Running lean after airaid intake
Thread Starter
Burning Brakes
Joined: Dec 2014
Posts: 959
Likes: 24
From: Los Angeles, CA
So I'm about 85 miles. No CEL yet. I do feel my car idling slightly rougher. Like it shakes a little more than before.. But I am not too sure about that. My RPM needle has a slight play in it too. Like it won't idle and stay steady.. It goes up and down a little bit.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Whenever adding a CAI you are increasing the amount of airflow----
The ECM compensates for this at P/T by ADDING fuel via your fuel trims-- Typically fuel trims will eventually "learn out" and settle on"0" after about 50-75 miles of normal driving---However IF your fuel trims are beyond approx. 20% the fuel trims may never quite learn out correctly---If they stay beyond 20% too long you'll eventually get either a rich or lean code----
Until they learn out what you end up with is an engine that is lean at P/T and rich at WOT----It is imperative to data log your fuel trims to see where they are at--Most likely they are positive----
Even most scanners have the ability to read fuel trims in real time-- You need to see where they are at and see IF they have learned out--
Trims that are far off will make your car idle rough--
Ultimately a "real tune" would immediately correct this issue---and well worth the $$$$
Cheap CAI's only add a small amount of airflow---adn normally learn out quickly
But better ones such as Air-Aid and Varraram increase airflow so much that they need a tune---- But to me that's good news !!! as after the tune---You're gonna make some awesome HP----
The ECM compensates for this at P/T by ADDING fuel via your fuel trims-- Typically fuel trims will eventually "learn out" and settle on"0" after about 50-75 miles of normal driving---However IF your fuel trims are beyond approx. 20% the fuel trims may never quite learn out correctly---If they stay beyond 20% too long you'll eventually get either a rich or lean code----
Until they learn out what you end up with is an engine that is lean at P/T and rich at WOT----It is imperative to data log your fuel trims to see where they are at--Most likely they are positive----
Even most scanners have the ability to read fuel trims in real time-- You need to see where they are at and see IF they have learned out--
Trims that are far off will make your car idle rough--
Ultimately a "real tune" would immediately correct this issue---and well worth the $$$$
Cheap CAI's only add a small amount of airflow---adn normally learn out quickly
But better ones such as Air-Aid and Varraram increase airflow so much that they need a tune---- But to me that's good news !!! as after the tune---You're gonna make some awesome HP----
Platinum Supporting Vendor
Joined: Sep 2001
Posts: 3,665
Likes: 341
You have a vacuum leak. If the intake was flowing allot more air you would more than likely get a reduced power since the MAF g/sec and the calculated g/sec would be way off. When you see a 0171 and 0174 code you have a vac leak after the MAF.
Melting Slicks
Joined: Sep 2008
Posts: 2,360
Likes: 59
From: San Jose California
This was not due to the increased air flow, but the turbulence across the maf.
But, I have not heard of this issue with the air raid intake. Just saying it sounds like a leak, but maybe a very sensitive maf.
DJ
Thread Starter
Burning Brakes
Joined: Dec 2014
Posts: 959
Likes: 24
From: Los Angeles, CA
Alright. Let's break it down. If I had a vacuum leak, wouldnt the CEL reappear by now? 85 miles so far no light? Also, if I had a leak, why did it take over 300 miles for the light to appear? If I have fuel trim issue, why did it take over 300 miles for the light to appear? How long before th light comes back on if I have fuel trim issue?
The first time I double checked and tightened everything again. There was some slack on the rubber coupler. I am worried about the hose that connects to the intake bridge. That nipple could have a leak?
Bottom line, how much longer will it take for the light to come back to see if I have a problem or I don't? I am gonna disconnect the battery and clean my air filter with the cleaning kit and drive for a while during the wknd and see what happens.
The first time I double checked and tightened everything again. There was some slack on the rubber coupler. I am worried about the hose that connects to the intake bridge. That nipple could have a leak?
Bottom line, how much longer will it take for the light to come back to see if I have a problem or I don't? I am gonna disconnect the battery and clean my air filter with the cleaning kit and drive for a while during the wknd and see what happens.
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Platinum Supporting Vendor
Joined: Sep 2001
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Alright. Let's break it down. If I had a vacuum leak, wouldnt the CEL reappear by now? 85 miles so far no light? Also, if I had a leak, why did it take over 300 miles for the light to appear? If I have fuel trim issue, why did it take over 300 miles for the light to appear? How long before th light comes back on if I have fuel trim issue?
The first time I double checked and tightened everything again. There was some slack on the rubber coupler. I am worried about the hose that connects to the intake bridge. That nipple could have a leak?
Bottom line, how much longer will it take for the light to come back to see if I have a problem or I don't? I am gonna disconnect the battery and clean my air filter with the cleaning kit and drive for a while during the wknd and see what happens.
The first time I double checked and tightened everything again. There was some slack on the rubber coupler. I am worried about the hose that connects to the intake bridge. That nipple could have a leak?
Bottom line, how much longer will it take for the light to come back to see if I have a problem or I don't? I am gonna disconnect the battery and clean my air filter with the cleaning kit and drive for a while during the wknd and see what happens.
There is no need to check the trims, you already know they are exceeding 20% because you are getting the code for it. That is what P0171,P0172,P0173,P0174 codes are.
Thread Starter
Burning Brakes
Joined: Dec 2014
Posts: 959
Likes: 24
From: Los Angeles, CA
Let me elaborate some more on this. It doesnt just have to be the intake leaking, ANYTHING behind the MAF. We have seen allot of the pvc tubes cracked and leaking. The best way for you to find your issue is with a EVAP tester. It will smoke the intake and you will find the issue. If the intake was the issue, you could run really rich or super lean which means the diameter of the intake around the MAF is really off. However this should also send the car into reduced power because the meter would actually be reading low and it would not match the g/sec of calculated air, Nor the correct amount of g/sec of air coming through the throttle blade at specific throttle angle. If it is in fact an intake is should be causing lots of issues, unless those were turned off in the cal.
There is no need to check the trims, you already know they are exceeding 20% because you are getting the code for it. That is what P0171,P0172,P0173,P0174 codes are.
There is no need to check the trims, you already know they are exceeding 20% because you are getting the code for it. That is what P0171,P0172,P0173,P0174 codes are.
Should I even be worried about this if the light has not come back??
Thread Starter
Burning Brakes
Joined: Dec 2014
Posts: 959
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From: Los Angeles, CA
Platinum Supporting Vendor
Joined: Sep 2001
Posts: 3,665
Likes: 341
Sorry,
Haven't check back in awhile. The Evap tester you will have to go to someone with. You are already going to get your answer if you are looking at a scanner because you will see huge LTFT, that is why you are getting the light. The only way for a air box to cause this is for the area around the MAF to be way off from the factory unit. The transfer function in your ECU that shows the frequency vs. g/sec is calculated for the diameter of the box around the MAF. If this is different then that table is not correct and you can getreally high LTFT's, positive or negative and when they happens you will get the same codes. Either rich or lean depending. A vac leak will always show lean.
Haven't check back in awhile. The Evap tester you will have to go to someone with. You are already going to get your answer if you are looking at a scanner because you will see huge LTFT, that is why you are getting the light. The only way for a air box to cause this is for the area around the MAF to be way off from the factory unit. The transfer function in your ECU that shows the frequency vs. g/sec is calculated for the diameter of the box around the MAF. If this is different then that table is not correct and you can getreally high LTFT's, positive or negative and when they happens you will get the same codes. Either rich or lean depending. A vac leak will always show lean.
Platinum Supporting Vendor
Joined: Sep 2001
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It can also be the tune since you have that in there. If they have the g/sec way off then the same rule applies that I mentioned above. The first step in fixing this is to one make sure it is not a vac leak, you do not want to fix the tune and then find out you had a vac leak, you just introduced a new problem if you do that. Get the smoke test done, then if it passes go and scan the car and fix the MAF transfer function.
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
0 means it's not having to make any adjustments. It should be oscillating up and down slightly
Values in the+/-5% range I wouldn't really even blink at. Somewhere around 20 or 25% is where you start getting errors.
Values in the+/-5% range I wouldn't really even blink at. Somewhere around 20 or 25% is where you start getting errors.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
From experience I can say that J. Abbott is right. You have or had a vacuum leak.
Tell us how you hooked up your catch can and what kind of catch can it is. If its got a breather on it, your intake is drawing unmetered air from the port behind the throttle body and that's what's causing your lean codes most likely. Or perhaps one of the catch can hoses isn't properly hooked up or even the can isn't screwed tight.
Tell us how you hooked up your catch can and what kind of catch can it is. If its got a breather on it, your intake is drawing unmetered air from the port behind the throttle body and that's what's causing your lean codes most likely. Or perhaps one of the catch can hoses isn't properly hooked up or even the can isn't screwed tight.
Thread Starter
Burning Brakes
Joined: Dec 2014
Posts: 959
Likes: 24
From: Los Angeles, CA
Well.. I have been driving the car for about 400-500 miles now and the lights have not come back. the idle is still slightly rough but I think it was like that before. and the RPM needle still has some play to it but i think this is normal.
Should I still be worried about this.
As for the catch can, it is Elite and I do have a breather attached to the intake tube. The catch can connection are all good to go. I double checked
Should I still be worried about this.
As for the catch can, it is Elite and I do have a breather attached to the intake tube. The catch can connection are all good to go. I double checked
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
Well.. I have been driving the car for about 400-500 miles now and the lights have not come back. the idle is still slightly rough but I think it was like that before. and the RPM needle still has some play to it but i think this is normal.
Should I still be worried about this.
As for the catch can, it is Elite and I do have a breather attached to the intake tube. The catch can connection are all good to go. I double checked
Should I still be worried about this.
As for the catch can, it is Elite and I do have a breather attached to the intake tube. The catch can connection are all good to go. I double checked
https://www.corvetteforum.com/forums/c6-tech-performance/3712523-smoke-from-drysump-breather.html#post1590499693
Thread Starter
Burning Brakes
Joined: Dec 2014
Posts: 959
Likes: 24
From: Los Angeles, CA
OK so we are at it again... After initial CEL was cleared, I drove about 500 miles with no issues. Including all city and highway driving.. Everything was good I thought.
Then I decided to use my intune and change the tune to 91 tune. Then drove the car for approximately 250 and the CEL is back with the same two codes..
This time I checked on the fuel trims... Short term were up and down and mainly at 0 during idle. Long term were like 10 most of the time and st idle.. This is just after clearing the CEL...
Any thoughts?
Then I decided to use my intune and change the tune to 91 tune. Then drove the car for approximately 250 and the CEL is back with the same two codes..
This time I checked on the fuel trims... Short term were up and down and mainly at 0 during idle. Long term were like 10 most of the time and st idle.. This is just after clearing the CEL...
Any thoughts?