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Egr Valve

 
Inveigled...Almost.
I love my Chevy Chevette!
Posts: 7
Joined: 09/13
Posted: 09/14/13 12:09 PM

How do I delete it? I have a 91 chevy camaro.  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 09/14/13 07:04 PM

if you disconnect or bypass a computer commanded or vacuum controlled EGR valve on a computer controlled fuel injected motor

you will have a PING at part throttle all the way to full throttle..

you will have a lean spot off idle that may result in a bog off idle...

you will NOT be able to tune these out... even if you have your computer reprogrammed as tuners only generally work in the mid to full throttle areas to make the most horse power and torque..  not at part throttle..


i can explain why it does it.. but it is a lot of typing..

just unplug the EGR if you don't believe me..

take it for a drive plugged in.. then open you hood and unplug it.. go for the same drive.. you will notice a big differences ...

egr flow reduces the percentage of oxygen in the incoming air charge...

atmospheric oxygen has around 21% oxygen..

exhaust steam on a properly running motor has about 13% to 14% oxygen left in it..

so the 21% gets diluted to around 16% oxygen.. just for say...

to make your 14.7 to 1 air fuel ratio.. when the egr valve is flowing properly as commanded.. the incoming air charge has less oxygen so less fuel is needed to support combustion at the proper levels..


but the other side of that coin is..

when you remove the EGR flow. you have more oxygen to burn... so you need more fuel.. your fuel injection is blind during open loop operation... moderate to heavy acceleration..  so it's programmed to know that the EGR is diluting the incoming air charge..  so it will spray less fuel..  the additional oxygen percentage and less fuel is a hotter fire.. causing combustion temps to soar over 2600F causing oxides of nitrogen to form.. NOX..  this lean mixture also causes detonation.. pinging that will destroy your pistons and head gaskets fire rings...

with the EGR plugged in.. and working as designed... you will have a smoother off idle  and moderate acceleration.. also better fuel economy as you don't have to tip deeper in to the throttle ..  

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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 09/14/13 07:07 PM

after you have unplugged the EGR and started the engine with it disconnected.. you will need to clear the codes. by shutting off and disconnecting the battery for at least 30 seconds.. again.. engine off..  

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Inveigled...Almost.
I love my Chevy Chevette!
Posts: 7
Joined: 09/13
Posted: 09/16/13 01:16 PM

Thanks. I'll just leave it on then.  

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