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Discussion Starter · #1 ·
So I have 2.5 inch equal length headers and up, the stock turbo, and a 3 inch catless tbe. Also a 3 inch cai and perrin turbo inlet on my 04 wrx. Never had any problems till recently. My afr's are suddenly running at 14.7:1 from idle tapering to about 12.8 at 3500 rmps and at about 4000 it drops to 11.1:1 roughly and stays strong there all the way to redline. I have the cobb ap and racetuner (I tune the car myself) and have run logs and everything other than the afr is fine. It trips a system too lean code bank one and suggest a coil wire or plugged injector so I replaced the wires and cleaned the injectors and none of that helped. A friend suggested larger injectors and a new fuel pump and my mechanic/tuner friend suggested 750cc injectors. Do my mods support that much fuel? Would that even it out to a decent 11-11.5:1 after proper tuning? So far we have been unable to tune this problem out and my only other thought is to go back to the stock intake. If that would be better.
 

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You don't need larger injectors with the stock turbo. Could you run 750s? Sure, as long as you tune for it.. but it would be a waste of money unless you're planning on getting a turbo that flows more.


You might try going back to the stock intake if you still have it, but if the tune was working fine with the CAI before I doubt it would be a problem now. Maybe check the voltage on your MAF sensor and make sure it's in the proper range. Clogged fuel filter? I dunno. You're adding fuel to the map and it's not making any difference in your AFRs right?
 

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Discussion Starter · #3 ·
Yes, I tried adding fuel and it didn't help. The really annoying thing is that the cel does not stay on all the time and when it's off it seems to run better. The afr is still at 13.8 to 14.1 range though. Oh and it starting backfiring the last couple of days, when shifting from 2nd to 3rd and occasionally 1st to 2nd at mid range rpms
 

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Is your intake really 3 inch?

Also, the AFR numbers that the AP is returning are completely useless because the stock sensor is not very accurate. You're gonna need to get a wideband O2 sensor if you want something that can actually be used for logging and tuning. If your friend was a good mechanic/tuner he would have known this. Keep him away from your car and keep a good rolled magazine nearby to swat him away whenever he approaches it.
 

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Discussion Starter · #5 ·
Sorry I guess I should have mentioned that in my first post. I have a wideband o2. Those afr's are loffed from my wideband o2.

I also re measured my intake. It's a 3inch and tapers down to 2inch. So where the maf sits is 2inch.
 

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Sorry I guess I should have mentioned that in my first post. I have a wideband o2. Those afr's are loffed from my wideband o2.

I also re measured my intake. It's a 3inch and tapers down to 2inch. So where the maf sits is 2inch.
That's a problem right there. The stock intake is ~65mm. That will throw MAF readings off. What intake is this?
 

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You have any logs to post? With this kind of thing it's often easier to pin down a problem by looking at the logs.

Brfatal is right though, you need to do some MAF rescaling.
 

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Discussion Starter · #8 ·
Yah I do have logs and I'll post them as soon as possible but I don't have the internet hooked up at my new house yet ( just moved and I'm using my phone). So I'll post those as soon as I can.

And not to sound ignorant but I never have done maf rescaling. How do I do that for this intake size?
 

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There are spreadsheets and tools for doing it through romraider, these spreadsheets may be adapted for use with the AccessTuner software I'm sure, but there may be a tool for it for AT or it might be built in for all I know. Sorry, if you were using RR I'd be of more assistance.
 

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Discussion Starter · #11 ·
Do you like romraider or at least opensource tuning better than accesstuner? I know other people who use opensource and love it because of the accessibility and low cost. Would there be an advantage to using it instead of the racetuner? I have thought about switching because it seems very difficult to get help for my year of wrx with racetuner. That and my ap just stopped working on my way home so now I have to send it in on warranty.
 

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Discussion Starter · #14 ·
Alright, thanks for the link and the posts. I'll read through the info and check it out and maybe play around with it before I get my ap back then I'll run some new logs and post them before I make any changes to the map. Thanks for all the help I'll hopefully get the ap back next week and post those new logs.
 

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Discussion Starter · #16 ·
someone else asked that question so I called my dad who purchased it for me (for my b-day a few months ago) and I told him I wanted a perrin or K&N and the one I have has a K&N filter so I didn't ask but he just admitted he bought a generic ebay one and a filter for it. So it's a noname pos ebay cai!

which would you suggest? The K&N typhoon or a perrin? I like the full cai setup as opposed the ram air short intake but for right now I'll go back to stock. I wondered y I had so many problems. I'll put the stock back on and let you know if it fixes the issue.
 

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A 2" ID at the MAF is going to hurt performance. Stock is like 65-66mm. 2" is 50mm. What intake do you have?
he'll definitely have velocity at the 2" neck-down! LOL Just no volume. It's going to be very turbulent at the sensor, which will totally eff with the readings. ask me how I know ;)
 

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Discussion Starter · #19 ·
make it a powdered sugar donut hole and you got yourself a deal!

I had considered turbulence at the beginning of the problem because it explains y my cel isn't always on and my afr's get better to a point when the cel is off. If I have good conistant airflow it doesn't mess anything up other than too much air to fuel and turbulence causes the maf to trip a cel. Hmmm... Ok lol thanks for the help I'll keep ya'll posted.

oh and btw I'm a girl lol I noticed people posting "he" and "his" and not to embarrass anyone just thought I would let you know :)
 

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Ugh. Rogan. My mouth just started watering. No joke.

EDIT: At the donut comment... Not subieQs girl comment... Didn't see she posted that until after my reply. Haha.
 
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