2005 Supercharged A4 Corvette, COS 2 BAR, Speed Density...scaled for 80 lb injectors.

[mowton]

As the title states, having an issue with the attached tune. It has been scaled for 80 lb injectors and running a 2 Bar MAP. Got most of the tune done but when I went to 6000 RPM, experience a severe drop out in Dynamic Air. Tightened belt but MAP (and Boost) were holding? Even stranger, when the PCM "burps" (see 15:53:02 in attached log), subsequent restart result in very rich idle (commanded still good) and she won't take any gas.... bogs, sputters etc. Seems only a complete reflash (2 Bar OS and calibration) will correcte the situation. But the pull after that shows the same "burp" and the cycle repeats. Seems like it is overwriting the PCM or something?????? The is also some timing being pulled at 16:52:59 which I am searching for.

Any help would be appreciated...thanks in advance :)

Ed M

9294

[mowton]

No ideas?

Added info...did find a P0103 (in SD so this is expected) and P0106...we maxed out the table values but I quess we exceded them :) Will kill the test next.

again appreciate any help...

Ed M

[joecar]

Hi Ed, I've been looking at your log file, I see it hick-up, pretty weird, I don't know what caused that... wideband goes to free air for about 0.8s.

[mowton]

Joe,

Thanks for the input. From what I can see, it seems like the PCM reached somekind of limit on its fueling calculations and doubled back someplace? Scaling factor is 65% (65.3 at 80 kPa) for the 80lb injectors and I have been through the tune at least a dozen times trying to find a spot I may have missed :confused:

I am assuming (haven't gotten back to the car yet) that while the APP% is still 100% at the burp, the ETC must not be closing in-line with the injector PW dropping to 6 ms as I thought there would have been a noticable impact to MAP/MAF Freq logs???? Wouldn't it show as a massive blockage and kill the MAF reading and kill the boost?? No fuel at 15 #boost would certainly drive the WB to free air...correct? The only good part is it is so lean, detonation shouldn't be a problem :grin:

As the Dynamic Air and Cyl Air values both have dropped like a rock, another assumption I have arrived at is the PCM has lost its "mind". Doesn't seem like it is related to the injector scaling value though :confused: which really confuses me. Am I over thinking this?

The MAP code (DTC P0106) doesn't force car into Reduced Power, correct? If not then I am not sure if killing that test will have any positive results....Once I cleared the code, it seemed to take gas?

Unfortunately I am leaving on a business trip this am, so I won't be able to get back to the car until Monday but any insight while I am away would be appreciated. I will be on-line and still "working" on this problem.

Ed M

[joecar]

P0106 means that MAP is not as expected for the current operating point... might have to look at the MAP sanity tables under Engine Diagnostics.

[mowton]

After reading a thread in the FI section and comparing this file to one I have on a 2005 TT, I found C0405 at 70C will allow the P0101, P0106 and P0121 tests to run. Will try and set this parameter to 125C when I get back to the shop next week.

Seems like this could be my issue with this project.

Thanks and have a great weekend

Ed M

[joecar]

Good find, let us know how it goes.

[mowton]

That did it :cucumber::cucumber::cucumber: Performing the final "street" tweaks on SD tune and will hit the dyno again this week to dial in the power.

Ed M