DFCO will not disable on 3 bar upgrade

I currently have a stock 2001 silverado 6.0 lq4 engine and am having trouble disabling DFCO. I had it disabled and was tuning great with everything stock. I then upgraded it to the 3 bar enhancement, added fast 85 lb/hr injectors, and a gm style 3 bar map. I used deatschwerks injector data and changed a couple things but it starts and runs just as good as before. Its still a very rough tune but the huge issue is no matter what i change DFCO wont turn off so I need some advice. I have attached the tune and the log file, thanks.

Attachment 58742
Attachment 58743

You are not in pcm commanded decel mode from what I can see...the IPW are 2.1 (idle settings), the spark is 40 (not being pulled to -10 or so) while the FTC does signifies (low MAP confirms) you are in decel mode but do not see the normal PCM efforts to perfrom DFCO. I do see in idle your WB AFR is like 11.5 which tells me your airflow isn't tuned correctly to start with.

Also the Channels you are logging, do not have required parameters to tune MAF/VE. Based on you only sit in FTC 20,21 1nd 22 you are in open loop so I would tune the MAF and VE first based on your idle values.

Ed M

Okay, I see what your are saying. This system is much more capable then what I learned to tune so i've got a good ways to go but for now I am just running a speed density tune no MAF and will not mess with closed loop for awhile. If I understand you correctly I need to get my idle and airflow straightened out better but I am having trouble understanding why it is running so lean on map values below the idle of around 30. Since DFCO is disabled correctly then what would you recommend to start looking at first because just for the hell of it I increased the low MAP values by like 20% and it had no change so I just assumed DFCO?

Got to a computer and checked out your tune. Need to set DTC p0101=103 to fail on first error. Leave the SES checked so you know it failed over. What 3 Bar mAP? ZR1 (12592525)? If so, map tune values s/b -312.5 and -11.25. Why a 3 bar map on an NA setup? Idle map is 28 kPa which is a bit low. Make sure after you change the Map scalar that with Key on and engine off, and the scanner logging, you read Baro for MAP (101 at sea level and -3 kPa for each 1000ft of elevation). Also the injector data for offset s/b the 0 kPa values copied across the board similar to the IFR for your vacuum referenced fuel regulator.

Get your VE dialed in and work yourself down towards idle.

Add Dynamic Airflow to Channels as this is the only airflow parameter you have without a MAF and commanded AFR. Add both to Chart. Delete the channels you aren't using (i.e O2 mvs, LT/STFT etc). Recommend setting up a Dynamic Cylinder Airmass (g/cyl) Math parameter which is ([dynamic airflow]*15)/[rpm] and use this to reference your timing table and such. Add to Chart and update the two spark Graphs by deleting the MAP axis and add the DCA. Define the WB as a sensor, commanded AFR as a sensor and use the pre-configured AFR error parameter in the MATH predefined so you can chart and graph the error to the VE able RPM and MAP axis values.

When doing street tuning, add the FTC as a filter. As you are in open loop and Gen III, filter out all FTC=22 (decel) data.

Ed M

I really appreciate the help and will work on getting all of it setup with a couple more runs by Monday and post it back up. On to the questions, its an omni power gm based map sensor (12223861). There is way more to this project than I let loose but i'm at the stage of getting everything dialed in before I add boost. It is a 1980 camaro that will have four turbos with meth injection so one stage at a time. Once I get the N/A setup with the new stuff done I will be putting all the turbos and plumbing back on this week.......hopefully lol.

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Originally Posted by Harrisscottharris

I really appreciate the help and will work on getting all of it setup with a couple more runs by Monday and post it back up. On to the questions, its an omni power gm based map sensor (12223861). There is way more to this project than I let loose but i'm at the stage of getting everything dialed in before I add boost. It is a 1980 camaro that will have four turbos with meth injection so one stage at a time. Once I get the N/A setup with the new stuff done I will be putting all the turbos and plumbing back on this week.......hopefully lol.

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No problem, glad to help. Project sounds interesting :cheers:

Ed M

I was able to get the injector values changed and correct calibration from the company for the map sensor. I updated the chart with I think everything you mentioned along with FTC but I got a little lost on the spark graphs and the AFR error parameter so ill have to come back to that. I could only make one quick pass before the rain but could you take another look because its still going terribly lean on decel.

Attachment 58784
Attachment 58785

I think you are way too rich which is reporting lean on decel. Try this VE table and dial it in some...

Ed M