maf calibration questions

[LETZRIDE]

I have been attempting to dial in my maf tables using Russ Kemps guide on the Hp tuners website...I put the VE tables back to stock...zeroed out the PE tables, etc, etc

I turned closed loop off...my command afr was staying perfect at 14.7...

This is the guide... http://www.hptuners.com/forum/showth...oop+maf+tuning


anyways...I logged my numbers for part throttle...I got inbetween 2500hz and 7500hz of data... I copied the info and pasted using "special multiply by %" function...I then took my lowest number (2500hz portion of the table) and put that number into the rest of the low end table I couldnt hit...

The numbers were whack on the maf table...I had some numbers that were reading at 511 g/sec...it seemed off to me, since the original numbers were wayyyyy different...

anyways I flashed it in and the car wouldnt start....so needless to say, I have reverted back to square 1 and flashed the working tune back in...anyone know what might be going on...

I'll attach my maf table...

mafissue.txt

[bigbrian442]

Re: maf calibration questions

Send me the scan and your tune and I'll take a look. Do you still have my email?

[LETZRIDE]

Re: maf calibration questions

I'll send you the tune now, and I'll have to re-scan tommorrow...for some reason my scan corrupted... I am sure I have simply just made an error somewhere...but I went over it three times...from what I understand, I use paste special %, then after I use that and fine tune my afr (not sure how I go about doing that yet, since all the tables are set at 14.7, and the PE tables have been all zeroed out...Im assuming I go back to those tables and make fine adjustments) then I go back and copy whats already on the table and hit past special %-half....I think?

[bigbrian442]

Re: maf calibration questions

Did you reset the fuel trims and make sure your have both the scanner and editor set to read in the same units, imperial or metric?

[LETZRIDE]

Re: maf calibration questions

Did you reset the fuel trims and make sure your have both the scanner and editor set to read in the same units, imperial or metric?

I think that was my problem...I sent you another email...I lost my flippin scans again though...laptop died as I was clicking the save button, I love it...

fuel trims were reset...the car always acts weird when I reset the fuel trims and put it in open loop...acts like there is a vaccum leak almost...revs from 500-1500 rpm constantly when in park...in drive it is ok, but if you pop it back into neutral it begins going up and down again...

also, I noticed in preforming this procedure for tunning for part throttle, the car runs stupidly rich....Command AFR is 14.7...but it idles at 13.5ish...drives at anywhere from 12-13ish...numbers were as low as in the 11's that I saw... is it supposed to be this low when you do this?

[bigbrian442]

Re: maf calibration questions

That's normal. As you get the MAF table closer, it will act better. You will see a good change in the AFR error just from the first adjustment.

[flamingchicken]

Re: maf calibration questions

ok, so i wont be buying hp tuners anytime soon! good luck LETZRIDE.

[bigbrian442]

Re: maf calibration questions

ok, so i wont be buying hp tuners anytime soon! good luck LETZRIDE.

He's got it now. Was just a small oversight.

[LETZRIDE]

Re: maf calibration questions

sweet...so, you said I need to do this a few times...how do you know when you have done it enough to multiply by %1/2?

[bigbrian442]

Re: maf calibration questions

When the error % starts getting worse then the previous scan. Two or three times usually then you need to go to X % 1/2.

[LETZRIDE]

Re: maf calibration questions

sweet...what exactly does the x % 1/2 do to that table?...like what would be the difference if you were to leave the table numbers as is for say your third scan, rather then multiply it by % 1/2

I look at some of these tunning guides and read through them...and I understand why you would do 3/4 of the stuff...but some of it I dont quite understand what it means or why you would need to do certain steps...

[bigbrian442]

Re: maf calibration questions

sweet...what exactly does the x % 1/2 do to that table?...like what would be the difference if you were to leave the table numbers as is for say your third scan, rather then multiply it by % 1/2

I look at some of these tunning guides and read through them...and I understand why you would do 3/4 of the stuff...but some of it I dont quite understand what it means or why you would need to do certain steps...

I believe it adds half the percentage that shows in the error histogram to that block where the other adds the percentage.

[LETZRIDE]

Re: maf calibration questions

Ok so Im back to tuning...and I'm making some good progress...The new wb sensor says I dont really fall below 11.8...and Im not going lean up top like I thought I was.

So my table is coming along, my graph still looks a little wacky, but its smoothing out slowly.

My command afrs seem to still want to go all the way down to 12 at some points, and I am wondering something. Does the PE table for add vs RPM calculate based off of the Base AFR vs ECT table?

I set my richest cells to -1.000...and since my base table is 13.00 across the board...it leads me to believe that the add vs. rpm table calculates from this.

So my next question if I am correct in assuming this is if I knock the base table to 13.5 across the board...will this have a negative effect on my part throttle tuning? My part throttles are pretty bang on...

[bigbrian442]

Re: maf calibration questions

Part throttle is not effected unless your in PE mode.

[LETZRIDE]

Re: maf calibration questions

ok perfect...I ran out of battery before I could change the base table to 13.5 across the board....and the car goes in the shop 8am tommorrow so I can't try anything again until probably thursday... Am I correct in assuming the computer calculates commanded afr based off off that base table, and then adding/subtracting the PE tables from that?