Rough Idle AFTER CAI Mod
Thread Starter
Racer
Joined: Jun 2013
Posts: 435
Likes: 41
From: Troy Ohio
Rough Idle AFTER CAI Mod
Just completed my install of a new Halltech Venom II Air Induction System. This was supposed to be just a "swap" with the stock system on my '04 CE Coupe - completely stock LS1 motor. Prior to the swap, engine ran so smooth you barely knew it was running. Upon startup AFTER the Halltech unit was installed, car started right up, but ran very rough at idle. Let car idle for a couple of minutes and noticed "check engine light" came on very breifly, but went out. Shutoff the engine and pulled any codes off DIC. Had a PO300 - Engine Misfire code. Could this be, in some way, related to the CAI mod that I recently did? Any thoughts or ideas from the experts on the Forum would be appreciated. Should also add that engine only has 18,300 miles on it, just about new. Thank you.
Last edited by candyredwing; Mar 14, 2015 at 09:24 AM. Reason: To add more info.
Le Mans Master
Joined: Feb 2012
Posts: 6,644
Likes: 479
From: OK
I would first double check my install...
then the first question, is the MAF staying in the factory location or moved?
I know with the Vararam they suggest at start up you go for about a hour long cruz just taking it easy letting the computer adjust to the new air, so it can make it's own adjustments to not run rich...
then the first question, is the MAF staying in the factory location or moved?
I know with the Vararam they suggest at start up you go for about a hour long cruz just taking it easy letting the computer adjust to the new air, so it can make it's own adjustments to not run rich...
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
I would first double check my install...
then the first question, is the MAF staying in the factory location or moved?
I know with the Vararam they suggest at start up you go for about a hour long cruz just taking it easy letting the computer adjust to the new air, so it can make it's own adjustments to not run rich...
then the first question, is the MAF staying in the factory location or moved?
I know with the Vararam they suggest at start up you go for about a hour long cruz just taking it easy letting the computer adjust to the new air, so it can make it's own adjustments to not run rich...
Make 100% sure that you have a proper seal at ALL the joints between the MAF and the Throttle Body.Any leaks or UN-METERED air will cause issues like this.
Bill
Thread Starter
Racer
Joined: Jun 2013
Posts: 435
Likes: 41
From: Troy Ohio
MAF was relocated, per the Halltech instructions, from the stock location to just before the Throttle Body. Ihave double checked all the connections and they appear to be tight and sealed.
Le Mans Master
Joined: Feb 2012
Posts: 6,644
Likes: 479
From: OK
I think I'd still go for a nice long easy cruz and see if that helps.
Last edited by 73Corvette; Mar 14, 2015 at 10:40 AM.
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
You may need to add a screen for the MAF, I think the Z06 is not screened OEM and when you relocate the MAF and the CAI it creates too much turbulence. Thus the need for the screen to eliminate said turbulence.
I think I'd still go for a nice long easy cruz and see if that helps.
I think I'd still go for a nice long easy cruz and see if that helps.
100% on BOTH recommendations. The MAF air flow is calibrated to the FACRORY MAF location. Moving it can and will create issues. Sometimes, the PCM can adjust for them,, sometimes it cant.If you dont have a MAF screen,, Just adding one may resolve your issue.
Sometimes,, if you like your set up, you will have too have someone recalibrate the MAF Calibration to perform in its current location.
\
See if you can find someone to read your Long Term Fuel Trims. That will tell you how hosed your tune /MAF cal really is.
If you have a scanner that reads live sensor data,, you can do it..Bill
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Thread Starter
Racer
Joined: Jun 2013
Posts: 435
Likes: 41
From: Troy Ohio
Just an update - this is a Coupe, not the Z06. The stock MAF DOES HAVE a screen. I double checked the alignment with the Throttle Body and seems to be OK. Thanks for the feedback so far.
Le Mans Master
Joined: Feb 2012
Posts: 6,644
Likes: 479
From: OK
OK.. still moving the MAF can cause some issues... drive it and report back. If the MAF location is the problem you might put it back in the stock position and see if that helps or you may have to get a tune.
Thread Starter
Racer
Joined: Jun 2013
Posts: 435
Likes: 41
From: Troy Ohio
Wish I could test drive it, but seats are out of the car being recovered plus there's still a lot of winter salt on the roads. Will give you an update in a couple of weeks (hopefully) when the seats are back in.
