Engine knocking after new air intake - help
Thread Starter
Heel & Toe
Joined: Oct 2004
Posts: 23
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Engine knocking after new air intake - help
I recently replaced the stock air intake with a K & N filter/intake on my otherwise mostly stock 01 coupe. Previously the only mod on the car is Borla cat backs. After driving a couple of hundred miles, the car seems slower and has started knocking during acceleration. What gives?? 
Drifting
Joined: Oct 2003
Posts: 1,540
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From: bloomfield nj
when you say knock,i'm assuming you mean ping.your pcm has gone into "stupid mode",now that you are flowing more air into the motor ,the pcm is now bringing the fuel trims back in,which is the pcm is adding fuel to compensate for the extra air,but it will only fatten it up to a point.your fuel trims[long term] are probably +18-+20[adding fuel to compensate for lean condition]. you can try a pcm reset and idle reset,but the pcm will eventually go back to "stupid mode".
Drifting
Joined: Oct 2003
Posts: 1,540
Likes: 0
From: bloomfield nj
you can go have the car edited [tuned] and have the part throttle fuel parameters tweaked,but to do it for just a air intake would be a waste.install a set of headers[this will help take advantage of you freeing up your air intake]and then get it tuned.
you may want to check your connections after the maf just to make sure you are not sucking in extra air.
you may want to check your connections after the maf just to make sure you are not sucking in extra air.
Last edited by dpd; Nov 25, 2005 at 02:28 PM.
Pro
Joined: Feb 2004
Posts: 534
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From: was Brookline MA but now San Antonio TX
Originally Posted by dpd
you can go have the car edited [tuned] and have the part throttle fuel parameters tweaked,but to do it for just a air intake would be a waste.install a set of headers[this will help take advantage of you freeing up your air intake]and then get it tuned.
Seeing if the car runs better stock isn't a bad idea either.P.S. make sure all maintenance items are up to date! Dirty anything =
and the effect could be magnified by more mods, especailly ones that lean it out i.e. increase airflow.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
TUNE??? Now,,,wait a minute. The only thing that the guy did was install an air filter! I woud have to say the problem is related to something that he did during the install or caused by the install. Most of the time, people fail to get all of the plumbing hooked back up properly and have an air leak!
Like CONNECTICUT stated,
you really need to include what DTC codes are set in the DIC.
If you had too much oil on the filter, it can contaminate the sensors inside the MAF. Get some electrical contact cleaner and wash down the wires and thermsistors inside the MAF. Just dont touch them!!
With the DTC info, we can point you in the correct direction.
Are you sure that you have the intake air fittings between the throttle body and the Mass Air Flow Sensor properly secured and tight, If there is an air leak and it is allowing unmetered air into the engine, it will cause some of the symptoms that you are having. Those connections are CRITICAL!!!
Do you have any MIL (check Engine lights) on??
Here is a link to codes and how to read them:
This is the absolute best C5 Code web site!!!
http://www.corvettedoctor.com/Codes_Page.htm
Once you write down the codes, clear them and thak it for a ride. Check the codes again and post the results of both DTC checks.
Bill C
Like CONNECTICUT stated,
you really need to include what DTC codes are set in the DIC. If you had too much oil on the filter, it can contaminate the sensors inside the MAF. Get some electrical contact cleaner and wash down the wires and thermsistors inside the MAF. Just dont touch them!!
With the DTC info, we can point you in the correct direction.
Are you sure that you have the intake air fittings between the throttle body and the Mass Air Flow Sensor properly secured and tight, If there is an air leak and it is allowing unmetered air into the engine, it will cause some of the symptoms that you are having. Those connections are CRITICAL!!!
Do you have any MIL (check Engine lights) on??
Here is a link to codes and how to read them:
This is the absolute best C5 Code web site!!!
http://www.corvettedoctor.com/Codes_Page.htm
Once you write down the codes, clear them and thak it for a ride. Check the codes again and post the results of both DTC checks.
Bill C
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Drifting
Joined: Jul 2002
Posts: 1,613
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From: Spring Tx
Mine started surging, an idle relearn cured that , Ive changed intakes two or three times since without any problems. also have modified , removed ,reinstalled my hypertech program numerous times with only one glitch due to a low battery.It's quite possible the filter change has nothing to do with your problem, a bad tank of gas could do the same thing!
Thread Starter
Heel & Toe
Joined: Oct 2004
Posts: 23
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I love this place - My level of technical knowledge on my Vette doubles everytime I log on. (Of course, I started at a pretty low level). Anyway, I removed the K & N and sure nuff, some oil had gotten into the MAF. Thanks Connecticut. I cleaned it off, reset the computer and it eliminated the problem. Thanks Bill C for the advice on codes, next time I have a problem I will get the codes before posting the problem.
Race Director
Joined: Dec 2000
Posts: 19,304
Likes: 85
From: San Diego CA
...with a brand new filter???? That's very unusual, to say the least. K&N uses verylittle oil from the factory. Hopefully, you didn't oil it again before you installed it.
Anyway, you did learn a bunch from that exercise!
Anyway, you did learn a bunch from that exercise!
Race Director
Joined: Jul 2005
Posts: 11,308
Likes: 1
From: The Beautiful Greater Bay Area California
Originally Posted by btraer
I love this place - My level of technical knowledge on my Vette doubles everytime I log on. (Of course, I started at a pretty low level). Anyway, I removed the K & N and sure nuff, some oil had gotten into the MAF. Thanks Connecticut. I cleaned it off, reset the computer and it eliminated the problem. Thanks Bill C for the advice on codes, next time I have a problem I will get the codes before posting the problem.
