LT4 EGR Valve?
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Joined: Apr 2002
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From: East Stroudsburg PA
LT4 EGR Valve?
I recently bought a 96 6sp/lt4 coupe. I had read in many places that the LT4 didn't require an EGR valve.
Today, while checking my PS fluid, I noticed there are pipes tapped to either exhaust manifold that meet at the rear of the intake, go through what looks like a valve - and enter the intake.
If this isn't an EGR valve, can someone tell me what it is?
Today, while checking my PS fluid, I noticed there are pipes tapped to either exhaust manifold that meet at the rear of the intake, go through what looks like a valve - and enter the intake.
If this isn't an EGR valve, can someone tell me what it is?
Melting Slicks
Joined: Jul 2008
Posts: 2,269
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From: Ottawa Ontario
I recently bought a 96 6sp/lt4 coupe. I had read in many places that the LT4 didn't require an EGR valve.
Today, while checking my PS fluid, I noticed there are pipes tapped to either exhaust manifold that meet at the rear of the intake, go through what looks like a valve - and enter the intake.
If this isn't an EGR valve, can someone tell me what it is?
Today, while checking my PS fluid, I noticed there are pipes tapped to either exhaust manifold that meet at the rear of the intake, go through what looks like a valve - and enter the intake.
If this isn't an EGR valve, can someone tell me what it is?
Race Director
Joined: Oct 2005
Posts: 11,770
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From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
I recently bought a 96 6sp/lt4 coupe. I had read in many places that the LT4 didn't require an EGR valve.
Today, while checking my PS fluid, I noticed there are pipes tapped to either exhaust manifold that meet at the rear of the intake, go through what looks like a valve - and enter the intake.
If this isn't an EGR valve, can someone tell me what it is?
Today, while checking my PS fluid, I noticed there are pipes tapped to either exhaust manifold that meet at the rear of the intake, go through what looks like a valve - and enter the intake.
If this isn't an EGR valve, can someone tell me what it is?
Those pipes going into the exhaust manifold and intake are for "air injection"
Thread Starter
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Joined: Apr 2002
Posts: 93
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From: East Stroudsburg PA
Thanks for the responses. My question is answered - but it brings up another one... Why does the air injection plumb to the intake? It seems like it should only go to the exhaust. Please pardon my ignorance - I don't know much about the air injection system.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
GM engineers designed the system that way. GM rarely tells us WHY they do something a certain way. There are probably engineering papers filed away somewhere in the GM archives that explains the "WHY" but we don't have access to them.
We could guess as to the "WHY", but it would be just that, a guess. Don't worry, you'll have enough to keep you occupied with your car so you won't have time to be concerned with the "WHY".
Jake
We could guess as to the "WHY", but it would be just that, a guess. Don't worry, you'll have enough to keep you occupied with your car so you won't have time to be concerned with the "WHY".
Jake
Racer
Joined: Dec 2008
Posts: 271
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From: Lancaster Ca
LT4, No EGR
Along the lines of LT4 not having an EGR valve, I did not know that and have a question. I had an 96 LT1 installed in an 81 corvette. I came across a great deal on LT4 and swapped the engine. When installing, I noticed that the LT4 had block off plates where the EGR should have been installed so I removed the plates and installed the EGR. Car will crank but will not start. I have fuel pressure and spark. Checked injectors with noid light and changed coil. My question is, would the installation of the EGR cause it not to start? I'm going to remove the EGR simply because it doesn't belong but i was wondering is it the cause of not starting. Thanks in advance.
Moderator
Joined: Jul 2005
Posts: 28,812
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From: Parrish FL
St. Jude Donor '06 thru '26
Along the lines of LT4 not having an EGR valve, I did not know that and have a question. I had an 96 LT1 installed in an 81 corvette. I came across a great deal on LT4 and swapped the engine. When installing, I noticed that the LT4 had block off plates where the EGR should have been installed so I removed the plates and installed the EGR. Car will crank but will not start. I have fuel pressure and spark. Checked injectors with noid light and changed coil. My question is, would the installation of the EGR cause it not to start? I'm going to remove the EGR simply because it doesn't belong but i was wondering is it the cause of not starting. Thanks in advance.
