Throttle Cracker Tuning Question {B4309}

[pinstripebob]

I don't have an issue changing my MAF sensor. I do have a Delphi part number 25168491 black 85mm MAF I can put in, I have the adapter harness for it as well. We should be able to use it with the MAF curve out of an 2001 Suburban with the 5.3 right?

If I make that hardware change, I have a set of D585 coils I'd like to put on as well. I've been putting off installing both parts, so this may be a good break to put them on. These should need the spark dwell table out of a Yukon with the gen. III 6.0.

In the interim, I'll flash your Mod5 tune and get a log. Is it still helpful when I list portions of the tune with/without bucking?

[statesman]

Yes, listing where it's bucking is still helpful... but make ALL the hardware changes you want to make now, then do a log for me. Use the 2001 Suburban MAF curve, even if it shows lots of trims (as long as it doesn't peg the trims) and use the Yukon spark dwell table for the new coils. Just apply those changes to the Mod5 tune and remember not to drive on the Mod4 tune anymore.

[statesman]

When you post your next log, also post the tune file with all the changes you made.

[pinstripebob]

Got it! I ran back through my log, it goes wicked lean in PE with Mod4! I'll get this flashed before I go for another drive.

I'll post the tune with the log as well. I try to keep a tune history in my comments, with each of your Mods I've transferred your changed tables and written the changes in my history. Helps me keep track of things.

[joecar]

Write long post separately in Nodepad first, then paste to reply.

I've been out of town for a few days, I'm slowly catching up.

[pinstripebob]

Alright I made the changes, did some logging and updated my MAF table. Overall I'm pretty pleased with the results, the car seems to turn on better and drive more smoothly. The MAF table looks like a normal MAF table, too. I Included your Mod5 updates, Statesman, updated the spark dwell table for the D585 coils, and got the MAF table in a pretty good spot. I still have bucking below 1200RPM off throttle, and sometimes at low throttle inputs. I've included the updated tune and the latest log. Below are some roadmap notes for the tune. ECT hits 80C around frame 1290, have a look at IATs for a laugh.

Steady throttle crusing:
Frames 1325-1679
Frames 3321-3707

High throttle acceleration:
Frames 1801-1892

Bucking with throttle input:
Frames 2420-2607
Frames 3834-3867
Frames 4575-4630
Frames 4954-5217
Frames 7586-7686 (pretty bad here)

Bucking during deceleration:
Frames 1917-2139
Frames 2316-2360
Frames 4642-4714
Frames 6738-6769
Frames 10,405-10,465

Let me know what you think, replacing the MAF sensor seemed like a good call, I'm glad I had that Delphi unit sitting around.

Tune:
Garrett_GTO_tuned_20190125_2.ctz

Log:
GTO Jan 30 2019 IBC to home.efi

[statesman]

I just had a quick look at your log and yeah, your IATs are impressive. I also noticed your engine take a dump towards the end of the log... I'll have to take a closer look at what happened there. I don't have the time right now to run your numbers, but I 'll try to have something for you this weekend.

[pinstripebob]

Yep sounds good! Are you seeing the dump around frame 13,400? It does that periodically, especially with the headlights on. That should have been when I pulled into my driveway and garage. It does that in low speed situations like parking lots occasionally.

[statesman]

Let me know what you think, replacing the MAF sensor seemed like a good call, I'm glad I had that Delphi unit sitting around.

Yeah, this Delphi unit is performing much better. Your fueling already looks reasonable, but I need it a bit closer.

When you flash in this update, I'd like you to also clear your trims.

[pinstripebob]

This last week has been really busy for me, but I flashed your Mod6 and got a good log. I made sure to get up to operating temp, reset the fuel trims, then start the log and start driving. Overall the car is noticeably better under low RPM/low TPS driving, definitely less bucking. It does a better job under "parking lot" conditions, RPM doesn't drop and swing as much.

There was something weird, AFR went lean for a bit. It seemed to go lean after a higher TPS/RPM pull around frame 2,550, very odd. Restarting the engine/widebanad seemed to fix the wideband's readings though.

ECT for the log hits 80C around frame 440. Below are the trouble spots I noticed:

Low TPS bucking:
Frames 1,078-1,126
Frames 1,330-1,368
Frames 2,048-2,080
Frames 3,079-3,321
Frames 4,432-4,525
Frames 4,815-4,875
Frames 4,918-4,973
Frames 5,263-5,395 (pretty bad here)
Frames 5,621-5,717 (bad here as well)
Frames 9,661-9.721
Frames 10,223-10,247

Bucking while decelerating:
Frames 1,729-1,751
Frames 2,180-2,202
Frames 3,480-3,507
Frames 8,332-8,349
Frames 8,373-8,384
Frames 8,456-8,481
Frames 8,863-8,907
Frames 8,951-8,993
Frames 10,254-10,277
Frames 10,966-11,007 (bucking got worse as it dropped RPM)

Let me know what you think. Again, I appreciate the help, thank you!

Log:
GTO Feb 7 2019 IBC to home.efi