Audis Are Confusing - 2008 2.0T

Hey guys! So forgive me, as im very new to this too hah (posted in another thread but definitely should have started my own, like i am now). Ive got a 2008 a4 2.0t and ive been working away at the tune slowly but surely (mainly just working on fuel and boost), and seem to have made some headway if that helps!

Included are the stock tune, my current one, stock log and latest log (note: have done some stuff regarding EGT temps and limits since last log)

Car is M6, CAI (homemade), diverter update/spacer, test pipe, and looking for advice as to what I should be changing in my logging parameters (apparently some of my numbers are extremely off) and just want to get a handle on what some of the pressure map values represent (ex: a pressure ratio of 1.5 makes sense to the ecm but what is "1.5" of exactly lol?)

Any help is sincerely appreciated!!

Did you end up trying out the file I made for you?

Map value should never go below 100KPA as its not a sensor that’s actually located in the manifold

MAF values should be around the 150-190g/sec at wot past 6K

IAT should be around 15-40*C once at operating temp and driving normally

I just finished swapping the values from yours to mine (except for the DTC part, wouldnt show the differences between the files), will take for a test drive/log soon

Unfortunately theres no other sensor to choose from for MAP logging, any suggestions?

MAF ive changed to log sensor 1, will see if that makes a difference

As for IAT, Im in Canada and the temps are already below zero most days and the CAI i made for it definitely gets a lot of that cold air if thats any consolation lol? But yes, I do find it odd that its usually within a degree or so of ambient

EDIT: @TylerJBubbs i see youre in ontario too, guess you already know winter started early here hah

The file I built should have been based on your last file so the changes I made were only applied to the maps required leaving the rest that you modified in place?

Yeah, that's what I thought, but in the comparison list it came up with "Master DTC" difference (again, didn't show what change if any), so I was just going test it now and see if a CEL came on a deal with it from there haha.

I'll post a log soon with the changes from yours

That’s probably where a checksum variation exists, I wouldn’t worry about it

Just use the file I sent you to avoid any discrepancies

Quote:

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Originally Posted by chevelle72

Yeah, that's what I thought, but in the comparison list it came up with "Master DTC" difference (again, didn't show what change if any), so I was just going test it now and see if a CEL came on a deal with it from there haha.

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I think that's a bug in VCM editor. I can compare a file to itself and it'll claim there are DTC differences.

KK, I'll just use yours.. speaking of checksum errors, every once and awhile the car goes into limp mode with an ECM checksum error whenever it has any of these tunes on it. Flash it back to stock, then flash back the tuned file and it's fine again for a bit (has happened like 4 times now over the course of 2 months, so I just always bring my laptop with me)

I'd open a case with HP support on that one. I haven't done a ton of tuning with this system, but have a '12 A4 and a '14 A6 and have flashed both engine ECUs and one transmission ECU multiple times and never had that happen.

This seems to be a running issue on MED9.1 I’ve seen so far, submit a ticket and debug to support when you have issues with a specific file

Yeah, when it first happened upon looking up the DTC code it basically said your ECM was pooched or if you have a tune revert it back to stock, so I guess its fairly common (like a compilation error or something?)

Also, heres the log with Tylers changes to the tune - think i found the right MAF sensor this time, and if im not mistake (though i probably am lol), more boost initially and less by redline?

seems to be alot going here lol mostly it seems to be overboosting and then going way too rich, try this i made some changes


Attachment 94606

This is where it would be really helpful to see requested boost and load lol

So how is it youre determining its overboosting? And that Lambda bias (ECM 14957) Ive noticed before the column values are all over the place and in the latest one you changed a few but its still not in a linear fashion - thats just how these cars work i guess lol?

Yeah, id love to have that for comparison but ive gone through the logging parameters a few times and havnt found anything :(

Must be a glitch, I didn’t touch that param oh no haha

I believe it’s overboosting because our requested load should be around 185-190 at peak and it’s hitting 230 and then going delta fueling for overboost to .72 lambda target

My theory on overboost is because we altered the PR limit the requested boost is passing into cells of our wastegate duty request that were at 95%, so i linearized WGDC request to be more reasonable and left requested load the same

Ive actually found quit a few instances where changing something on one table goes and makes weird changes to other random tables - if you correct the Lambda Bias table so its linear itll go and make changes to something else in fueling but i dont remember which one off the top of my head (didnt commit to the change or test it)

ohhhhhh, see here i thought the higher the load the better lol, so thats why i was asking everything to request that 230 hah. I also thought the low afr was because of the EGTs as it goes far higher than the limits - is there something im missing that indicates its because of overboost?

Ill try the updated tune you sent me and post the log. Is there any other useful parameters i should be logging btw?

Yea that’s the way some of these things work, I wouldn’t worry too much about the random map axis’s that get changed as a result of changes to main maps.

Requested load, requested boost if you can

We also have to be mindful of your HPFP as you have a B7 and we can’t make the boost insnaly high because they don’t have a ton of fuel to go around in stock form