MAF tuning
 

is there a how to on this anywhere on here, i didnt see it up in the stickys

from what ive saw you have to disable the MAF then tune VE, once thats good how do you know what numbers to enter in for the MAF?

once you've finished tuning your VE you would then reenable the maf & tune that, there are no set numbers.

Many parts of this how to will transfer over to the p12 pcm http://www.thetuningdoctor.com/HPTun...uningGuide.doc so would be a very good starting point.

All you really need to do when you get to that stage is record histograms and then rewrite the tables by hand using your experience. You CAN copy them, but it's better to understand what you are looking at so you don't copy over any rogue data. Do it multiple times until you get it closer and closer each time.

yea i have VE tuning experience from years with my eco cav, that concept I understand totally its the MAF stuff I dont

so you just do the AFR error vs maf thing and slightly add or decrease the maf number at that frequency?

i have that ls1 tuning document and from what it says there you base the whole thing around the VE numbers

MAF has jack shit to do with VE in our cars. they will only use the VE numbers if the MAF is failed or is reading incorrectly.
set up a histogram to log your wideband data vs your maf sensor frequency. you should have a single row of cells which record an average percentage of maf sensor error. copy these percentages and paste special (multiply by percent minus half) into your MAF table of your editor.

THANK YOU! I am glad others agree. If you don't tune the MAF you don't run right. I don't even touch VE in our cars for most cases. I've tried.....it doesn't make teh engine act any differently because the tables are useless.

That would explain it since teh 2.2L cavies had no MAFs

That document was originally intended for E40 LS2's but most of it is applicable to the P12 as well.

I see some good stuff in there

for some reason just having one row of data seems too easy :) so i guess thats where my worries were

One thing that I am going to add to this discussion is the following:

You are running 60s, right? Stay away from VE tuning at first. Start by tuning MAF from 1.2ms on up untill it is dialed (using a plot filter). Then change your plot filter to 1ms and above and see how it goes. Then remove your filter entirely and see how it compairs. The reason for this is because it will give you a chance to distinguish MAF errors from low PW fueling errors so that you can properly get your adders dialed in. The process is much easier to do in MAF, especially since there are some cells that deliver PWs above 1ms and below 1ms depending upon whether you are accelerating or in decel.

When you're done getting your adders dialed, go ahead and tune the VE to your heart's content. VE does play a part in our cars during transitional throttle situations and stuff. Not so much that it has to be dead nuts, but if it close and smooth, you should notice a difference.

What is a plot filter?

Open the histogram settings for your MAF histo (or any one for that matter) and you will see the option of using a plot filter. hit the "?" and you will see the different sensors and PIDs that you can use to apply filters. you put in the sensor name and the condition. Say for instance you want to filter out the lean spikes or DFCO, you would enter [sens.120] < 17 (iirc). That is telling the histo to only record info where the AFR is less than 17.00. I do not remember the pid for injector PW average bank 1, but it is in there somewhere...

ve plays a role in cruise control. it means dick in 07's. you can make it look like a pair of tits and the car will run the same.

Depends on your definition of "runs the same". I can tell a difference, but perhaps I am even more anal retentive than you are Bryan. :) Mostly the difference is in tip in, on/off throttle, etc... I have also noticed a slight difference on the swing of the trims at times during idle and just off idle, but that could have been my imagination.

not running 60s yet but thats the eventual destination, hmm a VE that looks like boobies! that would be cool

im totally confused here - Start by tuning MAF from 1.2ms on up untill it is dialed (using a plot filter).

No idea what that means, whats pulsewith anywhere in the maf table?

It made no difference in my 06 either

In my 05 I found that doing the VE made is quite a bit smother. This was with 42s and 60s on a 2.8" and 2.6". I didn't get tip-in knock as much after I did VE either.

^bingo

don't stab the gas = no tip in knock.

:)

steve. it's your imagination.

im actually going to make a ve map look like a pair of tits and start sending it to people


i has jokes

Set up a MAF histogram that shows your plot as the MAF hz and your data as ARF error. Then go to plot filtering in your histogram and set the filter to only allow the data that is above 1.2ms. That way you can tune most of your MAF without worrying about low PW errors giving you bad data. Once you have the MAF dialed that way set up 2 VE table histos, one reading AFR error and one injector PWs. By looking at the VE AFR error histo, you can see where your rich/lean errors are and by looking at the corrisponding cells in your VE injector PW histo, you can see what PWs are being commanded during those errors. That lets you know where to tweek the adder table to eliminate your low PW errors.

:(...

hehehehe. im always good for some sort of screwed up joke somewhere.

Jokes. He has them...

Yea, now only if you can figure out why I am commanding 18* of timing and only logging 12.5*...

uhhhhhhh dunno.

sooo anyone feel like playing with my tune, my shit is off, an I don't have any damn time anymore to work on the car.... just upper RPM's are screwy. any free time I've had I'm working on other's cars.... my poor car needs some lovin too lol

Yea, I can take a look at it if you want and maybe point you in a direction. I am finding out though that a lot of injector settings change quite a bit from injector to injector. I could get you to a place to start and let you know where to go from there, but it would still require some work on your part to dial them in. Let me know.

that' no problem, I just don't have the time to sit and datalog anymore.... 14 hr work days suck... plus I need to get my truck together asap so I can take the cobalt apart again