Did any of you had a bad evap purge valve? Or egr valve witch i think is the same?! Symptoms? Apparently its a common proplem on cars. Would like to have more information on this. Thanks!
Evap purge valve goig bad?
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EGR and EVAP are two completely different systems.
EGR lets exhaust gas recirculate into the engine.
EVAP systems make the vapors from the fuel tank be contained and admitted to the engine to burn in a controlled way.
EGR=exhaust gas recirculation
EVAP = evaporation - evaporative control
EGR lets exhaust gas recirculate into the engine.
EVAP systems make the vapors from the fuel tank be contained and admitted to the engine to burn in a controlled way.
EGR=exhaust gas recirculation
EVAP = evaporation - evaporative control
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Originally Posted By: 2008wrx
Pull code! Check engine light?
yes i got the code for that before, but the stupid dealer never changed it. There was some pressure somewhere, hesitation on long trip on highway only, on steady rpm. I would pass a car and the car would sudently jerk, and than would be fine.
Pull code! Check engine light?
yes i got the code for that before, but the stupid dealer never changed it. There was some pressure somewhere, hesitation on long trip on highway only, on steady rpm. I would pass a car and the car would sudently jerk, and than would be fine.
Its been couple months now. I dont know the exact code, i mostly do short trips actualy. I was wondering if this was the cause of the jerk on highway.
Yes they are diffrent, but is it possible my ca dont have a egr valve?
I have no code of light for a missfire. But i upulled out the spark plug and theres one darker, carbon deposite, black around the tip. Is this a sign?
I would like to offer more help! But i am not sure n i dont want to talk like an idiot. Let someone else chime in later today. Actually i experienced a bad EGR before; EGR stuck opened after warm cruise; so i had a rough and bad idle. Back in the days; there were no "check engine" system. I think if you want to DIY, i would do one thing at a time, start from the cheapest. I would change the spark plugs first (how old)? Then i might try a bottle of Techcro Concentrate since there is no Code involved.
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I got new plugs, but since you just said that, when it rain outside, the car have a rough idle, not shaky, my more rough than usual, i think I should test my coil pack with water spay.
Originally Posted By: wolf_06
I got new plugs, but since you just said that, when it rain outside, the car have a rough idle, not shaky, my more rough than usual, i think I should test my coil pack with water spay.
Good idea. sounds like 'spark" related. I dont like "testing" parts to diagnoise problems LOL! Also when you pull out the coil pack; see the tube that connect to the spark plugs have any "carbon" tracking and the spark acutally ground to the wall instead of to the plugs. Usually they they greyish color.
Try a bottle of 'Fuel Injection" cleaner from Techron.
I got new plugs, but since you just said that, when it rain outside, the car have a rough idle, not shaky, my more rough than usual, i think I should test my coil pack with water spay.
Good idea. sounds like 'spark" related. I dont like "testing" parts to diagnoise problems LOL! Also when you pull out the coil pack; see the tube that connect to the spark plugs have any "carbon" tracking and the spark acutally ground to the wall instead of to the plugs. Usually they they greyish color.
Try a bottle of 'Fuel Injection" cleaner from Techron.
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I tried many fuel injectors cleaners, none help really..m
an evap purge valve going bad is when they leak and let fuel vapor from the tank into the manifold and it causes a lean condition when not expected. they generally don't stick completely open where it's a vacuum leak and you feel it. It happens at random time and generally throws a lean condition on one or both cylinder banks and you don't notice anything but the check engine light coming on. the amount of extra air it lets in is minimal so the engine runs fine but the oxygen sensors catch it.
the same can be for the AIR system which injects air into the exhaust system at startup to hep catalytic converters warm up faster. that solenoid valve can do the same thing.
an EGR on the other hand generally causes the engine to run poorly, you feel that, and it sets lean condition codes. All 3 are common unfortunately so you need a scan tool that will record data over a period of time to diagnose stuff like this.
the same can be for the AIR system which injects air into the exhaust system at startup to hep catalytic converters warm up faster. that solenoid valve can do the same thing.
an EGR on the other hand generally causes the engine to run poorly, you feel that, and it sets lean condition codes. All 3 are common unfortunately so you need a scan tool that will record data over a period of time to diagnose stuff like this.
Originally Posted By: 1 FMF
an evap purge valve going bad is when they leak and let fuel vapor from the tank into the manifold and it causes a lean condition when not expected. they generally don't stick completely open where it's a vacuum leak and you feel it. It happens at random time and generally throws a lean condition on one or both cylinder banks and you don't notice anything but the check engine light coming on. the amount of extra air it lets in is minimal so the engine runs fine but the oxygen sensors catch it.
the same can be for the AIR system which injects air into the exhaust system at startup to hep catalytic converters warm up faster. that solenoid valve can do the same thing.
an EGR on the other hand generally causes the engine to run poorly, you feel that, and it sets lean condition codes. All 3 are common unfortunately so you need a scan tool that will record data over a period of time to diagnose stuff like this.
Can a defective purge valve make such a big difference? If EVAP is malfunction and he has a 2008 car, would that trigger CEL?
an evap purge valve going bad is when they leak and let fuel vapor from the tank into the manifold and it causes a lean condition when not expected. they generally don't stick completely open where it's a vacuum leak and you feel it. It happens at random time and generally throws a lean condition on one or both cylinder banks and you don't notice anything but the check engine light coming on. the amount of extra air it lets in is minimal so the engine runs fine but the oxygen sensors catch it.
the same can be for the AIR system which injects air into the exhaust system at startup to hep catalytic converters warm up faster. that solenoid valve can do the same thing.
an EGR on the other hand generally causes the engine to run poorly, you feel that, and it sets lean condition codes. All 3 are common unfortunately so you need a scan tool that will record data over a period of time to diagnose stuff like this.
Can a defective purge valve make such a big difference? If EVAP is malfunction and he has a 2008 car, would that trigger CEL?
About two years ago my truck's "check fuel cap" light came on and it threw a code for an EVAP leak. I could smell gas around the truck, but it was running fine. After looking the system over for damage, I found a tiny vacuum line going to the purge valve had worked loose. I plugged it back up and the light went away. Check for something simple like this before throwing money at it.
I just changed it on my truck, pull the code I think mine was a P0449 off the top of my head.
Other than the code and the CE light their are no symptoms since its an unimportant part. If you don't have to take your car threw emissions and the CE doesn't bother you, you can ignore it forever.
Other than the code and the CE light their are no symptoms since its an unimportant part. If you don't have to take your car threw emissions and the CE doesn't bother you, you can ignore it forever.
I have had to replace my evap valve. In my case it was a code 0455. didn't notice any driveability issues, but the CEL was on for about 40K miles before I fixed it.
Bad EGR may make the engine run better or worse, depending on how it is broken/faulty.
A bad EVAP system will do the same - it can go either way. Induce a vacuum leak, not purge, purge too often, etc.
A bad EVAP system will do the same - it can go either way. Induce a vacuum leak, not purge, purge too often, etc.
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