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Old 12-21-2009, 12:48 PM
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Dave!
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Default About the EGR valve

A conversation came up in another forum about a car with a failing EGR valve which got me thinking about the EGR valve in the 996 (The one above the alternator connected to the throttle body that loves to click its days away).

Anyway, an EGR valve is one that recirculates exhaust gases into the intake to lower combustion temps and reduce NOx emissions. However, what we call the EGR valve in the 996 is actually called the "Regeneration Valve" at Pelican Parts, and is listed as venting fuel vapors from the gas tank into the throttle body. It is also listed as a "Vent Line" in the parts catalog.

So now I'm just all confused. Anyone more familiar with this valve?

Link to it: http://www.pelicanparts.com/cgi-bin/...1999-05)%20%20
Old 12-21-2009, 12:57 PM
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Originally Posted by Dave!
A conversation came up in another forum about a car with a failing EGR valve which got me thinking about the EGR valve in the 996 (The one above the alternator connected to the throttle body that loves to click its days away).

Anyway, an EGR valve is one that recirculates exhaust gases into the intake to lower combustion temps and reduce NOx emissions. However, what we call the EGR valve in the 996 is actually called the "Regeneration Valve" at Pelican Parts, and is listed as venting fuel vapors from the gas tank into the throttle body. It is also listed as a "Vent Line" in the parts catalog.

So now I'm just all confused. Anyone more familiar with this valve?

Link to it: http://www.pelicanparts.com/cgi-bin/...1999-05)%20%20

And Porsche calls it just what it is: EVAP canister purge valve

It actually pulls from the EVAP canister which breaths in the vapors from the fuel tank.
Old 12-21-2009, 01:10 PM
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Huh. I've always seen it referred to as the EGR so now my world is thrown for a loop. So where is the EGR then? I can't find it in the catalog or for order.
Old 12-21-2009, 01:19 PM
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Originally Posted by Dave!
Huh. I've always seen it referred to as the EGR so now my world is thrown for a loop. So where is the EGR then? I can't find it in the catalog or for order.

You don't have one.
Old 12-21-2009, 01:21 PM
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Well now I just don't know what to think. Thanks for straightening my head out.
Old 12-21-2009, 01:41 PM
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Originally Posted by Dave!
A conversation came up in another forum about a car with a failing EGR valve which got me thinking about the EGR valve in the 996 (The one above the alternator connected to the throttle body that loves to click its days away).

Anyway, an EGR valve is one that recirculates exhaust gases into the intake to lower combustion temps and reduce NOx emissions. However, what we call the EGR valve in the 996 is actually called the "Regeneration Valve" at Pelican Parts, and is listed as venting fuel vapors from the gas tank into the throttle body. It is also listed as a "Vent Line" in the parts catalog.

So now I'm just all confused. Anyone more familiar with this valve?

Link to it: http://www.pelicanparts.com/cgi-bin/...1999-05)%20%20
you are thinking of the secondary injection pump valve? injects fresh air into the exhaust during start up.... this valve is burried by the left plennum. I thought the valve above the alternator is the ram air...
Old 12-21-2009, 03:16 PM
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ERG valves, in my limited experience, are used to pull the vapors from the crankcase and send them back into the intake tract to get combusted, instead of vented to atmosphere.
Old 12-21-2009, 06:07 PM
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WOW!!! We have some confused folks on this one!!! The 996 does not have a EGR valve. EGR stands for exhaust gas recirculation. You will never see exhaust gas in a plastic line/valve too, hello!!! The valve you are looking at is the Tank vent valve, it vents fuel vapors (HC, hydro carbons) from the charcoal canistor into the intake were they are consumed. EGR valves do not pull vapors from the crankcase!!!!!!!!!! They recirculate exhaust gases. You are getting PCV, positive crankcase ventilation and EGR mixed up. The Air oil seperator on the 996 is the PCV system. Maybe some very early 911 had an EGR system, but no 930, 964, 993, 996, 997 etc... ever had one. Thanks to the 3-way catalytic converters on our cars, we do not require an EGR system to reduce NOx. That is all and EGR system is there to do, reduce NOx.
Old 12-21-2009, 06:15 PM
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Originally Posted by porsche52
WOW!!! We have some confused folks on this one!!! The 996 does not have a EGR valve. EGR stands for exhaust gas recirculation. You will never see exhaust gas in a plastic line/valve too, hello!!! The valve you are looking at is the Tank vent valve, it vents fuel vapors (HC, hydro carbons) from the charcoal canistor into the intake were they are consumed. EGR valves do not pull vapors from the crankcase!!!!!!!!!! They recirculate exhaust gases. You are getting PCV, positive crankcase ventilation and EGR mixed up. The Air oil seperator on the 996 is the PCV system. Maybe some very early 911 had an EGR system, but no 930, 964, 993, 996, 997 etc... ever had one. Thanks to the 3-way catalytic converters on our cars, we do not require an EGR system to reduce NOx. That is all and EGR system is there to do, reduce NOx.
Right you are, Ken.
Old 12-21-2009, 07:10 PM
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Yep; PCV vs. ERG - I confused those; thank for the clarification You are demon are techs, right?
Old 12-21-2009, 07:26 PM
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yes sir.



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