MAF-STFT tuning.... 15% error with just a VCM OTR installed?

[GMpowered1]

I'm trying to determine if the information I got from my log today is good or if I have an issue.
I have a g8gt with a VCM OTR intake installed. The intake was installed before I owned HPtuners so I have no idea what the MAF in stock form looked like.
I checked for an intake and exhaust leak.

I started logging MAF(HZ)-STFT and got the following:

http://s1343.photobucket.com/user/jv...tml?sort=3&o=0
Note: I drove the car around awhile until the iat's dropped below 80 degrees.

I was expecting these numbers to be about half of what I logged. Is it normal for a CAI to cause 15% STFT error?

If this data is good I'll start dialing this thing in but I just not sure right now.

[BigDaddyCool]

Post Scan/Tune...... Best bet here so we know what your looking at.

Was the VCM OTR installed by someone else or yourself? Was there a maf tune or any tuning done for it?......

OTR's generally have quite a swing off throttle rolling in gear mostly....... but to give you an idea, I have a VE SS, virtually the same as a G8 GT with a Ramjet OTR, mine are at absolute worest at +9 in those minor spots at present.

Mine were upto +30 sometimes before I started fixing all that to give you can idea = very bad, 15%.... as long as LTFT's are enabled, the car can atleast compensate for that .... worest case scenario

Post tune/scan.

[GMpowered1]

I would post my tune/scan but I'm not sure how. I only know how to post an image using the "insert link". I don't see an attach file button.

I installed the VCM about a month ago. No tuning done. I'm trying to do it now.

[ttz06vette]

I would post my tune/scan but I'm not sure how. I only know how to post an image using the "insert link". I don't see an attach file button.

I installed the VCM about a month ago. No tuning done. I'm trying to do it now.

It's the little paper clip icon on the top menu bar like with MS office products.

[GMpowered1]

wow, I just realized that you have to click "Post reply" not "quick reply" in order to attach stuff.

Well my new prob today is that I can't open the log I did yesterday. When I ope the "saved" file...everything is blank. PIA.

Ill run another log an try to post it.

[GMpowered1]

Here is the log I took today. The tune hasn't been touched yet other than the tweaks required to log the data. I attached the tune too for haha's.

Let me know if you think the values are abnormally high.

I'm starting to think the values are right..but it's just off that everything is positive. NO negative STFT values.

[BigDaddyCool]

Needs to be maf tuned it's lean.

1. Re-Enable Dynamic Airflow. Disable 4000rpm, Re-Enable 3900.
2. Multiply the MAF table by 1.02 to add 2% more fuel over the whole table... for a starting point looking at that.
3. Read up on maf tuning.... wideband and narrowband.

Look at my log to give you an idea, there's alot of things that need to be changed when you put in a OTR intake..... because you move the maf sensor so air temp calibrations change and so on.....

Ignore my LTFT's and knocking at launch stuff.....

[flame]

Make sure you clean the maf before you start tuning

[GMpowered1]

1. Re-Enable Dynamic Airflow. Disable 4000rpm, Re-Enable 3900.

This would RE-Enable VE. I thought MAF tuning was done with VE off. There really isn't any reason to have VE on right? The car will tune and run fine with VE off right?

there's alot of things that need to be changed when you put in a OTR intake...

What are the changes your talking about? I looked at your log and can tell your fuel is dialed in much better but what changed did you make other than adding fuel to the MAF table? I thought this was all that was required to get the OTR in check?

I will clean my MAF. Hasn't been done in at least 30K

[GMpowered1]

Also, My car seems to idle around 2550 and 2700 Hz. Will adding fuel to the 2550, 2700 Hz cell help wit the rough idle I have. This car has always had a bit of a rough idle but ever since I put the CAI it got worse.

Also when I flash the car with the Pre-log tune which disables VE, DOD, decel etc. the car seems to idle a bit worse... I hate the idle on this car. fells like its misfiring sometimes...even though I know its not.

[GMpowered1]

Hey guys I noticed that my car idles at 2550Hz and after a few MAF logs/adjustments things are getting much better BUt now my car idles at 2400HZ. And the reading at 2400 and 2550 is really lean.. 19% at 2400HZ and 12 at 2550 Hz everything else is between 2 and -2 now.

Should I be messing with Hz that low? Should I raise my idle? where is that located in HP?

[GMpowered1]

So, I spent a bunch of time looking over my car for air leaks. I ran a new PCV hose to my VCM OTR because the stock one doesn't work that great. Carefully sprayed carb cleaner around TB and other vacuum lines and did not get the idle the change.

I read over my original log and realized I didn't let the car get to operating temp before logging. I also noticed that once my car is at op temp, my iat can become heat soaked rather easily. I think the heat-soaked iat and/or logging before the car is in closed loop contributed to the logs that I thought were abnormal (leanish in spots).

Anyway I went through and tuned the MAF table via 5 or so iterations of multiplying half % to all cell up to 7000ish Hz. Tried to only modify cells that recorded a cell count of at least 200 hits.

I've attached the log and the tune. Please read over the log and tell me if anything points to an air leak of any kind.

Any help or pointer would be great. I know I need to continue to clean up the tune but I just want to see if anyone thinks I have a mechanical issue before continuing. I don't want to be tuning around an intake leak of some kind.

[GMpowered1]

crickets huh? That's unfortunate.

[Cal]

If it is only the idle fuel trims that are a problem, it is possible the MAF is in turbulent airflow at idle. Look at the MAF output to verify it has a steady output. If it moves around more than 1 gram per second at idle, this could be your problem. The fix is to rotate the air filter 90 degrees, if possible, or add an airflow straightener.

HTH,
Cal

[BigDaddyCool]

If it is only the idle fuel trims that are a problem, it is possible the MAF is in turbulent airflow at idle. Look at the MAF output to verify it has a steady output. If it moves around more than 1 gram per second at idle, this could be your problem. The fix is to rotate the air filter 90 degrees, if possible, or add an airflow straightener.

HTH,
Cal

The best way is to compensate for the low idle maf regions where you can. Eg. Maf, air charge temps and ve. It'll never be perfect but you can get it close. Raising the idle eg. 550 to 600 keeps the maf from hitting the trouble spots so much as well.....

[G8V8]

Something to think about is that the VCM draws air for the PCV system from the VCM housing which is upstreem of the MAF. This air eventually get drawn into the intake manifold. This means that the air is unmetered by the MAF so no corresponding fuel is provided for the PVC air. systems like roto-Fab and Vararam draw PVC air from between the MAF and throttle body.

[GMpowered1]

I seemed to have gotten the part throttle tune decent and I raised the idle 25 rpm. Sightly raised rpm is better. I always thought the idle was a tad low anyway.

Now my big issue is trying to set up a histo for WOT tuning...
I have a WB installed and reading the correct 1.0 lambda in HPtuners down in the EIO input section. small section at the bottom of the table. But I can not seem to get the histo 11 (i find so often on threads) to work.

I was playing around in the hist config and realized that a pid for %error lambda does not exist. Do I have to make one?

[GMpowered1]

I figured it out.

[BigDaddyCool]

Are you tuning this in closed loop with the wideband? Do you have the wideband up front or after your catalyst converter? - from the looks of the log,

I find most tuners raise the idle alot with OTR's, I went from 550rpm to 600rpm

[GMpowered1]

The WB is installed in my LT so its precat. But I'm not running cats. Also its at WOT so that would be closed loop/PE.