osuhog

iTrader: (16)

After paying a lot of money for a terrible dyno tune from a local shop, I had a very gracious forum member here get me fixed up with a great tune by email for no charge. That said, I bought my own HPT Pro & an AEM wideband & have been trying to learn a little more about tuning myself so I can make my own changes for any future mods.

So, I have started with attempting to get my VE tables dialed in perfectly & I’m at a bit of a loss already. I’ve read a bunch & feel like I have a pretty good understanding of what to do, but I must be missing something.

I set up a VE/AFR error histogram, made the appropriate changes to my tune (disabled/unplugged MAF, etc) & did a bunch of driving & logging. I then corrected my main VE table by copying the #’s from the error histogram with 50+ hits & using “paste special multiply by percentage” in the VE table. I then copied over the even columns to the secondary table & repeated this procedure several times until I got everything pretty much spot on under 3200 RPM’s. All the cells in my error histogram are reading 0-2 now & my afr & desired afr matches right up no matter where I’m at on the throttle.

My car runs really good with these changes, but I have a slight problem. I changed everything back on my tune so the VE tables are the only differences between this & my starting point email tune. When I start the car, cold or even partially warmed up (when it’s still in open loop I suppose), I have to wait a minute or so before putting the car in gear. If I put it in gear a little bit after I start it, it just dies. Again, no other changes from the email tune (which doesn't have this problem at all).

My VE tables are anywhere from a few points lower per cell all the way to 12-15 points lower in the cells around idle, fyi.

Any ideas on what I’m missing? At this point, I’ve just gone back to the VE table from the email tune & got & am very happy with it. I’m just trying to get this figured out for my own piece of mind & as part of the learning process of tuning.

Thanks in advance!

CLRD4TO

iTrader: (4)

Sounds like you're on the right track for your VE, but now you have to play with idle tuning. It sucks. Your 1200 columns and lower rpm shouldnt have any more % change than the rest of your VE changes. If its more, youre fighting idle tables with the VE.

First is to narrow down the Idle Airflow Table. Set up a histo with that table (vs afr error)and force OL. Log from cold start to warm up idling only. Tune the idle airflow just like you have with your ve. Takes a long time since you want it cold again to adjust more that just one cell.

I had a hell of a problem with it bucking in lower gears at idle cruise. Also had I high hanging idle until the car would come to a stop. Found my idle spark table did not match the idle area of the main spark. Just a tip there. You should also have your over/under speed tables increased if youre also having trouble with idle speed. Keep in mind, the ls1 like mid/upper 20's of idle timing. Set your idle spark to 20 or lower and adjust underspeed as needed to reach mid 20's. Another tip!

Have fun!

C5kid

iTrader: (12)

are you plugging your MAF back in? Because that will have to also be adjusted. There is a config file on HPTunersforum that takes your MAF and A/F % error and lets you quickly copy and paste the #'s into the MAF table.

osuhog

iTrader: (16)

Excellent, thanks for the info guys. Yes, I did plug the MAF back in & I tuned it for AFR error also. I will try the idle airflow table next as mentioned above & keep this thread posted in the next few days. Thanks again for the help!

osuhog

iTrader: (16)

Okay, here was my first run with the idle airflow error histogram (running pretty lean at low temps obviously). Just made the changes to the tune, got it uploaded, & waiting for the car to cool back down now. I'll try to log some more later tonight & see how much closer it is. Hopefully this will solve my problem. Thanks again for the help!