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Eliminating KR - I think I see the problem?

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digitaloutsider

New member
Hey guys, not new to these cars at all, but definitely new to tuning. The last L67 car I played with at all was my '98 GS years ago (3.4" pulley, headers, 3.29s, etc), and it was just a car I got very lucky with: the DHP 1.5 BIN worked flawlessly on that car and I never saw anything beyond tiny blips of KR on hot days and, as far as I know, that car still runs great for the current owner.

Now I'm back with another car, an '01 GS, and I'm getting my feet wet into modding again. Last weekend I did a Gen V swap, along with some other stuff. So for now the mod list is:


  • 3.6" pulley on Gen V
  • Front and rear Powerlogs
  • 3" downpipe
  • 3" catback
  • Intake
  • AL104s

I'm noticing that I'm getting some sustained KR near the end of each gear, along with some blips here and there. At first, I attributed it to the DHP tune, so I went back to stock and started over. Generally, the KR doesn't exceed ~2.8 degrees or so, but on a recent scan I did see one blip of 4.2 degrees which really scared me. I started going through Jerry's Tuning Notebook as a guide and wasted a lot of time on a VE tune until I got back on here and read again that it's probably not worth it. So I did some scans and used Eddie's table tool to try and clean up the MAF tune a couple of times, but to no real difference. As of now, the PCM is stock minus the changes that Jerry suggested for torque management, shifts, etc along with the MAF and VE tables slightly tweaked. I have included the BIN file currently on the car.

Looking at the scans, it seems that my O2 readings are below where they should be, only in the high 800s. This would indicate I'm leaning out, right? Is this too aggressive of spark advance or simply not providing enough fuel? I'm seeing positive LTFTs so I'd think it's too lean in the tune..

I REALLY wish I would have had a more recent scan of the car unmodded, but the last time I scanned it was probably in May '16 when I got an AVT box and dumped DHP 1.5 on it. It had no appreciable KR then, but that was also with good summer fuel down in GA, not to mention being totally stock, right down to the U-bend. I don't know if a combination of the terrible winter-grade 93 octane and the ~55 degree weather is making matters worse here.

I'm in the middle of reading through webracin's tuning guide that Scotty linked to in another thread, there's just a lot to take in right off the hop.

Scan 1: http://superchargedv6.com/tuning/9Mar2017-Scan1.csv
Scan 2: http://superchargedv6.com/tuning/9Mar2017-Scan2.csv
BIN: http://superchargedv6.com/tuning/MAFTune2.bin
 
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did you do the cat kill in tiny tuner? that could be hurting ya.

whats your wot timing set at in the bin? might have to pull it back some, when you have kr thats not going away the maf and the o2 readings become off.
 
Scottydoggs said:
did you do the cat kill in tiny tuner? that could be hurting ya.

whats your wot timing set at in the bin? might have to pull it back some, when you have kr thats not going away the maf and the o2 readings become off.
Click to expand...

The rear O2 is still in since I got the catted DP, so I didn't mess with the cat diagnostics. I'll check the BIN when I get home, thanks for giving me a place to start!

As for a wideband, I want one, but I've heard a lot of grief about deleting the rear O2 in the 01+ cars. I guess I can try to find another spot to get a bung welded in at.
 
what down pipe you get? if its got a hi flow cat you need to delete the rear o2 from the bin, and then delete its codes and the cat code.
 


Here is the Good Fuel Spark table:

hogfs.png


It's my understanding that it will command whatever is in the GFS table + the AFR Spark Modifier table, so here are those settings:

afrsparkmodifier.png


Scottydoggs said:
what down pipe you get? if its got a hi flow cat you need to delete the rear o2 from the bin, and then delete its codes and the cat code.
Click to expand...

It's the ZZP catted downpipe, which they advertise as: "The downpipes we sell come with a high performance converter. It is OBD2 compliant but it is on the very edge of being so." Take that for what you will.

If that could be part of the issue, I'll go ahead and remove all the rear O2 stuff. I've read that the cat diagnostics can throw the LTFTs all wonky, and now that I think about it, I do see really high LTFTs on extended decel..
 
that dp will over fuel aka fail its cat test for sure in the 01-03 cars.


looks like a dhp timing file. its one higher then stock wot.
 
That BIN started life as a "stock" 12226105 Regal file from the dropbox. I compared it to an 01 GTP file and the tables look the same. Is there a table you're looking at that I'm not?
 
you need to copy every folder over, not just this or that one, they all have changes.

the only things i dont swap over if theres a year change is the diagnostic folders, where you delete codes, cause they are not the same, and your maf hertz part of the maf file. what ever the top file is in the maf folder keep that one stock for your car. you can tune it later if you need to.

and make sure the injector file is stock too, unless your changing them. some of them tuned bins have injectors swaps in them, and then also double check the rpm and mph shifts in the tranny folder, cause those might be to high for you.
 


Ah yeah, the MAF table is different because I was experimenting with the MAF tuning from the Jerry guide. I'll set that back to stock too. The transmission stuff is pulled from my old "1.5" BIN which worked for me then, but I'll make it more conservative.
 
i gave up on the table modifier thing. i really dont think it makes a large enough swing at things, why it takes 5 to 10 scans and blah blah blah. waste of gas.

if you got your old trany file and it had stock ish shift points, use it. dont think id shift it at 5800 on stock valve springs, cause 5800 ends up really being 6000 or 6100.
 
Yeah, I'm starting to see that.. I put the stock MAF table back in, reduced some of the shift points, and moved the timing above 4000 RPM (where I was seeing 99% of the KR) down 3% in the Good Fuel Spark table. That's the best place to change the timing, right? I'm a little fuzzy on what Mean Best Torque Spark does exactly.
 
Badass. Thanks, man! There's still salt on the road from last night, so no test drive's today, but I'll let you know how it is next time I get it out.
 


Dropped the WOT GFS down to 10.04 (decreased it by 3% a couple of times until I got something the car liked) from 11.00 for the 4000-5200 RPM range.

Seems to have liked that, only little blips of KR now to figure out. Thanks for getting me on the right track!
 
And it's back to basically how it was. ~1.5-2.5 degrees of KR, not every single run, but sometimes. Guess it just really liked the super cold weather yesterday.

Is it normal to have to back timing off this much?
 
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