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Thanks for your input C5MSG2004Vert and hubes. I had been waiting for Corsa to get back to me but since they haven't yet, I'll probably reach out to DiabLew to get his .02 on these ideas.
You added the Corsa that adds a lot more air but didn't have the car tuned, so I'm guessing that's the issue. I have Corsa like yours and never an issue (however, it was tuned because they also installed headers and x-pipe).
My intent was to get it tuned with the Corsa intake being the only mod. However, when I sent several data logs over to DiabLew (after letting him know about the Corsa Intake), he replied that the car was running too lean for him to tune and that had to be resolved first. In his defense, even though he knew about the Corsa intake, perhaps he wasn't 100% aware that it was llikely the cause of the 14% or so LTFTs. He provided me with a list of things to inspect to potentially clear up the lean issue so he could do the tune. I plan on clarifying with him that the air intake has been confirmed to be the cause of those lean fuel trims and see what he says from there.
Your 'vette is looking good, Budarooski. Nice and clean!
Originally Posted by C5MSG2004Vert
My 04 was throwing lean codes after a Vararam install with the power duct. The Vararam screws up the air flow and the MAF does not report the correct airflow at low engine speeds. It was not an air leak. Your aftermarket air filter may be causing the same kind of issue. My issue was temporarily fixed by changing the fuel injectorslope to -10 and then increasing the power enrichment +10 with a Trinity handheld tuner. The fuel trims were still high at first like +10, but the PCM corrected it to around 0 and they stayed good. Before that change they were hitting +25 and throwing the codes. Since you have a Diablo tuner you can try making the same kind of change to see if it fixes your issue. There are complete instructions on how to do this on the diablo website. DiabLew should be able to help you with this. The car ran great but I felt it was too lean at part throttle so I just got a $150 tune at ECS. That fixed everything and the car runs great.
Originally Posted by hubes
My thoughts are that if the intake is a slightly different size at the maf, that will mean the car is actually getting a different amount of air than it thinks it's getting. I would expect an aftermarket intake to be slightly bigger to flow a little more and cause this problem. I think it should be easily tuned out. I'm surprised diablew didn't just do that, but I'm sure he knows a lot more about it than I do. Maybe I'm wrong.
Actually, I think I remember seeing a video years ago about the halltech intake where he basically proved that it flows more air by checking ltft before and after installing it
Originally Posted by Budarooski
You added the Corsa that adds a lot more air but didn't have the car tuned, so I'm guessing that's the issue. I have Corsa like yours and never an issue (however, it was tuned because they also installed headers and x-pipe).
Update: After contacting Diablew and letting him know that I ascertained that it was indeed the intake causing the lean fuel trims, he asked me to send him a new steady driving log and he will adjust the airflow/fueling the correct way by "rescaling the MAF sensor table". So in the process of putting the required amount of miles on in order for the ECM to relearn the airflow and settle in and then will be sending away for the custom tune.
Word of advice for anyone who has this air intake - check your fuel trim levels to make sure you don't need a custom tune with this intake!
Update: After contacting Diablew and letting him know that I ascertained that it was indeed the intake causing the lean fuel trims, he asked me to send him a new steady driving log and he will adjust the airflow/fueling the correct way by "rescaling the MAF sensor table". So in the process of putting the required amount of miles on in order for the ECM to relearn the airflow and settle in and then will be sending away for the custom tune.
Word of advice for anyone who has this air intake - check your fuel trim levels to make sure you don't need a custom tune with this intake!
yikes... i am looking into the afe intake and scared to buy any at this point. I have never had these issued with all my other vettes.
