Wells TechConnect Ep. 18 -- What Happens when an EGR Valve Sticks Open?

[@tomastotrenaki]

I have issues with my car running rich after a complete engine restoration... This video helped a lot, now I am certain that my EGR valve is the problem. Thank you very much! Nice demonstration!

[@ozzstars_cars]

The visual demonstration of air/fuel ratio using the colored water and oil is genius. Nice job Mike explaining a tricky subject.

[@GoTechTraining]

Thanks Ozzstar! A visual always helps me. I feel like many of us technicians are very visual people. Kind of helps drive the point home. Mike Becker, Technical Services Instructor

[@haywardsautomotive6156]

Covered all the variables brilliantly Mike and nice touch with the visual. Survey's complete! Congratulations Dad!

[@GoTechTraining]

Thanks Bob! A ton to cover but i'm hoping it was easy enough to follow and made some sense. I tried not to ramble too much, lack of sleep with a newborn can make you do that I'm finding out! Mike Becker, Technical Services Instructor

[@haywardsautomotive6156]

Oh yeah you'll get used to no sleep & then come the diapers :O

[@GoTechTraining]

I'm catching on pretty quick...thanks to my wife! Oh yeh those diapers, pretty soon I'll be master certified diaper changer! Mike Becker, Technical Services Instructor

[@stuzman52]

Nice explanation there Mike and great visuals to help one understand. Congratulations on being a dad and wishing you and your family much happiness.

[@GoTechTraining]

Thanks Stuzman!!! Mike Becker, Technical Services Instructor

[@hemnaswad9177]

Great explanation for free. Good man still exist thankfully. Love you all trainers

[@GoTechTraining]

Thanks for watching Hemn Aswad. Mike Becker, Senior Technical Instructor

[@JoeBob79569]

This is great. I'm trying to diagnose poor running and rough idling on my X-Type 2.2D at the moment, and I'm leaning towards the EGR sometimes getting stuck open. Today I disconnected the power to the EGR, and suddenly my MAF readings jumped from about 5-8g/s to about 12-15g/s while idling, and performance improved considerably. What I imagined in my head was exactly like the way you described here, mixing the liquids. My thinking was that there was a lot of exhaust gas getting mixed with the "good" air, and the car thinks that it has more good air because the MAP is getting a high pressure reading, but the car just doesn't know that some of the pressure is due to too much exhaust gas.. My MAP sensor is right on the EGR valve and I think it's supposed to be a "boost" sensor, as there's also a second MAP sensor just after the intercooler, probably to measure the pre-EGR pressure.

[@jasonmallory4152]

I have an 03 impala that I usually have to feather the throttle (because it struggles to start) but once it starts it will idle real low. And Every once in a while it will start to rev up high on its own sometimes as soon as it starts. I have cleaned the throttle body and changed the idle control valve as well as the throttle position sensor. It has code p0300. It has new spark plugs also.

[@GoTechTraining]

Jason, a P0300 is a random misfire code. Could be caused by a ton of different things...how are the spark plug wires, coils, injectors, compression? Mike Becker, Senior Technical Instructor

[@confidential8738]

Still got the car?

[@konstantinekakabadze2527]

The best explanation I've ever seen. Visual effects make this really easy to understand. Thanks a lot! One question though. Theoretically, if we're talking about electronically controlled EGR valve and old dying car battery, can the dying battery cause stuck open problems? Not exactly stuck open, but "sticky" EGR, when it closes sometimes correctly, but sometimes stuck. After replacing the battery I noticed a power boost around 1500-2000RPM and before that was having "P0402 Exhaust Gas Recirculation Flow Excessive Detected". The motor I'm talking about is HDI 1.6. So just to summarise, my question is if bad old car battery can provide low voltage or something and cause a "sticky" EGR valve problem? Thanks!

[@GoTechTraining]

Hi Konstantine, thanks for watching! I don't think that could be the case. Most of the time the alternator puts out enough charge to keep the system maintained. If you were losing voltage though, sure it could cause some weird issues with the EGR, amongst many other systems. Mike Becker, Senior Technical Instructor

[@konstantinekakabadze2527]

@@GoTechTraining Thank you. Mechanics will take a look in two weeks so we will see what it was. The main dilemma I have at this moment is just to clean EGR, or replace it because no one knows if clearing will solve that I might need to pay twice if it needs to be replaced after cleaning...

[@ggua92722]

Visual was great! It was easier to understand once fluids were mixed. 👍 👍

[@GoTechTraining]

Hey Ggua92722, thanks!!! Glad the fluid demo worked :) Mike Becker, Senior Instructor

[@ThunderbirdRocket]

The ultimate in automotive teaching ! Thanks mate . 👊🏼 🔥

[@W.Khairi]

Wow Man, Great Video , Just shows how complicated engine diagnosis can be, Thanks a lot.

[@GoTechTraining]

Hey W .Khairi, thanks for watching! Mike Becker, Technical Services Instructor

[@salvor1]

Could a stuck open EGR on a turbo diesel be purging charge air into the exhaust creating a low boost code?

[@dimisrambodimisrambo7285]

in an engine that has only a map sensor, what will happen if the egr is stuck open? will the map count less or more in/hg? will it give rich or poor condition?

[@GoTechTraining]

Hello, With a speed density (map only) system. The EGR being stuck open would drop engine vacuum and show less MAP in/hg in the engine. It would also act as a vacuum leak and raise the idle and inject more fuel. Due to the extra fuel and the EGR gas being inert, I would expect to see a rich condition. All conditions would be more prevalent during idle and less noticeable under higher engine speeds. Good question! ~Ryan

[@dimisrambodimisrambo7285]

@@GoTechTraining thank you ryan i just had a vw polo in the workshop and the egr was stuck open and the map shows 27 in/hg at idle and koeo normal 29.9 in/hg this is what i wanted to certify my friend. thank you.of course the car was difficult to drive and did not idle well

[@dimisrambodimisrambo7285]

@@GoTechTraining is there a chance that a stuck open egr will give a poor condition? I have seen it in an opel corsa c but I could never explain it. have you ever faced something similar?

[@jb6574]

When people do egr deletes does that have the same effect as if the egr was stuck closed...does deleting the egr system effect afr

[@GoTechTraining]

Great question. EGR dilutes the mixture. It effectively makes the combustion chamber smaller...reducing power. Yes, EGR can affect the AFR. Mike Becker, Senior Technical Instructor

[@jb6574]

@@GoTechTraining so with the egr open i guess the computer can run a leaner fuel mixture and run a bit more spark advance?

[@GoTechTraining]

It's not really "leaner" mix...it's a smaller mix. The EGR gas takes up room inside the cylinder. Therefore less air goes into the cylinder, then we add less fuel. The mix is still stoic or very close to it. Mike Becker, Senior Technical Instructor

[@ItsAngryDuck]

could egr gases still be in cylinders after changing the egr valve?

[@GoTechTraining]

I don't think so, they would have disapated by then. Mike Becker, Senior Instructor

[@jeffarmer4428]

Great info. Mike . I have one for you , customer has a hard starting problem an said he gives it more gas by pressing on the gas pedal , he said it sputters an back fires in the intake manifold . This is a fuel injected engine . Now , while cranking is this giving the engine more gas or just allowing more air in .

[@GoTechTraining]

Thanks Jeff! Are we talking pedal to the floor or just kind of feathering the pedal? It is defiantly letting in air, reducing the cranking vacuum. As for fuel, it depends on the vehicle I would think. I bet if you were to scope the PW of the injector cranking, then push the pedal you would see the PW expand if the PCM will allow it. Mike Becker, Technical Services Instructor

[@jeffarmer4428]

Don't know , the guy said just giving it a little more gas ! I told him about pushing the pedal to the floor would put it into clear flood mode .

[@GoTechTraining]

Hmmm, I bet that expands the pulse width a little bit. What kinda car? Did you get to the root cause or are you still workin on it? Mike Becker, Technical Services Instructor

[@jeffarmer4428]

The car is a 2002 buick lesabre . I'am not working on it , just trying to help someone out . I haven't heard anything back yet from him. So i don't know what's going on ! If he ever get's hold of me i'll let you know . That would be something to check , if i had a lab scope .

[@GoTechTraining]

Alright, i'd be happy to help if you can get me a little bit more info on it! You gotta get your hands on a scope Jeff, even if it's just a little single channel U-scope from AESwave it's better than nothing. Mike Becker, Technical Services Instructor

[@Thefox2000unit]

Hey, Mike. Excellent vid. Am I right in thinking that if you have an electric EGR (5 wire, 2 for solenoid and 3 for potentiometer) that there will NOT be a DPFE or EVR. That the evr is to control the vacuum to the EGR pintle for movement, and the DPFE is to monitor pintle position. What measures flow in both vacuum and electric systems? Thanks. Fox. N/ W Scotland.

[@GoTechTraining]

Hey Fox, Usually that's the case. No need to have a pressure sensor when there's a position sensor on the valve. Both types of sensors are just to ensure EGR operation. Just 2 different ways of doing it. Some systems didn't even measure flow. Newer electronic systems monitor pintle position. If the pintle is opening, it's flowing. Typically the amount of flow is assumed, not measured. Mike Becker, Senior Technical Instructor

[@Thefox2000unit]

Wells Vehicle Electronics Thank you so, so much for the reply and the answer that flow is "assumed" and not so much measured. Man, I bet you wish I had not happened upon your channel..... 🤣🤣

[@GoTechTraining]

Fox, NO WAY! I love answering your questions! Mike Becker, Senior Technical Instructor

[@moshazza5684]

hi mate, i have a skoda 2,0 tdi cffb engine. it cut out on me in the morning at junction, wouldnt start again and only cranked. i got it started later on in day using easy start spray. and i drove it half a mile, no issues. i went to start it again later in evening, same issue...started and clocked out when i tried to rev it. i described symptoms to a mechanic and he said most likely the egr is clogged or stuck open thats why it wont start . is this right?

[@Godisgr8always]

My 2002 Ford Focus se idles rough on cold start ONLY on cold start and it doesn’t go away until the engine warms up. And it feels like the engine starving for air.

[@gilbertnickerson1512]

cause and effect on the operation of the 02 sensor

[@miguelangelguerreroflores3284]

do oil inside the intake manifolt. the has a MAP sensor will afect is performanse? oil is ocupaing space inside the manifolt so we dont get the right amount of oxegen.

[@GoTechTraining]

Miguel, due to the PCV system there is commonly a small amount of oil in the intake manifold. Generally it does not affect performance, but yes, you're right. It is occupying space that could be taken up with oxygen. Mike Becker, Senior Technical Instructor

[@johnlira3316]

Can it cause white smoke in tail pipes

[@GoTechTraining]

John, most of the time white smoke is caused by coolant burning. Is the vehicle going through engine coolant? Mike Becker, Senior Technical Instructor

[@johnlira3316]

NGK Technical Training no coolant level is ok no over heating problem i replaced spark plugs wires and pcv valve car is an 2004 grand am still has the factory Egr and fuel presure regulator

[@GoTechTraining]

Hmm interesting. Is the check engine light on? Mike Becker, Senior Technical Instructor

[@johnlira3316]

Yes its on

[@elkopanare7732]

Nice explanation. Can tell you what happens in the real world yesterday with my Mazda cx 5 2.2 diesel. After a short 2-3 km ride (after cold start) i stopped for 5 mins.. EGR stuck at open position.. at this point but i was not aware of this until i started the engine. Immediately noticed unstable idle and misfires aand a lot of smoke. The car was choking literally. It's winter so my fist assumption was poor diesel - blocked fuel line or filter or something so.. decided to rev it a bit .. it caused a lot of smoke and it sounds like the car has lost a cylinder... tried to run it but it was struggling to reach to second gear... stopped and called a road help that pulled me to the service and once we dropped the car there it started perfectly without any issues :) Just FYI there was no check engine light or any error code logged. Anyhow the car will be serviced and the EGR body and intake manifold will be cleaned due to high carbon buildup.

[@wyattoneable]

Outstanding explanation and visuals. I'll do the survey next!

[@GoTechTraining]

Thanks Wyattoneable! Mike Becker, Technical Services Instructor

[@rogereastman3187]

I'm not interested in the legal factor with this question. It seems to me if a guy was to delete the EGR system, it would alleviate one more headache. Your thoughts?

[@alexmessina7652]

Great analysis of a tricky problem, Mike. To add another possible, complication, what effect is there with a dual map/maf system, assuming there is no egr position sensor ... Will ecu program preference maf or map??

[@GoTechTraining]

Thanks Alex! That's a great question...a dueling of the sensors! Battle royale inside the motor. Well, I think that depends on the vehicle. In my experience, a MAF car will preference the MAF over MAP for air/load calculation. Also, we should factor in throttle and or accelerator pedal position right? In theory, a MAF and Map sensor with the EGR open would see less grams/sec on the MAF, and Map would read lower pressure. But...I think at that point the computer would take a peak at the TP and APP and see if you're in the throttle at all. So trust the MAF and O2 for fuel correction at that point, because the MAP seems to be lying based on TP ans APP right? Again, like I said in the video it's a case by case thing. Different volumes of EGR gas flow could really throw this for a loop...or where that EGR is piped into the motor....so many variables...so little time! Great follow up question Alex!!! What are your thoughts on how this would react? Mike Becker, Technical Services Instructor

[@NickStokes69]

Car is running sluggish and rich. I have had the egr replaced twice and it actually became more sluggish so much so it shut down. Help!!! I haven’t cked the mas yet

[@masonp870]

A stuck open Egr does make the car run too lean because what it does is circulates gas into the intake that cannot burn like co2 so the co2 to oxygen ratio is off when your burning in 100% oxygen it burns hotter than a 70/30 oxygen to co2 ratio so you will burn hotter because you are receiving too much combustible air.

[@kdeh21803]

I'm chasing a stubborn P0507 Code on a '05 Grand Prix Series 3- 3800 Non-Supercharged. I also have a LTFT of 25 and a STFT of 16 at idle. Which usually means a vacuum leak... I've smoked the engine... I see no leaks..... I've switch out the TB and the MAF with one known to be good. I've replaced the PCV and it's gaskets. The Intake manifold gaskets have been replaced recently. All the "usual" things regarding this code I have done..... I just can't seem to find the cause............................other ideas, that why I'm watching this EGR video......?? BTW.... the engine seems to run fine... until the CEL comes on and it goes into Limp Home Mode.

[@GoTechTraining]

Hey, that's running super lean. You could be dealing with a fueling issue. Is your pressure in spec? Mike Becker, Senior Technical Instructor

[@kdeh21803]

@@GoTechTraining I found the issue, (finally)..... the brake booster had a leak.... when I pulled the hose and plugged it.... the fuel trims returned to normal.

[@jamesdemoure2215]

I have a 2000 ford f150 i have the codes p0171 p0174. And i cant find any vac leaks. Was running fine driving down the road and all the sudden its start to shake the truck..fuel trims at 25 for ltft and stft was also around 20 bank 1 seems worse then bank 2..and ideas?

[@Carlostype]

Nicely explained, thanks!

[@GoTechTraining]

Thanks Typey1! Mike Becker, Technical Services Instructor

[@ThunderbirdRocket]

Fantastic tutorial ! Thanks !!

[@gilbertnickerson1512]

hey great class on 02 sensors. i would like to know more about the PCM . how does the input cause an output voltage control the fuel injector. if knew that then i would not think of the o2 as switching. more like biasing a transistor to cause the transistor to apply current to keep the fuel injector open longer or shorter , more fuel or less fuel to cause the mixture of fuel and air to have more 02 or less 02 after burnt . then it would make more sense as to why the mark point of 430 Mill volts, is important. if the output of the 02 goes above or below the set point then that causes a transistor to turn on longer or shorter . to apply voltage to the injector to apply fuel. i am assuming the set point is the optimum fuel air mixture.

[@GoTechTraining]

Gilbert, if only it were that simple. The 02 sensor is kinda like the transistor analogy, but it does not DIRECTLY feed the pulse width modulation of the fuel injector control. There are way more variables involved in injector control besides just the 02's. IAT, ECT, Load, etc are all examples of things that affect it. The 02 sensor drives the fuel trims. Fuel trims are adaptations to the base program for the injectors. Cars are ever variable. Mike Becker, Senior Technical Instructor

[@alanjm1234]

What happens when an EGR valve sticks closed?

[@jacobwilliamsjr3225]

It helps a lot!! Thanks!

[@GoTechTraining]

Thanks for watching Jacob! Mike Becker, Technical Services Instructor

[@miguelmunoz2207]

Me gustaría que este video estuviera en la versión español. gracias

[@depressorfull]

"I think it's going to be a great uh," (in a low, gravelly, creepy voice)-->, "to *_never_* screw up again." "It'll be a great little lesson for this episode of TechConnect". lol.. jk.

[@baxrok2.]

Great info and clarification. Nice to see that Mazda intake on the bench. Thanks!

[@GoTechTraining]

Thanks Baxrok2! I love throwing some visuals in there...besides that intake was just toooo much fun to cut apart to never use it again. Did you catch the class I used it in? We were talking about the IMRC system on a (I believe) 04' Focus with the 2.3L. Mike Becker, Technical Services Instructor

[@baxrok2.]

I should have said, it was nice seeing that MazFord 2.3L intake manifold on the bench! Yes, I watched that IMRC video with great interest since at the time I had been struggling to find useful info on operation. Very creative and effective use of the liquids to show EGR gas displacing oxygen. Keep up the great work Mike!

[@GoTechTraining]

THanks! A little visual goes a long way! Seeing is believing right? Mike Becker, Technical Services Instructor

[@cru551010]

Nice job!!!!!! 👍👍👍

[@GoTechTraining]

Thanks Cruz SJ! Mike Becker, Technical Services Instructor

[@bmwe657er]

If egr valve stays permanently close is like you are blessed, isn't it?

[@GoTechTraining]

Hey Arnold, sure, if you don't mind the check engine light being stuck on! Mike Becker, Senior Instructor

[@bmwe657er]

@@GoTechTraining is it enough to remap it so the valve stays closed, or I need to blank it as well? I am considering an egr off...

[@GoTechTraining]

Depends on the vehicle. I'm sure if you remap it and force the ECM to never run the test it could never fail...it would just never pass either. Which may inhibit the vehicle from passing emissions. Mike Becker, Senior Instructor

[@clutch5sp989]

WTF...don't men shave anymore?

[@joshuagibson2520]

I shave once a month. When time permits.

[@K24NA]

For thousands of years men no shave