KR elimination

[BillBoost37]

I had done something like 5+ before I noticed improvement. Some will say do an hour or two scan to get the averages closer before pasting half and others will tell you 20-30 minute runs will work. There's a pile of ways to accomplish the same thing, in the end it seems like it takes a good amount of time no matter how you go about it.

[99ssei]

My commute to work is one hour with mostly city and very little highway (20 miles each way). Just bought a power inverter on my lunch break so that I can log scans every day to and from work. For some strange reason, I have this little voice in my head repeatedly saying in a deep, husky Mr. T voice, "I'm gonna get you sucka!"

[Allmachtige]

Wow that hotwire kit is nice. Would it be beneficial on a 2000+?

Also for reference... Last night I did some WOT tests coming home from work and hit 5.5KR with 10.9 LTFT. Seems you had similar fuel trims.

[superchargedSSEi]

It's not how long you drive but how you drive while scanning (same with relearning fuel trims). This is some good scanning advice (applicable to almost any tune) taken from JerryH's tuning notebook:

In 3rd gear, performance mode (if available) is activated and if idle and cruise LTFTs are our goal for this scan I scan using the following parameters as a minimum: gear, IAT, IPW, KR, LTFT, STFT, MAF Hz, Map kPa, MPH, O2, RPM, Spark, Current Gear, Fuel Cell and TP%.

Here is the secret to getting a good scan... you need a VERY slow progression from low Map kPa values up to 110 Map kPa or so. This is done by very slowly rolling into the throttle. Remember we are still in 3rd gear because it gives you a much better resolution than 4th. The slower and more gradual climb in Map kPa, the better. The reason you want to go a LITTLE into boost is that you see what the LTFTs and STFTs are locking in at once you are in boost.




I like to have at least 20 data points for each cell in whatever table I'm tweaking, and hundreds of data points for the cells that fall around the 100kPa/ 0psi area since that's mostly what determines your WOT LTFT. I also pick out any data that was collected during TC lockup, throttle blips, sitting at a light, or while decelerating to get rid of any garbage numbers. You can even go the extra step and tune each table in sections (ie. cruise, light, half, and wide open throttle) instead of tweaking the whole thing at once.

[99ssei]

Ok, so I couldn't wait for Saturday to come.
Here's my first 50 mile scan.
NOTE: These are the actual numbers - Not averaged
EDIT: PE mode disabled (set to 100%), MAF disabled

[DaBlackPearl]

Cool graphs but what is your KR at now?

[99ssei]

Cool graphs but what is your KR at now?

This was the first scan to see where things are at (VE Tuning). No changes have been made yet. This part of the tune requires PE and MAF to be disabled and not to go WOT. KR during the scan remained at 0.0.

I noticed all the LTFT's are at 0. According to Gary's Guide, I should be between +/-5. Looks like no changes were needed. Can I move onto calibrating the MAF?

[Allmachtige]

Were your LTFT's always 0.0? I thought you had a lean condition even without going WOT.

[Dirthead Racing]

Am I seeing all of your STFT's at 16+ but your LTFT's at 0?????something isn't right there at all. Did you reset your fuel trims when you flashed your latest bin file? Sorry but even the best tuners out there won't get all of thier LTFT's to read at zero across the board. Something isn't right.

[Allmachtige]

Am I seeing all of your STFT's at 16+ but your LTFT's at 0?????something isn't right there at all. Did you reset your fuel trims when you flashed your latest bin file? Sorry but even the best tuners out there won't get all of thier LTFT's to read at zero across the board. Something isn't right.

Ok I'm not the only one thinking something is off then. Even when cruising my LTFT's bounce between 6.6 and 10.9 on average.

[99ssei]

Am I seeing all of your STFT's at 16+ but your LTFT's at 0?????something isn't right there at all. Did you reset your fuel trims when you flashed your latest bin file? Sorry but even the best tuners out there won't get all of thier LTFT's to read at zero across the board. Something isn't right.

Yeah, I'm concerned about that too. Something doesn't look right. I reset the fuel trim at the beginning of the test through the HP Scanner.

[superchargedSSEi]

Drive around for a couple of days without resetting the fuel trims, then rescan. The large STFT values are one clue that the fuel trims weren't relearned yet. You'll also probably never see your LTFTs go to 0 during a VE tune...another red flag. Speed density is just too sensitive to weather changes to get it that accurate which is why LTFTs within +/-5 are acceptable and +/- 3 are excellent. Don't move on to the MAF tune until you get your LTFT into that range, preferably on the rich side of it. That aside, looking at the tables your first scan was pretty successful as far as scan technique goes...only a few cells are missing data. Nice job.

[BillBoost37]

One of the nice things about HPT is you can watch that histogram for LT's while driving to see how much you are hitting the various cells. They even turn a different color and you can only take averages on the cells over X number of hits.

[99ssei]

Drive around for a couple of days without resetting the fuel trims, then rescan. The large STFT values are one clue that the fuel trims weren't relearned yet. You'll also probably never see your LTFTs go to 0 during a VE tune...another red flag. Speed density is just too sensitive to weather changes to get it that accurate which is why LTFTs within +/-5 are acceptable and +/- 3 are excellent. Don't move on to the MAF tune until you get your LTFT into that range, preferably on the rich side of it. That aside, looking at the tables your first scan was pretty successful as far as scan technique goes...only a few cells are missing data. Nice job.

Thanks! After gathering the data, I reset the fuel trim through the scangauge (instead of through the HP Scanner), enabled PE mode (48 constant) & MAF, then wrote file to PCM. I drove about 6-7 miles after that last night. I car pooled today, but plan on driving 20 miles tonight (going to visit my newly born niece at the hospital!). I'll hook the laptop up and scan for LTFT again. If I see them moving, then I'll do another 50 mile scan.

[Dirthead Racing]

One of the nice things about HPT is you can watch that histogram for LT's while driving to see how much you are hitting the various cells. They even turn a different color and you can only take averages on the cells over X number of hits.

That is nice, I don't have that option :sad5:

[99ssei]

Since my first 50 miler didn't log the LTFT. I did another 50 miles last night. As expected, majorly lean all over the graph. I saved the scanner config, but didn't save the data, so I don't have graphs to show. I did save it to an excel spreadsheet and worked off of that. Here are the LTFTs from the 2nd 50 mile run.

EDIT: Crap, site doesn't like copy / paste. I'll re-do here. FIXED


I'm on my second adjustment and heading out the door to do my third.

EDIT2:
Here are the winning lottery numbers......
Re-write # 2


Re-write # 3


Re-write #4


Now I'm onto the MAF calibration.

I'm a little stuck here....Gary's write up uses the MAF in hz. the VCM Scanner captures MAF in lb/min. Any suggestions how to translate to hz? or help figuring out how to calibrate the MAF. I have the data (after MAF/PE enabled re-write #4) stored in a .csv file.

[superchargedSSEi]

I prefer to have all of the LTFTs on the rich side before going on to the MAF tune but all the numbers are close enough (other than where you're pulling vacuum at high rpm) that everything should come together after tweaking the MAF table a few times.

Check to see if there's an option for another way to capture the MAF data. The MAF output is in Hz and corresponds to the airflow in g/sec so I don't get why the scanner is reading everything in lb/min.

[99ssei]

HPT said I can log using Hz instead of lb/min. Just got to find the setting in the program.

With MAF/PE enabled, my first scan


10 revisions later, my latest scan


still working out the kinks....

[Allmachtige]

So is most of your KR gone now after the adjustments?

[99ssei]

Not quite. I'll post the latest numbers when I get home tonight, but my LTFTs are all +/- 2 except for the idle / lower cruise numbers. Those are a little lean (4-5 range) which is fine with me because I can save a little on gas while at cruising speed and still have power when I need it. I have noticed very substantial power gains using my trusty ol' meter! Now that my MAF calibration is where I want it, I'm moving onto the 02s. Gary's write up says to get the WOT #'s between 930-940. After that, I start notching out the KR. Today at lunch, I seen 0 KR until I get WOT at or above 4K rpms. Then it hit 5 & 6, BUT it was also 95 degrees outside. Last night, when it was 74 degrees, it only hit 2. Needless to say, I'm chipping away at it ever slowly.

I've driven about 200 miles for the PE tables, 100 miles for the MAF calibration, probably another 100 for the O2's, and another 100 for the KR. This is no easy process, but I'm definitely seeing the power gains from doing it!