PCV may cause a rough idle, hard starting and lean misfire (which increases emissions and wastes fuel). 6. 7L engines with throttle body fuel injection system: a stuck open EGR valve. This "by pass" will eliminate every other vacuum related component in the system. Absolutely a bad o2 sensor can cause problems with performance. Can EGR vacuum solenoid vacuum leak cause po171 and po174 codes? Racking my brain trying to find the source of the problem. The concept that an O2 sensor could cause a misfire seemed crazy to some people I talked to, but my gut feeling was that the forum post I read was right. in idle speed would indicate a faulty EGR valve. on 16v misfire. These may all be from the PCV but I also see issues with the intake gaskets and bolts on that engine. . reducing the ignition temperature and lowering the pressure to produce less nitrogen oxide. would add cold air into the fuel/air mixture causing a lean condition  Mar 7, 2018 FIXD explains symptoms, causes, and severity of code P0171. If it were my car, I would start with a valve adjustment because of the age, mileage and problem. Carbon on the intake valves and/or ports, which typically causes a transient lean condition Many lean running problems arise from carelessness in inspecting or . Fuel System A malfunctioning fuel system can reduce the amount of fuel coming into the engine, causing a run lean condition. Photo of EGR Actuator (DPFE Sensor wiring and a hose removed for clarity): The EGR Valve is a vacuum-operated gate that opens up to allow exhaust gases to travel from the exhaust manifold to the intake manifold for recycling. If the PCM detects a lean or rich condition caused by a bad PCV valve, it will turn on the check engine light. Are the ports blocked? Is the EGR operation faulty? Are there vacuum hose issues between the vacuum source to the EVR, the EVR to EGR or the EVR gummed up? Last cause would be a faulty DPFE if all else checks out good. If the readings return to normal, there is a vacuum leak. Low fuel pressure can cause more than just one cylinder to misfire. On modern computer controlled engines this will cause the computer to turn on an amber check engine light which will give a trouble code of “system too rich” or “system too lean” Either condition will result in poor fuel mileage or possible engine damage. This will cause lean misfire and set a random misfire code. 1. System Too Lean (Bank 1) What does that mean? Basically this means that an oxygen sensor in bank 1 has detected a lean condition (too much oxygen in the exhaust). When this happens, the PCM (Powertrain Control Module = Fuel Injection Computer) will think there's a major vacuum leak and this will set the DTC's P0171 and P0174. Inspect the vacuum hose between intake manifold and charcoal canister purge valve. This occurs on acceleration with the engine under a load. If this is the case, your computer may generate a P0171 or a P0300. If the mixture is too rich (too little oxygen) or too lean (too much oxygen) than the oxygen Neglecting to replace a bad oxygen sensor will usually result in damage to your What symptoms lead up to the no start condition? . e. Some will produce a whistle or whine and others can produce a low moaning noise. In addition, fuel pressure is a major factor in this too. 2. I would inspect the air filter for dirt or tears along the edges which seal and force air through the filter rather than around it. I've changed out wires, plugs(dbchked gap),EGR pcv valves,coil,MAS 2x,02 sensor(upstream) Thus a lean air/fuel ratio of, say, 16:1 would translate to a lambda value of After all, CO, normally the indicator of a rich condition, is considerably lower This is obviously a lean mixture, in this case caused by a lazy oxygen sensor and a bad plug The EGR valve receives vacuum at the proper time during a road test. Air leaks in the purge-control valve vacuum plumbing have a leaning effect on the fuel mixture and can cause lean misfire, idle problems This means the EGR valve is closed at idle. And always check for after- market modifications. After activating this valve, the computer looked for a lean condition immediately, to confirm the valve was working. Low Fuel Pressure Causing A Lean Condition. There was a vacuum solenoid valve which the computer periodically opened to apply more than the usual amount of vacuum to the EGR valve. Cleaning the EGR valve seat and stem may eliminate the sticking problem. The same thing can happen if the pintle inside the PCV valve sticks shut. 0L, 5. If the EGR valve is leaking to vacuum slightly, it can cause a rough idle condition. Illuminated check engine light: The powertrain control module (PCM) monitors the engine’s air-fuel mixture via oxygen sensors. When the EGR valve goes bad, it must be replaced. But with its current configuration, with the EGR hooked directly to the intake, will that cause it to be Wide Open all the time? Can that cause any rich conditions or poor mileage? I've read a few suggestions here that it could cause a lean condition too. EGR valve stuck open or excessive EGR flow rate; EGR modulator bleed plugged. Although not too common, an EGR valve can also be the source or contributor to a lean condition. 0L. The lean condition can be caused by a vacuum leak, which . Believe it or not, the fresh air on many sensors actually travels through the wiring insulation! Anyway, a voltage closer to one volt indicates a rich condition and closer to zero indicates lean. No more engine light, no more stupid egr, and by looking at it you can't tell it's blocked if you cut the tin to it's curvature. Check for loose mounting bolts or a damaged gasket under the valve. Canister purge can throw either a rich(172) or lean(171) in this situation depending on whether or not the canister vent (this is different than purge) is open or closed if the purge is stuck open. A failed PCV valve may also cause noise. And when the EGR valve gets stuck open, it'll cause a rough idle condition that may hard to diagnose. If the diaphragm under the EGR valve has ruptured you'd get a straight vacuum leak plus lean condition if vacuum actuated. And also because it would mean that you don't have a problem with your DPFE sensor that open the valve all the time. Best Answer: Anybody that says an EGR can affect an 02 sensor should not be trusted to give advice. Is that the same for Chevy? Can you block the egr off like you can with Ford? I was told NO that it would cause other codes being thrown and would make the truck run like crap. You see, there can be a few things that can cause this p0171 lean code. If the fuel pressure is too low, then all cylinders will run lean causing it to misfire. This tutorial addresses a very common problem I've seen on the 1987-1995 GM 4. Replaced fuel pump and filter (did have a fuel delivery issue due to weak pump). Loss of exhaust gas recirculation (EGR) is a common cause of detonation (spark knock) because EGR has a cooling effect on combustion temperatures. (or gasket below it cracked? or any EGR piping leaking or missing or cracked gaskets. After changing plugs, wires, ign coil pack, it's still there. EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders. . Honda 2000 Odyssey 0172-0170-1491-030 codes This has been going on for a long time. A damaged EGR will make the engine light turn on, thus indicating towards Here, if the engine light turns on, with a lean-mixture trouble code on It is because rough idle when warm can either be caused by one faulty . You can check most of the sensors, and valves, with a digital multimeter. The sensor regulates the amount of EGR opening at various coolant temperatures and manifold vacuum if it's vacuum actuated. d - Pinched or restricted fuel return line is the LEAST likely cause for spark knock or detonation because it is a fuel related issue and will not cause a lean condition, which is a fuel related cause for detonation. the valve is most likely bad. Dirty injectors can also restrict fuel delivery and cause a lean fuel condition. On many engines, a missing catalytic converter will prevent the EGR valve If all of the injectors are affected similarly, the most likely cause is a bad ECM ground. You do usually need an EVAP smoke machine to test it properly or remove them to check it. The unmetered air can cause the computer to set the code because there’s more Oxygen than expected or calculated. In this article, we’ll show you how to clean an EGR valve. When a spark plug does not fire and ignite the air/fuel mixture in the combustion chamber the unburned oxygen results in a lean condition detected by the O2 sensor in the bank associated with the bad plug. The increase in duty cycle permits more vacuum to get in EGR valve thus  Jan 18, 2016 I removed the egr valve, put a vacuum line and sucked on the line, egr held The EGR crap can carbon up badly - I mean 'the stuff looks like coal' bad. The following list of problems could cause high HC levels on fuel injected vehicles. An EGR valve that fails to close at idle is another common cause of stalling. Jan 27, 2019 A rough idle may be caused by a faulty ignition coil, a vacuum leak, or an . The causes are similar to those that can burn a piston: a lean fuel mixture, over-advanced spark timing, a bad knock sensor, low octane fuel or anything that causes the engine to run hotter than normal. An idle surge can be caused by multiple phenomena. A lean fuel condition may be due to a vacuum leak/s and/or defective fuel The EGR system consists of an EGR valve, EGR pressure sensor, vacuum is not working efficiently, (i. A reading greater than +10 indicates the powertrain control module (PCM) is trying to add fuel to compensate for a lean condition. If the mixture is artificially enriched by injecting propane into the induction system, an engine running lean should speed up and the vacuum reading should rise. If the pintle inside the PCV valve sticks open or the spring breaks, the PCV valve may flow too much air and lean out the idle mixture. The source of a vacuum leak can be one of many things. We did not cover everything, but at least you get the idea of the lean condition and what can cause this code. SOURCE: EGR Valve, O2 Sensor. Pull the small vacuum hose off. To determine if the lean condition is the result of a vacuum leak, bring the engine up to about 2,000 RPM. Page 3 of 3: Troubleshooting P0171 and P0174 (GM 4. When the vacuum increases off idle, the EGR valve opens and mixes exhaust gas with the fuel-air mixture. Best Answer: yes if egr vave is not closing it will cause severe lean condition making it hard to start, the egr exaust gas recirculation valve it designed to open at cruising speeded under deceleration, it introduces exaust gas into combustion chambers to lower temp and nox levels in emmisions, nox= oxides of nitrogen Best Answer: yes if egr vave is not closing it will cause severe lean condition making it hard to start, the egr exaust gas recirculation valve it designed to open at cruising speeded under deceleration, it introduces exaust gas into combustion chambers to lower temp and nox levels in emmisions, nox= oxides of nitrogen Inspect the Exhaust Gas Recirculation known as the EGR valve to determine whether it is clogged or stuck open. What Are the Symptoms of a Bad EGR Valve? The most common symptoms of a bad exhaust gas recirculation valve are rough or misfiring idle, detonation, stalling and hard starting. Stuck-closed EGR valves can also caused stalling engines when warm especially if the EGR poppet valve itself won't move because of carbon build up on the area where the exhaust gas are flowing. Temperatures in the combustion chamber can get hot. As a result, it will allow too much exhaust to be sucked back into the intake manifold. that solenoid valve can do the same thing. One additional thing I noticed. could an erratic check valve on the brake booster cause the lean condition? 2. EGR Valve The EGR valve is designed to cool exhaust gas by burning exhaust for a second time within the intake system. When it didn't see that, it assumed my EGR valve was not opening. Egr is one of the worst things chevy did to these engines, it was so bad that in 2002 they didn't put egrs on them anymore. Vacuum hoses over time can become dry and brittle. Remove the small vacuum hose from the vacuum pump check valve located at the large line going to the brake booster. The EGR valve works by routing a small amount of exhaust back into the combustion chamber. What to do? Thus, a bad sensor may set a P0401 code (insufficient EGR flow), or it may not set an EGR code but a P0171 and/or P0174 lean code instead. This is where the EGR (exhaust gas recirculation) valve comes in. The cause of the P0401 code in most cases turns out to be a bad DPFE sensor, not an EGR valve problem or an EGR valve that is plugged up with carbon (though this can also set a P0401 code). If an engine is not getting enough fuel (this is called “running lean”), due to fuel pressure ( regulated by It's also possible your idle air control motor is going bad. an EGR on the other hand generally causes the engine to run poorly, you feel that, and it sets lean condition codes. Most techs are used to doing pressure checks, but many do not routinely check volume. Repair costs vary by year, make and model. Got home and checked the codes, and got the above code (P0171 - Fuel Trim System Lean Bank 1). Thus, a bad sensor may set a P0401 code (insufficient EGR flow), or it may not set an EGR code but a P0171 and/or P0174 lean code instead. A clogged fuel filter can reduce both fuel delivery and fuel pressure. This can cause the valve to become blocked and inoperative, or it may start to leak. But if the purge control valve leaks, it can create a rich fuel condition that increases carbon monoxide emissions, causes surging and causes poor idle. When the valve opens, intake vacuum draws exhaust through the valve. A lean exhaust condition, not faulty oxygen sensors,  A wide range of factors can contribute to or cause a lean air/fuel mixture, which . Or, a defective coolant sensor may be telling the PCM the engine is colder (or warmer) than it really is. The easiest way to verify the problem is to temporarily block the vacuum source to the PCV valve and see if the noise changes or goes away. Almost any sensor that monitors airflow or fuel pressure can cause a lean condition. Inspect the exhaust system for leaks between the engine and the O2 sensor as well. On some vehicles, a bad PCV valve can cause oil to blow onto the air filter element. If this fails, replace the EGR valve. The checks are in the repair manual. Many regular grades of gasoline do not contain adequate levels of detergent to keep the injectors clean. I ordered a brand new O2 sensor from 1AAuto. You can still have a stuck EGR valve, to check it, touch the valve after 5 mins of idling, it should be cold. How will you know when the egr valve is bad on a 1994 Chevy blazer? The third step would be to check your coolant temp sensor as this can cause to rich or lean a condition and mess up your idle . I did catch a code for EVAP small leak the other night (went away on it's own). A weak coil or excessive rotor gas inside a distributor would affect all cylinders, not just a single cylinder. The 16v engine, is MAF based, all air leaks from the MAF to the head intake valves will cause a lean condition, if the ECU can not correct it and for sure WOT (wide open throttle) EGR MAIN leaking. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the  A/F Ratio too Rich: possible problems, conditions or causes get's out only partially burned because of the poor mechanical condition of the engine. With the Engine Cold, visually and physically check all Vacuum Hoses. If you don’t have a scan tool, you can visually The terms valve clatter, pinging, pre-ignition and detonation describe the strange rattle or knock coming from an engine. Intermittent stalling can also be caused by a bad idle air bypass motor or a idle speed control motor. My car has an automatic transmission. Car starts fine, but has rough idle and sounds like it is miss firing. When I disable the EGR it stops. An EGR valve can fail in two ways: It can be open all the time, or it can be closed all the time. These sensors have a pretty large failure price when a vehicle has much more than about 60,000 miles about the odometer or is more than five or six many years outdated. FUEL -LEAN CONDITION EVAP SYSTEM (duhlol) And EGR one I am used to fords and you could normally clean them out and be good for awhile. When the EGR valve is clogged or malfunctioning, it can cause irregularities in engine performance such as rough idling or valve knock, indicating that the EGR valve should be inspected. The p0171 is a lean code, and the p0401 is an EGR code. An open EGR valve, when it shouldn’t be, can trick the MAF sensor and cause a lean mixture. There's a simple test for EGR valves. EGR valve stuck open; Burned exhaust valve; Misadjusted throttle body air/fuel mixture; or Misadjusted carburetor idle mixture. Lean Mixture Code Step 2 - Un-metered air which enters the intake system of the engine can cause a lean mixture code to be triggered, inspect all vacuum lines for cracks or dilapidation. were low, as technician A stated, the engine would have a lean condition. A sticking EGR pintle is common on 1982-1991 cars. Engine Performance Issues Idling and stalling problems can really add stress to your daily commute. Recirculation of the exhaust leads to a gradual accumulation of carbon particles inside the inlet. Ok . now have 107,000 miles The DTCs are normally P0172 system too rich (bank 1) (one causing freeze frame) and P0170 Fuel trim (bank 1) and sometimes 1491 EGR valve lift sensor insufficient flow detected If I let it go long enough I start getting codes P0300-04-05 2000 Honda 3. com and it was at my door the next day. A leaky EGR valve can also have the same effect as an air leak. The most common cause of a vacuum leak is a leaky hose. A PCV valve leak can cause the air-fuel mixture to run too lean, and this will cause a rough idle. Tonight when it did it, I happened to get a green light at the same time and started to proceed, and the check engine light came on. Next use a 18" length of vacuum hose and jumper directly to the N-75 solenoid back to the check valve. After research on the net I find that the EGR paths go to individual cylinders in the lower intake manifold. The 1984 engine uses a manifold vacuum source to operate the EGR valve so a strong vacuum flow from a stuck open control valve solenoid would allow EGR to flow at idle. Checking the Intake Manifold and Plenum Gaskets for leaks with Carburetor Spray. But I still had the misfire. A dirty MAF can cause a lean condition. 3L, 5. The computer was giving off a code 13 which is the O2 sensor, but i also herd that the EGR valve can cause the O2 sensor to go off. The P0171 is one of the more common trouble codes. When the vehicle sits at idle for prolonged periods, high levels of vacuum at the intake manifold result because the throttle valve remains closed. 7L). Egr valve stuck open and causing lean condition Symptoms of a bad EGR cooler How to Diagnose OBD II Fault Codes P0171 and P0174 Leaking Intake and EGR Valve (06 Ford A bad fuel pressure relay can also leak pressure and prevent an otherwise good fuel pump from delivering full pressure to the injectors. With you having a 171 and not a 174 it's very possible it's the cause of your problem if the vacuum line for the purge is feeding into the intake by a bank 1 runner. Therefore the most likely cause of P0171 and P0174 codes is a vacuum leak. Evap canister & Purge control valve. Both are lean codes meaning the O2 sensors were reading a lean condition. A leaky EGR valve can act like a vacuum leak and cause a lean misfire at idle. It manages the chemical and thermal inevitabilities of engine use and keeps the engine running smoother for longer. 5. Feb 5, 2015 Car running “rich” or “lean” means too much or insufficient fuel supply Either condition will result in poor fuel mileage or possible engine damage. Another thing that can cause your p0171 lean code would be incorrect valve timing. If an EGR valve sticks open the engine will idle very roughly or not at all. On some engines, this kind of problem may not appear until the engine warms up. 7:1 air fuel ratio. "exhaust gas recirculation (EGR) is a nitrogen oxide (NOx) emissions reduction technique used in petrol/gasoline and diesel engines. Unwanted EGR flow at idle, even in very small amounts, causes a type of  Jan 7, 2016 When the EGR valve has an issue, it can cause problems with the flow and operation of the EGR system, which can lead to increased  I understand why a EGR valve stuck open causes a poor idle but I have . You can check the O2 sensors by monitoring their voltage output with a scanner but its unlikely that both banks would go bad at the same time. A vacuum gauge can tell you a lot about an engine's condition, similar to a full leak down test - but in a much easier way. These can throw a wrench into the works! The only other possibilities (however unlikely), are wiring issues, computer concerns or a bad O2 sensor! There now that I've said it, on to rich codes. I hoped you learned from this article as I tried to keep it very basic. Exhaust Gas Recirculation Valve (EGR) In my neck of the woods, this is the current reigning king of the “snap-judgment” codes. Of course the misfire codes can come up if your symptom doesn't go away, because you still have the symptoms ;). If the EGR valve is stuck open or can’t seat because of carbon buildup under the valve. If some plug up the total EGR goes to the only open paths which could put a lean condition on only 1 or 2 cylinders. The rubber deteriorates and can leak causing a vacuum loss. If htis answer helps please hit the ACCEPT BUTTON or ask for more help. I installed a new PCV valve, (had a spare in box but I think original was fine) and also a Steeda oil catch can I had in a parts box. A Bad EGR Valve. We will cover more about this p0171 lean code and other possible causes at a later date. You just need to find the cause within this simple path between the exhaust manifold and the port behind the EGR valve. How To Get A Car To Pass Emission Testing. An EGR valve which sticks open can cause a lean condition. This will cause a continuous flow of exhaust gases into the intake manifold. On most vehicles, the engine idle is usually determined by the computer of the vehicle, but for some, you need to have it checked to make sure it is always on par with the recommended settings, especially if the vehicle just had a tune up. P0171, P0174, P2195 are all for lean running condition. The PCV valve works in an extreme environment in your engine, and over time can get filled with sludge and dirt. bad radiator, thermostat, hoses) high NOx will be created. To diagnose many of the problems, you will need little more than a test light, a volt meter, a vacuum gauge and maybe a can of brake clean. as far as using a vacuum gauge is the spot on the manifold the only place I can plug one in? 3. 0 random misfires can a bad egr valve cause this book says check terminal 1an2 ,1an3 if high restance - Honda Cars & Trucks question sure, I can copy and paste from wikipedia. Once it's all back together plug it back in. Yes a hole in the PCV will cause a vacuum leak and those codes. The PCM responds by increasing EGR flow, which may keep the EGR valve open longer than usual creating a lean condition in the engine. The computer uses this valve to constantly adjust fuel trim to maintain a 14. Certainly, the valve can be bad AND you have HI,I have a 1996 Pontiac Grand am that has two codes P0401 and P0171 can the two be relayed I know one is EGR flow insufficient and the other is fuel system lean. A rich mixture will cause the vehicle to run hot. The most common culprit is carbon buildup on the throttle body, exhaust gas recirculation (EGR) valve and idle air control (IAC) valve. But it shouldn't cause a no-start condition! An anti-shudder valve stuck in the closed position WILL definitely cause a no-start condition. This results in the reduction of nitrogen oxide emissions. Well, let me ask you, what can cause an engine to run lean? if one of the sensors on your engine was bad not allowing enough fuel into the engine Most likely possible causes for this P0171 bank one lean condition per manufacture. Which condition does NOT point to a potentially failed EGR valve? Sep 5, 2017 A bad EGR valve can cause serious problems. 0L, and 5. What can cause this code to get set? Either a lack of fuel pressure or insufficient fuel volume can cause a lean-running condition. So everyone on hear that says a weak battery cannot cause a misfire is wrong especially with a Subaru!!! I recently ran into this exact same problem with my 2013 Subaru Impreza 2. One of the easiest and cheapest ways to check an engine for serious issues is to use a plain ole vacuum gauge. This type of carbon can even be caused by oil consumption, which will also cool the combustion chamber temperature. This can make the engine idle rough, misfire and/or stall. Inadequate volume is a common cause of lean DTCs, especially where freeze frame data points to problems at higher rpms and engine loads. Check EGR Valve. The EGR valve is a component of an automobile’s exhaust circulation system that reduces pollution-causing emissions. In just 3-5 minutes you can know if an engine is healthy or not. There is more danger to the engine operation in a lean condition than for any issue to really What problems does a faulty EGR valve cause? vacuum leak (idle roughness, lean vehicles with vacuum-operated EGR valves , a ported vacuum . ProTech: They can be related yes. Nov 19, 2018 Rough Engine Idle – Common Causes With Possible Solutions · Water Pump Noise – Where Can It Come From – How Bad Is It · Engine Fuel  Mar 1, 2019 Maybe; you need to look at the signs of a bad EGR valve below to lousy fuel efficiency in your vehicle will result in a bad fuel economy. The EGR valve may remain closed while the engine is cold, but it starts to leak when the engine A leak in the exhaust system before the O2 sensor will also cause incorrect readings. A failing control valve solenoid can cause stalling and poor or very rough idle on the 1984 Corvette Crossfire engine. For example, if LTFT B1 is 25% at idle but corrects to 4% at both 1500 and 2500 rpm, your diagnosis should focus on factors that can cause a lean condition at idle, such as a vacuum leak. Checking the EGR Valve can often be a bit tricky without removing them. The mixture at idle is controlled by the idle circuit, which has its own external mixture screws, so the mixture is not lean with the EGR valve closed. Which is cheaper, and surer? You DO have a repair manual, don This can cause a lean air-fuel mixture, resulting in a rough idle or stalling. Lean burn refers to the use of lean mixtures in an internal combustion engine. This would occur after a drive cycle coming to a stop. Air leaks or vacuum leaks can cause a lean condition and are common causes of rough idle, hesitation, stalling and hard starting. Luckily, I already had the special O2 sensor socket but 1A Auto had that for sale as well. 3. Rough idle? A good dousing with throttle body cleaner colud restore an EGR valve to near-mint condition, transforming a harsh idle. If you replace one it is highly recommended to replace both or all four depending on your vehicle. Passing Gas. Any of these conditions can upset the fuel calibration of the engine and cause a stalling problem. When you check it, and it checks good, you know you won’t have to replace it to find out if it is “good”. Repairs can run anywhere from $200 for an EGR tube replacement, to a valve replacement, while EGR passage cleaning costs about $700. or you could look it up. An oily or dirty spot,  How to Detect and Fix Faulty DPFE sensor When these two requirements are regulated, the amount of Nitrogen Oxide emitted can also be controlled. These codes suggest a lean-condition in the engine. The EGR Actuator is an electric device that allows small amounts of vacuum pressure to pass on to the EGR Valve. The 02 sensor faults come from dirty air filters/cleaners and/or bad spark plugs/plug wires. An extremely rich fuel condition can also cause elevated HC and CO at idle, while an extremely lean condition will only cause HC to rise abnormally. The high vacuum attracts oil in the heads to congregate around the valve stems. Causes include worn, fouled or damaged spark plugs, bad plug wires or even a cracked distributor cap. Bad Engine Coolant Temperature (ECT) Sensor Stuck open EGR valve. Any thing from a P0401 Insufficient EGR Flow to a P0402 Excessive EGR Flow will likely result in a shiny, new EGR valve from Brand-X; the problem is that it will not rectify the condition for setting the code. I still have the lean condition, that wasn't itbut it's raining now and the truck more about what is the cause of this issue and I eagerly await any and all  Apr 19, 2019 Next component causing rough idle when warm is PCV Valve. When the EGR valve has an issue, it can cause problems with the flow and operation of the EGR system, which can lead to increased emissions and performance issues. The extra air will give you a lean mixture in the chamber, and without the proper ratios of  Jan 7, 2016 When the EGR valve has an issue, it can cause problems with the flow and operation of the EGR system, which can lead to increased  Dec 29, 2013 There are several OBD-II diagnostic trouble codes which can be Any thing from a P0401 Insufficient EGR Flow to a P0402 Excessive EGR Flow will likely result in a shiny, Concerning the EGR system, the EGR valve is the least likely my crew, and I. When this happens, it doesn't send enough fuel to the fuel injectors to keep the Fuel Injection Computer happy. Ford p0171 AND p0174 lean codes can be set by a undesirable EGR differential stress sensor. The main or its base gasket MUST NOT LEAK. Sep 10, 2015 The EGR valve recirculates gases from the engine to burn again, reducing emissions. Actually there are two kinds of bad EGR valves, with different symptoms. On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1. Unlike some emissions control devices that can go bad without affecting the drivability of the car or truck, a bad EGR valve can really affect the engine's performance or even cause it to stop running altogether. Can that cause any rich conditions or poor mileage? I've read a few suggestions here that it could cause a lean condition too. There are five factors that could cause a lean mixture to occur. This would cause the lifters to raise the valves intermittent stalling condition and lousy . Common Check Engine Light Causes Here is a list of the most common check engine lights (CELs P Codes) and their common causes and common symptoms. Carbon on the throat of the valve will absorb fuel, causing a lean condition and giving a similar result as to the previous lean condition. What is pre-ignition or valve clatter? This type of carbon can even be caused by oil consumption, which will also cool the combustion chamber temperature. A bad EGR valve will cause you problems. This includes not just the O2 and MAF sensors, but the manifold air pressure -- MAP -- sensor, intake air temperature sensor and even the sensor that monitors the exhaust gas recirculation system. We’re talking 2,500+ degrees Fahrenheit hot. Note: If the spark burn lines for all the cylinders are higher than normal (indicating a lean fuel mixture), the underlying cause would be something that affects all cylinders such as an intake manifold leak, leaky vacuum hose, leaky EGR valve, leaky throttle gasket or low fuel pressure (weak fuel pump or bad pressure regulator). This problem will cause the reverse effect in the fuel mixture: rich fuel condition because the added exhaust gas flow is restricted. The other three choices can all cause detonation or spark knock. "Lean misfire" can occur when the air/fuel mixture is too lean (not enough gasoline in the mixture) to burn. How to Diagnose OBD II Fault Codes P0171 and P0174 Leaking Intake and EGR Valve (06 Ford Freestyle) How to Check Bad valve seals will show themselves during prolonged idling at stop signs or stop lights in congested city conditions. If the condition exists in all rpm ranges, the cause is more likely to be fuel supply-related, such as a bad fuel pump, restricted injectors, etc. Sometimes a dirty Mass Air Flow sensor can cause lean or rich codes. My car has 200000 miles. PCV valve Explanation: A lean code is enabled when the computer has detected enrichment adjustments have maxed out, with no results, this inability triggers the lean code. Condition of Use. Bad 02 sensor codes are strictly lean/rich levels. the same can be for the AIR system which injects air into the exhaust system at startup to hep catalytic converters warm up faster. can a bad egr valve cause a lean condition

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