Air Box seal failure???
Thread Starter
Instructor
Joined: Oct 2005
Posts: 164
Likes: 16
From: Lawton Mi
Air Box seal failure???
Have a C7 GS with 6111 miles on it. No modifications at all!! Engine check light on, off to dealer today. Results is a partially clogged catalytic resulting in the engine check light on dash. Blamed on a faulty air box seal, causing dirt into the motor and a failed catalytic. Parts ordered, new airbox, mass flow and catalytics !! Any other C7 owners with similar situation??? Thanks for your time, Greg.
Race Director
Joined: Mar 2001
Posts: 19,910
Likes: 6,703
From: Bonneville Salt Flats
??? You mean a catalytic converter was ruined due to an airbox seal failure??? What in the world would you have been driving through and sucking up? Sounds wonky to me. Maybe an "expert" will chime in, but I'd want a second opinion.
Last edited by Avanti; Jun 5, 2018 at 08:19 PM.
Thread Starter
Instructor
Joined: Oct 2005
Posts: 164
Likes: 16
From: Lawton Mi
Cat inefficiency code popped up on the scanner, thus the "replace it all" verdict!!
Racer
Joined: Oct 2016
Posts: 396
Likes: 72
The filter is on the end of the air intake tube. The airbox not sealing will make ZERO difference. Worst case, your IATs will go up some from hot engine bay air getting in
Intermediate
Joined: Apr 2017
Posts: 42
Likes: 8
Not true. An unsealed airbox would definitely upset fuel trims. More volume available to be inhaled thru the filter. Case in point. Many cold air intakes require proprietary programming to compensate not only for a higher flow filter, but increased volume of available air. Restriction or lack thereof in the intake tract can and does occur before and after the filter
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Racer
Joined: Oct 2016
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Likes: 72
Not true. An unsealed airbox would definitely upset fuel trims. More volume available to be inhaled thru the filter. Case in point. Many cold air intakes require proprietary programming to compensate not only for a higher flow filter, but increased volume of available air. Restriction or lack thereof in the intake tract can and does occur before and after the filter
I seriously doubt fuel trims would be affected enough to run the car at a point rich enough to kill the converters.
And there is nothing proprietary about the programming for an aftermarket intake. its a very simple maf transfer curve adjustment, if any by graphing maf error. And most aftermarket cais will run fine on stock tuning, provided there are not other airflow changing items along with it, ie. long tubes, ported intake manifold, tb etc(which would cause a lean condition, not rich) which kind of throws your leaky airbox theory out the window.
Burning Brakes
Joined: Nov 2013
Posts: 914
Likes: 277
From: St. Petersburg FL
This sounds pretty hokey to me. Which converter(s) are they replacing, right, left or both? Only the primaries have O2 sensors so, if they change them out do they also change out the secondaries at the head of the X-Pipe?
Last edited by DrDyno; Jun 7, 2018 at 02:08 PM.
Intermediate
Joined: Apr 2017
Posts: 42
Likes: 8
I seriously doubt fuel trims would be affected enough to run the car at a point rich enough to kill the converters.
And there is nothing proprietary about the programming for an aftermarket intake. its a very simple maf transfer curve adjustment, if any by graphing maf error. And most aftermarket cais will run fine on stock tuning, provided there are not other airflow changing items along with it, ie. long tubes, ported intake manifold, tb etc(which would cause a lean condition, not rich) which kind of throws your leaky airbox theory out the window.
And there is nothing proprietary about the programming for an aftermarket intake. its a very simple maf transfer curve adjustment, if any by graphing maf error. And most aftermarket cais will run fine on stock tuning, provided there are not other airflow changing items along with it, ie. long tubes, ported intake manifold, tb etc(which would cause a lean condition, not rich) which kind of throws your leaky airbox theory out the window.
Racer
Joined: Oct 2016
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Burning Brakes
Joined: Nov 2013
Posts: 914
Likes: 277
From: St. Petersburg FL
Vararam, which has an open air box advertises "no tune required." So why would a faulty air box seal on a stock air box foul the cats? Now, if the faulty seal was the seal at the base of the filter allowing a lot of unfiltered air past the filter... who knows?
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,475
From: South Florida
Any deviation from the stock OEM airbox, including leaks before the MAF will definitely change the fuel trims. Those of you who are doubting that any deviation from OEM will change fuel trims are making ignorant assumptions.
Last edited by Internets_Ninja; Jun 7, 2018 at 02:40 PM.
Racer
Joined: Oct 2016
Posts: 396
Likes: 72
Just my opinion but the OEM intake setup is drawing air into the filter from the fender area. How would a leak on the box side(ie.. where the box mounts to fender) affect fuel trims. The filter is drawing air in.. it doesn't care where that air comes from. Like I mentioned above worse case if you draw hotter engine bay air into the filter vs only air from the fender.
Le Mans Master
Joined: Oct 2014
Posts: 8,665
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From: Atlanta GA
So even though the MAF is sensing more air , the maf reacts by send in more fuel , all which the motor can use ...because it's the rear O2 that is king by keeping the air to fuel ratio within spec ...
That's why you make more power with less restrictive intake
Not to mention if u are putting that much fuel thru the cat it would smell like hell and the car would be running like crap
Rear cat effecenty code ... probably a bad sensor and they are throwing the parts cannon at it
Dave
Last edited by Dcasole; Jun 9, 2018 at 08:42 AM.
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,475
From: South Florida
Just my opinion but the OEM intake setup is drawing air into the filter from the fender area. How would a leak on the box side(ie.. where the box mounts to fender) affect fuel trims. The filter is drawing air in.. it doesn't care where that air comes from. Like I mentioned above worse case if you draw hotter engine bay air into the filter vs only air from the fender.
Fuel trims reaction to an air leak at the air box will have nothing to do with causing a cat to clog ....really guys .....what is the rear O2 sensor doing down there ... oh that's right monitoring the mixture to keep a 12-13 to one ratio
So even though the MAF is sensing more air , the maf reacts by send in more fuel , all which the motor can use ...because it's the rear O2 that is king by keeping the air to fuel ratio within spec ...
That's why you make more power with less restrictive intake
Not to mention if u are putting that much fuel thru the cat it would smell like hell and the car would be running like crap
Rear cat effecenty code ... probably a bad sensor and they are throwing the parts cannon at it
Dave
So even though the MAF is sensing more air , the maf reacts by send in more fuel , all which the motor can use ...because it's the rear O2 that is king by keeping the air to fuel ratio within spec ...
That's why you make more power with less restrictive intake
Not to mention if u are putting that much fuel thru the cat it would smell like hell and the car would be running like crap
Rear cat effecenty code ... probably a bad sensor and they are throwing the parts cannon at it
Dave