My DFCO doesn't seem to work. My WB hardly shows any differences in AFR when I decelerate. Since I'm using a pretty big cam, can it be that I must raise the DFCO disable MAP Threshold ???

ECM # 16159278 TunerCat DA2 with BLM locked

DFCO enable RPM Threshold 1400
DFCO disable RPM Threshold 1100
DFCO enable MAP Threshold 23 kPa
DFCO disable MAP Threshold 30 kPa
DFCO disable RPM decrease Threshold 125
DFCO enable Coolant Temp. Threshold -30°C
DFCO enable TPS Threshold Hysteresis 0.4
DFCO enable MPH Threshold 30 MPH

 

You need to raise the DFCO Enable MAP threshold and then add the same amount to the disable to keep things working correctly. Your settings. look like the stock settings. I have a mild cam and almost never get down to 23 MAP under normal deceleration. You need to look at a data log during deceleration and see what you actual MAP readings are then set your enable/disable up to how you want the car to behave. As an example, my enable/disable MAP thresholds for DFCO are 33 KPA to enable DFCO (injector PW goes to 0) and 39 KPA to disable it (injectors back on). The MPH and temp settings are OK to leave as is if you are happy with them. Also my OBD1 has an DFCO enable delay timer constant setting. It delays DFCO, the setting on an A4 is 0 sec, but I believe on an M6 it is set to a second or so to prevent neck jerking whenever the throttle is released. Keep that in mind when you look at a trace to see when the injector PW goes to 0.

 

Thanks Bob!!
I looked at me latest uni file and I could see the PW going to "0" at about 39 kPa.
I will try to set enable to 36 and disable to 46 tomorrow and see if it works better than before. I can still raise it to 39 // 49 if I'm not satisfied, what do you think???

BTW, my idle is around 70 kPa at 950--1000 rpm.

Thanks
Arnold

 

You are on the right track, the higher you raise the enable/disable MAP settings the earlier it will cut in. Obviously you don't want to get to the point that you can feel the car surging every time you let off the throttle. It's personal preference, I have tuned my shift points, torque converter lockup, idle and timing characteristics to the way I drive and expect it to behave... that's the fun of custom tuning.
My A4 idle in D is 750 w/about 59 KPA and 850 in N/P w/50 KPA a lot more vacuum than your aggressive setup.

 

I did about an 1/2 hr run this morning and just don't know what to do at the moment. I set enable 36 and disable 46 kPa
DataMaster shows for example:
2500 rpm // 44.3 kPa // 47 mph decel mode goes on. KPa goes down to 34.3 and then starts rising again to 36.6, 38.8 and at
1950 rpm // 40.2 kPa // 45 mph it turns it off.

It's not even 0.5 sec. on!!! I'm raising the points to 39 and 49 and see what happens.

Bob, would you have the time to look at my uni file????

Arnold

 

Sure , either post it up somewhere, or email it. My Id accepts email..

 

Bob, I mailed you the uni file yesterday, it's a little large but I hope you received it nonetheless.

Arnold

 

Bob hasn't had time to answer my mails yet as it seems, so I just wanted to post my results when going to 39/49 kPa without any difference. DECEL mode is on for max 2 seconds, usually only for about 0.5 seconds.
Hope Bob finds the time to get back to me.

 

Thought you wanted to help me by looking at my files??????? Haven't heard from you ever since!!!