COBB PROTUNED for 11.5 AFR ECU Slowly leaning car out to dangerous AFR???? Help!!!

[KevinD]

one thing to watch out for is boost leaks and vacuum leaks. the two are DIFFERENT, and have different effects on the operation of the car.

first do a boost leak test if you haven't done one (and if all of a sudden your AFRs are swinging wildly, do another). the boost leaks test covers any possible leaks from the compressor cover to the intake valves. any leaks between these two points will cause the car to run rich when your manifold pressure is positive, and lean when maifold pressure is negative. if you have a leak between the MAF and the compressor inlet, then it will cause it to run lean under both positive and negative manifold pressure. there are not a lot of places leaks can happen between the MAF and the compressor, so its pretty easy to inspect.

keep in mind that even a small leak can cause your LTFT and STFT to swing pretty significantly, yet your closed loop operation will still remain within the 14.7AFR target. and as GST and CBRD already mentioned, the trims do effect the open loop operation on the X (this is not the case for the 8/9).

i don't know if i see this as a faulty accessport, i would think that if the car was tuned and worked well for a while and all of a sudden is doing this, i would wager that something else is amiss. if it has been doing it since the day you got tuned, well then it could definately be accessport or tune related.

[Clipse3GT]

Well I think I found the problem. I think it was a pre-turbo problem.

Look at these pictures of the COBB SFI Intake.

Notice the large crack running through the housing, which is open to the other side behind the filter. I am sure that is what is throwing off the LTFT.

I put the stock in take back on with stock filter. I will monitor what happens with the stock intake.

I am shocked. I am calling COBB in a few moments to complain and get a replacement.

[BigT]

Hm, despite the crack, the air entering is still being measured at the sensor.

[Clipse3GT]

Originally Posted by BigT

Hm, despite the crack, the air entering is still being measured at the sensor.

Yes, that is true. But maybe the car is so sensitive that is causing the car to lean out. I will see over the next day or two on how the car behaves. I read that people had issues when the open filter lost its oil and it was dry and the car would change LTFT's. So maybe this was enough for the car to act goofy.

[CBRD]

well, the volume of air could change from when it was tuned, because its allowing un filtered air into the maf, but the maf will still supply fuel for the amount of air it sees...

let meknow what you find out,

ill get ur map converted as soon as i can,

cb

[Clipse3GT]

Originally Posted by CBRD

well, the volume of air could change from when it was tuned, because its allowing un filtered air into the maf, but the maf will still supply fuel for the amount of air it sees...

let meknow what you find out,

ill get ur map converted as soon as i can,

cb

I will see. I put the stock air box on right now, and I recheck all the clamps and readjusted everything pre turbo.

So hopefully it will be the problem.

Thank you Chad for converting my map over, your customer service is second to none.

[Clipse3GT]

Well yet another failure...

LOL...

Here are some DATALOGS from EVOSCAN

LINKS IN POST BELOW

You can see some that in the second log that the last time there is major knock count (36 CA) is where the AFR leans out to 13's. The LTFT and STFT stay within 5%. I like a idiot forgot to monitor boost.

I will try to install my AEM UEGO to be able to datalog with EVOSCAN.

BUT... the only thing now that I can imagine is overboost????????????? Where the boost spikes really hard and the car cannot compensate???

I dunno. I am out of ideas totally now. Changed the intake...still same problem.

Looking over the LTFT over 20 minutes I noticed it went from -4.6% and then after 20 minutes it went to almost -6.1% so I guess it is steadly leaning out somehow.

[GST Motorsports]

Links no workie...

[Clipse3GT]

Originally Posted by GST Motorsports

Links no workie...

Link 1
http://www.mediafire.com/file/myzknm...5_19.18.01.csv

Link 2
http://www.mediafire.com/file/hq5emk...5_19.32.19.csv

Thanks for letting me know.

[GST Motorsports]

What version of Evoscan are you using? I can't tell much from those logs other than your fuel trims are wack.

[Clipse3GT]

Originally Posted by GST Motorsports

What version of Evoscan are you using? I can't tell much from those logs other than your fuel trims are wack.

Evoscan 2.7 BETA5 .

But apparently there were some issues with the BETA5, so I guess there is a new BETA 5 version.


Apparently some got messed up.

EvoScan v2.6 And New EvoScan GPS/Logger/Reflashing Touchscreen Review

Should I revert to version 2.6 of EVOSCAN.

Then select ECU: EVO X

[Clipse3GT]

I wonder if when COBB updated the firmware and asked everyone to update their protune maps with the converter something got screwed royally up.

[flatblackterror]

i see your crack there. But Did you say you pressure tested it? I have to deal with this everyday with the subarus I tune. leak between the maf and the turbo sucking in un metered air causing lean issues. Good luck.

[Clipse3GT]

Well I came back from the dealer for the fuel recall and the AWC campaign, I also switched to a BOSCH relay instead of the POS green and black ones. Right now my fuel trims LTFT are holding steady at negative -.5 etc... for about 30 miles.

Not sure if the dealer flash, the return line, or the BOSCH relay are doing their job. But the logs pretty steady and not jumpy like they used to be.

I will post them up after I log for a little longer and monitor if any changes occur.

[Hiboost]

Keep in mind that if the LTFT's at cruise are "-5.0%" that it is actually running RICH and the car is using fuel trims to remove 5% fuel. This will also be leaning the car out at WOT by 5% which can be a .6 AFR shift (ex 11.5 -> 12.1 AFR).