Exhaust help needed
Thread Starter
Racer
Joined: Dec 2004
Posts: 455
Likes: 11
From: Clovis CA
Exhaust help needed
I just bought a complete used Stainless Works exhaust system. My EGR on the passenger side is connected to the current headers' third primary, but the new header has the outlet on the fourth primary. What are my options? I really don't need the EGR at all.
Thread Starter
Racer
Joined: Dec 2004
Posts: 455
Likes: 11
From: Clovis CA
Yeah, I said EGR.....I guess it's the air pump. Regardless of what it's called, the tubes that connect to the manifolds or in my case headers. Anyhow, I'm not thinking it's going to line up with the new headers. How do I delete it? The new headers have block off plates already, can I just block off or remove the tubes that would connect to the headers? If so, does it affect the tune??
Le Mans Master
Joined: Sep 2014
Posts: 5,278
Likes: 539
From: Kelowna BC
The AIR pump only operates when the engine is cold for a minute or so. It pumps air into the exhaust to help with cold start emissions. You can remove the system easily.
1) You could simply leave the system running, it'll just pump fresh air into your engine compartment.
2) Better option; remove the entire thing. Some minor weight savings as well. Do a search here, the pump resides by the front DS light, up from the bottom of the car inside a panel.
Whatever you do, if you remove anything ensure you close off the fresh air hose from the air filter box, otherwise your motor will see some dirty air!
1) You could simply leave the system running, it'll just pump fresh air into your engine compartment.
2) Better option; remove the entire thing. Some minor weight savings as well. Do a search here, the pump resides by the front DS light, up from the bottom of the car inside a panel.
Whatever you do, if you remove anything ensure you close off the fresh air hose from the air filter box, otherwise your motor will see some dirty air!
Instructor
Joined: Aug 2003
Posts: 220
Likes: 8
From: A little place called Macungie PA
I'm not against removing the pump but please do a little research. I'm not aware of the tuning code for the C5 corvette but on some other GM models the engine tune plans for the extra air from the air pump in the exhaust stream and makes adjustments to the O2 sensor outputs for engine control. Not saying this is a blocker on the C5's just something to investigate.
Le Mans Master
Joined: Sep 2014
Posts: 5,278
Likes: 539
From: Kelowna BC
I'm not against removing the pump but please do a little research. I'm not aware of the tuning code for the C5 corvette but on some other GM models the engine tune plans for the extra air from the air pump in the exhaust stream and makes adjustments to the O2 sensor outputs for engine control. Not saying this is a blocker on the C5's just something to investigate.
He will need to have the AIR system tuned out or will have messages all the live long day. As for tuning for AIR, it only operates for a minute on start, can't see any need to actually adjust anything, no?
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
The AIR connection changed around model year 2000 so you have the wrong headers for your year of car. No big deal. Either block it off and get a tuner to turn-off the AIR system so it doesn't throw codes or get a new AIR pipe for a later car that matches the header or cut and extend your pipe using high temp silicone hose.
I'm a little confused on your description though because a 98 should have the AIR connected at cylinder #8 and most headers are built for the newer models which put the AIR connection at cylinder #6.
The PCM operates the engine in open loop with the air pump running, just like probably every other newer Chevy on the planet with an air pump. The O2 sensors can only accurately read a stoichiometric air fuel ratio so they can only be used when reading exhaust gas only. The O2 sensors are also inputs to the PCM so the PCM can't simply make adjustments to the O2 sensor signals.
The PCM does check that the O2 sensors read way lean when the AIR pump turns on and will throw a code of that doesn't happen. But, the lack of the air pump doesn't throw off the engine tuning.
I'm a little confused on your description though because a 98 should have the AIR connected at cylinder #8 and most headers are built for the newer models which put the AIR connection at cylinder #6.
I'm not against removing the pump but please do a little research. I'm not aware of the tuning code for the C5 corvette but on some other GM models the engine tune plans for the extra air from the air pump in the exhaust stream and makes adjustments to the O2 sensor outputs for engine control. Not saying this is a blocker on the C5's just something to investigate.
The PCM operates the engine in open loop with the air pump running, just like probably every other newer Chevy on the planet with an air pump. The O2 sensors can only accurately read a stoichiometric air fuel ratio so they can only be used when reading exhaust gas only. The O2 sensors are also inputs to the PCM so the PCM can't simply make adjustments to the O2 sensor signals.
The PCM does check that the O2 sensors read way lean when the AIR pump turns on and will throw a code of that doesn't happen. But, the lack of the air pump doesn't throw off the engine tuning.
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Thread Starter
Racer
Joined: Dec 2004
Posts: 455
Likes: 11
From: Clovis CA
My car is a 99 FRC......the complete system came off of another 99 FRC.
I may very well be being redundant, but I want to make certain I'm understanding properly.
All I need to do is block off my cars air tubes and I won't throw codes or affect the tune. Correct?
I may very well be being redundant, but I want to make certain I'm understanding properly.
All I need to do is block off my cars air tubes and I won't throw codes or affect the tune. Correct?
Thread Starter
Racer
Joined: Dec 2004
Posts: 455
Likes: 11
From: Clovis CA
Oops......okay, just re-read your post. I can block but I need to have the pumped tuned out.
I didn't even think about cutting the pipe and extending it. That seems like the best option.
Thanks!! I really appreciate the input.
One other thing. On the PS header collector, there are two bungs. Before I get under the car and start taking it apart, is my 99 supposed to have two O2's on that side, or do I need to get a pipe plug??
I didn't even think about cutting the pipe and extending it. That seems like the best option.
Thanks!! I really appreciate the input.
One other thing. On the PS header collector, there are two bungs. Before I get under the car and start taking it apart, is my 99 supposed to have two O2's on that side, or do I need to get a pipe plug??